New Example - Calendar (#91)

flutter_date_pickers-master/lib/flutter_date_pickers.dart

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+export 'package:flutter_date_pickers/src/date_period.dart';
+export 'package:flutter_date_pickers/src/date_picker_keys.dart';
+export 'package:flutter_date_pickers/src/layout_settings.dart';
+export 'package:flutter_date_pickers/src/date_picker_styles.dart';
+export 'package:flutter_date_pickers/src/event_decoration.dart';
+
+export 'package:flutter_date_pickers/src/day_picker.dart';
+export 'package:flutter_date_pickers/src/week_picker.dart';
+export 'package:flutter_date_pickers/src/month_picker.dart';
+export 'package:flutter_date_pickers/src/range_picker.dart';
+
+export 'package:flutter_date_pickers/src/unselectable_period_error.dart';

flutter_date_pickers-master/lib/src/basic_day_based_widget.dart

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+import 'package:flutter/material.dart';
+
+import 'date_picker_mixin.dart';
+import 'date_picker_styles.dart';
+import 'day_type.dart';
+import 'event_decoration.dart';
+import 'i_selectable_picker.dart';
+import 'layout_settings.dart';
+import 'utils.dart';
+
+/// Widget for date pickers based on days and cover entire month.
+/// Each cell of this picker is day.
+class DayBasedPicker<T> extends StatelessWidget with CommonDatePickerFunctions {
+  /// Selection logic.
+  final ISelectablePicker selectablePicker;
+
+  /// The current date at the time the picker is displayed.
+  final DateTime currentDate;
+
+  /// The earliest date the user is permitted to pick.
+  /// (only year, month and day matter, time doesn't matter)
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  /// (only year, month and day matter, time doesn't matter)
+  final DateTime lastDate;
+
+  /// The month whose days are displayed by this picker.
+  final DateTime displayedMonth;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  ///  Key fo selected month (useful for integration tests)
+  final Key? selectedPeriodKey;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles datePickerStyles;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overridden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  /// Localizations used to get strings for prev/next button tooltips,
+  /// weekday headers and display values for days numbers.
+  final MaterialLocalizations localizations;
+
+  /// Creates main date picker view where every cell is day.
+  DayBasedPicker(
+      {Key? key,
+      required this.currentDate,
+      required this.firstDate,
+      required this.lastDate,
+      required this.displayedMonth,
+      required this.datePickerLayoutSettings,
+      required this.datePickerStyles,
+      required this.selectablePicker,
+      required this.localizations,
+      this.selectedPeriodKey,
+      this.eventDecorationBuilder})
+      : assert(!firstDate.isAfter(lastDate)),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    final List<Widget> labels = <Widget>[];
+
+    List<Widget> headers = _buildHeaders(localizations);
+    List<Widget> daysBeforeMonthStart = _buildCellsBeforeStart(localizations);
+    List<Widget> monthDays = _buildMonthCells(localizations);
+    List<Widget> daysAfterMonthEnd = _buildCellsAfterEnd(localizations);
+
+    labels.addAll(headers);
+    labels.addAll(daysBeforeMonthStart);
+    labels.addAll(monthDays);
+    labels.addAll(daysAfterMonthEnd);
+
+    return Padding(
+      padding: datePickerLayoutSettings.contentPadding,
+      child: Column(
+        children: <Widget>[
+          Flexible(
+            child: GridView.custom(
+              physics: datePickerLayoutSettings.scrollPhysics,
+              gridDelegate: datePickerLayoutSettings.dayPickerGridDelegate,
+              childrenDelegate:
+                  SliverChildListDelegate(labels, addRepaintBoundaries: false),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  List<Widget> _buildHeaders(MaterialLocalizations localizations) {
+    final int firstDayOfWeekIndex = datePickerStyles.firstDayOfeWeekIndex ??
+        localizations.firstDayOfWeekIndex;
+
+    DayHeaderStyleBuilder dayHeaderStyleBuilder =
+        datePickerStyles.dayHeaderStyleBuilder ??
+            // ignore: avoid_types_on_closure_parameters
+            (int i) => datePickerStyles.dayHeaderStyle;
+
+    List<Widget> headers = getDayHeaders(dayHeaderStyleBuilder,
+        localizations.narrowWeekdays, firstDayOfWeekIndex);
+
+    return headers;
+  }
+
+  List<Widget> _buildCellsBeforeStart(MaterialLocalizations localizations) {
+    List<Widget> result = [];
+
+    final int year = displayedMonth.year;
+    final int month = displayedMonth.month;
+    final int firstDayOfWeekIndex = datePickerStyles.firstDayOfeWeekIndex ??
+        localizations.firstDayOfWeekIndex;
+    final int firstDayOffset =
+        computeFirstDayOffset(year, month, firstDayOfWeekIndex);
+
+    final bool showDates = datePickerLayoutSettings.showPrevMonthEnd;
+    if (showDates) {
+      int prevMonth = month - 1;
+      if (prevMonth < 1) prevMonth = 12;
+      int prevYear = prevMonth == 12 ? year - 1 : year;
+
+      int daysInPrevMonth = DatePickerUtils.getDaysInMonth(prevYear, prevMonth);
+      List<Widget> days = List.generate(firstDayOffset, (index) => index)
+          .reversed
+          .map((i) => daysInPrevMonth - i)
+          .map((day) => _buildCell(prevYear, prevMonth, day))
+          .toList();
+
+      result = days;
+    } else {
+      result = List.generate(firstDayOffset, (_) => const SizedBox.shrink());
+    }
+
+    return result;
+  }
+
+  List<Widget> _buildMonthCells(MaterialLocalizations localizations) {
+    List<Widget> result = [];
+
+    final int year = displayedMonth.year;
+    final int month = displayedMonth.month;
+    final int daysInMonth = DatePickerUtils.getDaysInMonth(year, month);
+
+    for (int i = 1; i <= daysInMonth; i += 1) {
+      Widget dayWidget = _buildCell(year, month, i);
+      result.add(dayWidget);
+    }
+
+    return result;
+  }
+
+  List<Widget> _buildCellsAfterEnd(MaterialLocalizations localizations) {
+    List<Widget> result = [];
+    final bool showDates = datePickerLayoutSettings.showNextMonthStart;
+    if (!showDates) return result;
+
+    final int year = displayedMonth.year;
+    final int month = displayedMonth.month;
+    final int firstDayOfWeekIndex = datePickerStyles.firstDayOfeWeekIndex ??
+        localizations.firstDayOfWeekIndex;
+    final int firstDayOffset =
+        computeFirstDayOffset(year, month, firstDayOfWeekIndex);
+    final int daysInMonth = DatePickerUtils.getDaysInMonth(year, month);
+    final int totalFilledDays = firstDayOffset + daysInMonth;
+
+    int reminder = totalFilledDays % 7;
+    if (reminder == 0) return result;
+    final int emptyCellsNum = 7 - reminder;
+
+    int nextMonth = month + 1;
+    result = List.generate(emptyCellsNum, (i) => i + 1)
+        .map((day) => _buildCell(year, nextMonth, day))
+        .toList();
+
+    return result;
+  }
+
+  Widget _buildCell(int year, int month, int day) {
+    DateTime dayToBuild = DateTime(year, month, day);
+    dayToBuild = _checkDateTime(dayToBuild);
+
+    DayType dayType = selectablePicker.getDayType(dayToBuild);
+
+    Widget dayWidget = _DayCell(
+      day: dayToBuild,
+      currentDate: currentDate,
+      selectablePicker: selectablePicker,
+      datePickerStyles: datePickerStyles,
+      eventDecorationBuilder: eventDecorationBuilder,
+      localizations: localizations,
+    );
+
+    if (dayType != DayType.disabled) {
+      dayWidget = GestureDetector(
+        behavior: HitTestBehavior.opaque,
+        onTap: () => selectablePicker.onDayTapped(dayToBuild),
+        child: dayWidget,
+      );
+    }
+
+    return dayWidget;
+  }
+
+  /// Checks if [DateTime] is same day as [lastDate] or [firstDate]
+  /// and returns dt corrected (with time of [lastDate] or [firstDate]).
+  DateTime _checkDateTime(DateTime dt) {
+    DateTime result = dt;
+
+    // If dayToBuild is the first day we need to save original time for it.
+    if (DatePickerUtils.sameDate(dt, firstDate)) result = firstDate;
+
+    // If dayToBuild is the last day we need to save original time for it.
+    if (DatePickerUtils.sameDate(dt, lastDate)) result = lastDate;
+
+    return result;
+  }
+}
+
+class _DayCell extends StatelessWidget {
+  /// Day for this cell.
+  final DateTime day;
+
+  /// Selection logic.
+  final ISelectablePicker selectablePicker;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles datePickerStyles;
+
+  /// The current date at the time the picker is displayed.
+  final DateTime currentDate;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overridden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  final MaterialLocalizations localizations;
+
+  const _DayCell(
+      {Key? key,
+      required this.day,
+      required this.selectablePicker,
+      required this.datePickerStyles,
+      required this.currentDate,
+      required this.localizations,
+      this.eventDecorationBuilder})
+      : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    DayType dayType = selectablePicker.getDayType(day);
+
+    BoxDecoration? decoration;
+    TextStyle? itemStyle;
+
+    if (dayType != DayType.disabled && dayType != DayType.notSelected) {
+      itemStyle = _getSelectedTextStyle(dayType);
+      decoration = _getSelectedDecoration(dayType);
+    } else if (dayType == DayType.disabled) {
+      itemStyle = datePickerStyles.disabledDateStyle;
+    } else if (DatePickerUtils.sameDate(currentDate, day)) {
+      itemStyle = datePickerStyles.currentDateStyle;
+    } else {
+      itemStyle = datePickerStyles.defaultDateTextStyle;
+    }
+
+    // Merges decoration and textStyle with [EventDecoration].
+    //
+    // Merges only in cases if [dayType] is DayType.notSelected.
+    // If day is current day it is also gets event decoration
+    // instead of decoration for current date.
+    if (dayType == DayType.notSelected && eventDecorationBuilder != null) {
+      EventDecoration? eDecoration = eventDecorationBuilder != null
+          ? eventDecorationBuilder!.call(day)
+          : null;
+
+      decoration = eDecoration?.boxDecoration ?? decoration;
+      itemStyle = eDecoration?.textStyle ?? itemStyle;
+    }
+
+    String semanticLabel = '${localizations.formatDecimal(day.day)}, '
+        '${localizations.formatFullDate(day)}';
+
+    bool daySelected =
+        dayType != DayType.disabled && dayType != DayType.notSelected;
+
+    Widget dayWidget = Container(
+      decoration: decoration,
+      child: Center(
+        child: Semantics(
+          // We want the day of month to be spoken first irrespective of the
+          // locale-specific preferences or TextDirection. This is because
+          // an accessibility user is more likely to be interested in the
+          // day of month before the rest of the date, as they are looking
+          // for the day of month. To do that we prepend day of month to the
+          // formatted full date.
+          label: semanticLabel,
+          selected: daySelected,
+          child: ExcludeSemantics(
+            child: Text(localizations.formatDecimal(day.day), style: itemStyle),
+          ),
+        ),
+      ),
+    );
+
+    return dayWidget;
+  }
+
+  BoxDecoration? _getSelectedDecoration(DayType dayType) {
+    BoxDecoration? result;
+
+    if (dayType == DayType.single) {
+      result = datePickerStyles.selectedSingleDateDecoration;
+    } else if (dayType == DayType.start) {
+      result = datePickerStyles.selectedPeriodStartDecoration;
+    } else if (dayType == DayType.end) {
+      result = datePickerStyles.selectedPeriodLastDecoration;
+    } else {
+      result = datePickerStyles.selectedPeriodMiddleDecoration;
+    }
+
+    return result;
+  }
+
+  TextStyle? _getSelectedTextStyle(DayType dayType) {
+    TextStyle? result;
+
+    if (dayType == DayType.single) {
+      result = datePickerStyles.selectedDateStyle;
+    } else if (dayType == DayType.start) {
+      result = datePickerStyles.selectedPeriodStartTextStyle;
+    } else if (dayType == DayType.end) {
+      result = datePickerStyles.selectedPeriodEndTextStyle;
+    } else {
+      result = datePickerStyles.selectedPeriodMiddleTextStyle;
+    }
+
+    return result;
+  }
+}

flutter_date_pickers-master/lib/src/date_period.dart

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+/// Date period.
+class DatePeriod {
+  /// Start of this period.
+  final DateTime start;
+
+  /// End of this period.
+  final DateTime end;
+
+  ///
+  const DatePeriod(this.start, this.end)
+      : assert(start != null),
+        assert(end != null);
+}

flutter_date_pickers-master/lib/src/date_picker_keys.dart

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+import 'package:flutter/material.dart';
+
+/// Keys for some date picker's widgets.
+///
+/// Useful for integration tests to find widgets.
+class DatePickerKeys {
+  /// Key for the previous page icon widget.
+  final Key previousPageIconKey;
+
+  /// Key for the next page icon widget.
+  final Key nextPageIconKey;
+
+  /// Key for showing month.
+  final Key selectedPeriodKeys;
+
+  ///
+  DatePickerKeys(
+      this.previousPageIconKey, this.nextPageIconKey, this.selectedPeriodKeys);
+}

flutter_date_pickers-master/lib/src/date_picker_mixin.dart

@@ -0,0 +1,99 @@
+import 'package:flutter/material.dart';
+
+import 'date_picker_styles.dart';
+
+///
+mixin CommonDatePickerFunctions {
+
+  /// Builds widgets showing abbreviated days of week. The first widget in the
+  /// returned list corresponds to the first day of week for the current locale.
+  ///
+  /// Examples:
+  ///
+  /// ```
+  /// ┌ Sunday is the first day of week in the US (en_US)
+  /// |
+  /// S M T W T F S  <-- the returned list contains these widgets
+  /// _ _ _ _ _ 1 2
+  /// 3 4 5 6 7 8 9
+  ///
+  /// ┌ But it's Monday in the UK (en_GB)
+  /// |
+  /// M T W T F S S  <-- the returned list contains these widgets
+  /// _ _ _ _ 1 2 3
+  /// 4 5 6 7 8 9 10
+  /// ```
+  List<Widget> getDayHeaders(
+      DayHeaderStyleBuilder headerStyleBuilder,
+      List<String> narrowWeekdays,
+      int firstDayOfWeekIndex) {
+
+    final List<Widget> result = <Widget>[];
+
+    for (int i = firstDayOfWeekIndex; true; i = (i + 1) % 7) {
+      DayHeaderStyle? headerStyle = headerStyleBuilder(i);
+      final String weekday = narrowWeekdays[i];
+
+      Widget header = ExcludeSemantics(
+        child: Container(
+          decoration: headerStyle?.decoration,
+          child: Center(
+              child: Text(
+                  weekday,
+                  style: headerStyle?.textStyle
+              )
+          ),
+        ),
+      );
+
+      result.add(header);
+      if (i == (firstDayOfWeekIndex - 1) % 7) {
+        break;
+      }
+    }
+    return result;
+  }
+
+  /// Computes the offset from the first day of week that the first day of the
+  /// [month] falls on.
+  ///
+  /// For example, September 1, 2017 falls on a Friday, which in the calendar
+  /// localized for United States English appears as:
+  ///
+  /// ```
+  /// S M T W T F S
+  /// _ _ _ _ _ 1 2
+  /// ```
+  ///
+  /// The offset for the first day of the months is the number of leading blanks
+  /// in the calendar, i.e. 5.
+  ///
+  /// The same date localized for the Russian calendar has a different offset,
+  /// because the first day of week is Monday rather than Sunday:
+  ///
+  /// ```
+  /// M T W T F S S
+  /// _ _ _ _ 1 2 3
+  /// ```
+  ///
+  /// So the offset is 4, rather than 5.
+  ///
+  /// This code consolidates the following:
+  ///
+  /// - [DateTime.weekday] provides a 1-based index into days of week, with 1
+  ///   falling on Monday.
+  /// - [MaterialLocalizations.firstDayOfWeekIndex] provides a 0-based index
+  ///   into the [MaterialLocalizations.narrowWeekdays] list.
+  /// - [MaterialLocalizations.narrowWeekdays] list provides localized names of
+  ///   days of week, always starting with Sunday and ending with Saturday.
+  int computeFirstDayOffset(
+      int year, int month, int firstDayOfWeekFromSunday) {
+    // 0-based day of week, with 0 representing Monday.
+    final int weekdayFromMonday = DateTime(year, month).weekday - 1;
+    // firstDayOfWeekFromSunday recomputed to be Monday-based
+    final int firstDayOfWeekFromMonday = (firstDayOfWeekFromSunday - 1) % 7;
+    // Number of days between the first day of week appearing on the calendar,
+    // and the day corresponding to the 1-st of the month.
+    return (weekdayFromMonday - firstDayOfWeekFromMonday) % 7;
+  }
+}

flutter_date_pickers-master/lib/src/date_picker_styles.dart

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+import 'package:flutter/material.dart';
+import 'range_picker.dart';
+import 'week_picker.dart';
+
+/// 0 points to Sunday, and 6 points to Saturday.
+typedef DayHeaderStyleBuilder = DayHeaderStyle? Function(int dayOfTheWeek);
+
+/// Common styles for date pickers.
+///
+/// To define more styles for date pickers which allow select some range
+/// (e.g. [RangePicker], [WeekPicker]) use [DatePickerRangeStyles].
+@immutable
+class DatePickerStyles {
+  /// Styles for title of displayed period
+  /// (e.g. month for day picker and year for month picker).
+  final TextStyle? displayedPeriodTitle;
+
+  /// Style for the number of current date.
+  final TextStyle? currentDateStyle;
+
+  /// Style for the numbers of disabled dates.
+  final TextStyle? disabledDateStyle;
+
+  /// Style for the number of selected date.
+  final TextStyle? selectedDateStyle;
+
+  /// Used for date which is neither current nor disabled nor selected.
+  final TextStyle? defaultDateTextStyle;
+
+  /// Day cell decoration for selected date in case only one date is selected.
+  final BoxDecoration? selectedSingleDateDecoration;
+
+  /// Style for the day header.
+  ///
+  /// If you need to customize day header's style depends on day of the week
+  /// use [dayHeaderStyleBuilder] instead.
+  final DayHeaderStyle? dayHeaderStyle;
+
+  /// Builder to customize styles for day headers depends on day of the week.
+  /// Where 0 points to Sunday and 6 points to Saturday.
+  ///
+  /// Builder must return not null value for every weekday from 0 to 6.
+  ///
+  /// If styles should be the same for any day of the week
+  /// use [dayHeaderStyle] instead.
+  final DayHeaderStyleBuilder? dayHeaderStyleBuilder;
+
+  /// Widget which will be shown left side of the shown page title.
+  /// User goes to previous data period by click on it.
+  final Widget prevIcon;
+
+  /// Widget which will be shown right side of the shown page title.
+  /// User goes to next data period by click on it.
+  final Widget nextIcon;
+
+  /// Index of the first day of week, where 0 points to Sunday, and 6 points to
+  /// Saturday. Must not be less 0 or more then 6.
+  ///
+  /// Can be null. In this case value from current locale will be used.
+  final int? firstDayOfeWeekIndex;
+
+  /// Styles for date picker.
+  DatePickerStyles({
+    this.displayedPeriodTitle,
+    this.currentDateStyle,
+    this.disabledDateStyle,
+    this.selectedDateStyle,
+    this.selectedSingleDateDecoration,
+    this.defaultDateTextStyle,
+    this.dayHeaderStyleBuilder,
+    this.dayHeaderStyle,
+    this.firstDayOfeWeekIndex,
+    this.prevIcon = const Icon(Icons.chevron_left),
+    this.nextIcon = const Icon(Icons.chevron_right)
+  }) : assert(!(dayHeaderStyle != null && dayHeaderStyleBuilder != null),
+        "Should be only one from: dayHeaderStyleBuilder, dayHeaderStyle."),
+       assert(dayHeaderStyleBuilder == null
+           || _validateDayHeaderStyleBuilder(dayHeaderStyleBuilder),
+        "dayHeaderStyleBuilder must return not null value from every weekday "
+            "(from 0 to 6)."),
+       assert(_validateFirstDayOfWeek(firstDayOfeWeekIndex),
+        "firstDayOfeWeekIndex must be null or in correct range (from 0 to 6).");
+
+  /// Return new [DatePickerStyles] object where fields
+  /// with null values set with defaults from theme.
+  DatePickerStyles fulfillWithTheme(ThemeData theme) {
+    Color accentColor = theme.accentColor;
+
+    TextStyle? _displayedPeriodTitle =
+        displayedPeriodTitle ?? theme.textTheme.subtitle1;
+    TextStyle? _currentDateStyle = currentDateStyle ??
+        theme.textTheme.bodyText1?.copyWith(color: theme.accentColor);
+    TextStyle? _disabledDateStyle = disabledDateStyle ??
+        theme.textTheme.bodyText2?.copyWith(color: theme.disabledColor);
+    TextStyle? _selectedDateStyle =
+        selectedDateStyle ?? theme.accentTextTheme.bodyText1;
+    TextStyle? _defaultDateTextStyle =
+        defaultDateTextStyle ?? theme.textTheme.bodyText2;
+    BoxDecoration _selectedSingleDateDecoration =
+        selectedSingleDateDecoration ??
+            BoxDecoration(
+                color: accentColor,
+                borderRadius: const BorderRadius.all(Radius.circular(10.0)));
+
+    DayHeaderStyle? _dayHeaderStyle = dayHeaderStyle;
+    if (dayHeaderStyleBuilder == null && _dayHeaderStyle == null) {
+      _dayHeaderStyle = DayHeaderStyle(textStyle: theme.textTheme.caption);
+    }
+
+    return DatePickerStyles(
+        disabledDateStyle: _disabledDateStyle,
+        currentDateStyle: _currentDateStyle,
+        displayedPeriodTitle: _displayedPeriodTitle,
+        selectedDateStyle: _selectedDateStyle,
+        selectedSingleDateDecoration: _selectedSingleDateDecoration,
+        defaultDateTextStyle: _defaultDateTextStyle,
+        dayHeaderStyle: _dayHeaderStyle,
+        dayHeaderStyleBuilder: dayHeaderStyleBuilder,
+        nextIcon: nextIcon,
+        prevIcon: prevIcon
+    );
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    if (other.runtimeType != runtimeType) return false;
+
+    return other is DatePickerStyles
+        && other.displayedPeriodTitle == displayedPeriodTitle
+        && other.currentDateStyle == currentDateStyle
+        && other.disabledDateStyle == disabledDateStyle
+        && other.selectedDateStyle == selectedDateStyle
+        && other.defaultDateTextStyle == defaultDateTextStyle
+        && other.selectedSingleDateDecoration == selectedSingleDateDecoration
+        && other.dayHeaderStyle == dayHeaderStyle
+        && other.dayHeaderStyleBuilder == dayHeaderStyleBuilder
+        && other.prevIcon == prevIcon
+        && other.nextIcon == nextIcon
+        && other.firstDayOfeWeekIndex == firstDayOfeWeekIndex;
+  }
+
+  @override
+  int get hashCode =>
+     hashValues(
+        displayedPeriodTitle,
+        currentDateStyle,
+        disabledDateStyle,
+        selectedDateStyle,
+        defaultDateTextStyle,
+        selectedSingleDateDecoration,
+        dayHeaderStyle,
+        dayHeaderStyleBuilder,
+        prevIcon,
+        nextIcon,
+        firstDayOfeWeekIndex
+    );
+
+  static bool _validateDayHeaderStyleBuilder(DayHeaderStyleBuilder builder) {
+    List<int> weekdays = const [0, 1, 2, 3, 4, 5, 6];
+
+    // ignore: avoid_types_on_closure_parameters
+    bool valid = weekdays.every((int weekday) => builder(weekday) != null);
+
+    return valid;
+  }
+
+  static bool _validateFirstDayOfWeek(int? index) {
+    if (index == null) return true;
+
+    bool valid = index >= 0 && index <= 6;
+
+    return valid;
+  }
+}
+
+/// Styles for date pickers which allow select some range
+/// (e.g. RangePicker, WeekPicker).
+@immutable
+class DatePickerRangeStyles extends DatePickerStyles {
+  /// Decoration for the first date of the selected range.
+  final BoxDecoration? selectedPeriodStartDecoration;
+
+  /// Text style for the first date of the selected range.
+  ///
+  /// If null - default [DatePickerStyles.selectedDateStyle] will be used.
+  final TextStyle? selectedPeriodStartTextStyle;
+
+  /// Decoration for the last date of the selected range.
+  final BoxDecoration? selectedPeriodLastDecoration;
+
+  /// Text style for the last date of the selected range.
+  ///
+  /// If null - default [DatePickerStyles.selectedDateStyle] will be used.
+  final TextStyle? selectedPeriodEndTextStyle;
+
+  /// Decoration for the date of the selected range
+  /// which is not first date and not end date of this range.
+  ///
+  /// If there is only one date selected
+  /// [DatePickerStyles.selectedSingleDateDecoration] will be used.
+  final BoxDecoration? selectedPeriodMiddleDecoration;
+
+  /// Text style for the middle date of the selected range.
+  ///
+  /// If null - default [DatePickerStyles.selectedDateStyle] will be used.
+  final TextStyle? selectedPeriodMiddleTextStyle;
+
+  /// Return new [DatePickerRangeStyles] object
+  /// where fields with null values set with defaults from given theme.
+  @override
+  DatePickerRangeStyles fulfillWithTheme(ThemeData theme) {
+    Color accentColor = theme.accentColor;
+
+    DatePickerStyles commonStyles = super.fulfillWithTheme(theme);
+
+    final BoxDecoration _selectedPeriodStartDecoration =
+        selectedPeriodStartDecoration ??
+            BoxDecoration(
+              color: accentColor,
+              borderRadius: const BorderRadius.only(
+                  topLeft: Radius.circular(10.0),
+                  bottomLeft: Radius.circular(10.0)),
+            );
+
+    final BoxDecoration _selectedPeriodLastDecoration =
+        selectedPeriodLastDecoration ??
+            BoxDecoration(
+              color: accentColor,
+              borderRadius: const BorderRadius.only(
+                  topRight: Radius.circular(10.0),
+                  bottomRight: Radius.circular(10.0)),
+            );
+
+    final BoxDecoration _selectedPeriodMiddleDecoration =
+        selectedPeriodMiddleDecoration ??
+            BoxDecoration(
+              color: accentColor,
+              shape: BoxShape.rectangle,
+            );
+
+    final TextStyle? _selectedPeriodStartTextStyle =
+        selectedPeriodStartTextStyle ?? commonStyles.selectedDateStyle;
+
+    final TextStyle? _selectedPeriodMiddleTextStyle =
+        selectedPeriodMiddleTextStyle ?? commonStyles.selectedDateStyle;
+
+    final TextStyle? _selectedPeriodEndTextStyle =
+        selectedPeriodEndTextStyle ?? commonStyles.selectedDateStyle;
+
+    return DatePickerRangeStyles(
+        disabledDateStyle: commonStyles.disabledDateStyle,
+        currentDateStyle: commonStyles.currentDateStyle,
+        displayedPeriodTitle: commonStyles.displayedPeriodTitle,
+        selectedDateStyle: commonStyles.selectedDateStyle,
+        selectedSingleDateDecoration: commonStyles.selectedSingleDateDecoration,
+        defaultDateTextStyle: commonStyles.defaultDateTextStyle,
+        dayHeaderStyle: commonStyles.dayHeaderStyle,
+        dayHeaderStyleBuilder: commonStyles.dayHeaderStyleBuilder,
+        firstDayOfWeekIndex: firstDayOfeWeekIndex,
+        selectedPeriodStartDecoration: _selectedPeriodStartDecoration,
+        selectedPeriodMiddleDecoration: _selectedPeriodMiddleDecoration,
+        selectedPeriodLastDecoration: _selectedPeriodLastDecoration,
+        selectedPeriodStartTextStyle: _selectedPeriodStartTextStyle,
+        selectedPeriodMiddleTextStyle: _selectedPeriodMiddleTextStyle,
+        selectedPeriodEndTextStyle: _selectedPeriodEndTextStyle,
+    );
+  }
+
+  /// Styles for the pickers that allows to select range ([RangePicker],
+  /// [WeekPicker]).
+  DatePickerRangeStyles({
+    displayedPeriodTitle,
+    currentDateStyle,
+    disabledDateStyle,
+    selectedDateStyle,
+    selectedSingleDateDecoration,
+    defaultDateTextStyle,
+    dayHeaderStyle,
+    dayHeaderStyleBuilder,
+    Widget nextIcon = const Icon(Icons.chevron_right),
+    Widget prevIcon = const Icon(Icons.chevron_left),
+    firstDayOfWeekIndex,
+    this.selectedPeriodLastDecoration,
+    this.selectedPeriodMiddleDecoration,
+    this.selectedPeriodStartDecoration,
+    this.selectedPeriodStartTextStyle,
+    this.selectedPeriodMiddleTextStyle,
+    this.selectedPeriodEndTextStyle,
+  }) : super(
+            displayedPeriodTitle: displayedPeriodTitle,
+            currentDateStyle: currentDateStyle,
+            disabledDateStyle: disabledDateStyle,
+            selectedDateStyle: selectedDateStyle,
+            selectedSingleDateDecoration: selectedSingleDateDecoration,
+            defaultDateTextStyle: defaultDateTextStyle,
+            dayHeaderStyle: dayHeaderStyle,
+            dayHeaderStyleBuilder: dayHeaderStyleBuilder,
+            nextIcon: nextIcon,
+            prevIcon: prevIcon,
+            firstDayOfeWeekIndex: firstDayOfWeekIndex
+       );
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    if (other.runtimeType != runtimeType) return false;
+
+    return other is DatePickerRangeStyles
+        && other.selectedPeriodStartDecoration == selectedPeriodStartDecoration
+        && other.selectedPeriodStartTextStyle == selectedPeriodStartTextStyle
+        && other.selectedPeriodLastDecoration == selectedPeriodLastDecoration
+        && other.selectedPeriodEndTextStyle == selectedPeriodEndTextStyle
+        && other.selectedPeriodMiddleDecoration ==selectedPeriodMiddleDecoration
+        && other.selectedPeriodMiddleTextStyle == selectedPeriodMiddleTextStyle
+        && other.displayedPeriodTitle == displayedPeriodTitle
+        && other.currentDateStyle == currentDateStyle
+        && other.disabledDateStyle == disabledDateStyle
+        && other.selectedDateStyle == selectedDateStyle
+        && other.defaultDateTextStyle == defaultDateTextStyle
+        && other.selectedSingleDateDecoration == selectedSingleDateDecoration
+        && other.dayHeaderStyle == dayHeaderStyle
+        && other.dayHeaderStyleBuilder == dayHeaderStyleBuilder
+        && other.prevIcon == prevIcon
+        && other.nextIcon == nextIcon
+        && other.firstDayOfeWeekIndex == firstDayOfeWeekIndex;
+  }
+
+  @override
+  int get hashCode =>
+     hashValues(
+      selectedPeriodStartDecoration,
+      selectedPeriodStartTextStyle,
+      selectedPeriodLastDecoration,
+      selectedPeriodEndTextStyle,
+      selectedPeriodMiddleDecoration,
+      selectedPeriodMiddleTextStyle,
+      displayedPeriodTitle,
+      currentDateStyle,
+      disabledDateStyle,
+      selectedDateStyle,
+      defaultDateTextStyle,
+      selectedSingleDateDecoration,
+      dayHeaderStyle,
+      dayHeaderStyleBuilder,
+      prevIcon,
+      nextIcon,
+      firstDayOfeWeekIndex
+    );
+}
+
+
+/// User styles for the day header in date picker.
+@immutable
+class DayHeaderStyle {
+  /// If null - textTheme.caption from the Theme will be used.
+  final TextStyle? textStyle;
+
+  /// If null - no decoration will be applied for the day header;
+  final BoxDecoration? decoration;
+
+  /// Creates styles for the day headers in date pickers.
+  ///
+  /// See also:
+  /// * [DatePickerStyles.dayHeaderStyleBuilder]
+  const DayHeaderStyle({
+    this.textStyle,
+    this.decoration
+  });
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    if (other.runtimeType != runtimeType) return false;
+
+    return other is DayHeaderStyle
+        && other.textStyle == textStyle
+        && other.decoration == decoration;
+  }
+
+  @override
+  int get hashCode => hashValues(
+      textStyle,
+      decoration
+    );
+}

flutter_date_pickers-master/lib/src/day_based_changable_picker.dart

@@ -0,0 +1,363 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+
+import 'package:intl/intl.dart' as intl;
+
+import 'basic_day_based_widget.dart';
+import 'date_picker_keys.dart';
+import 'date_picker_styles.dart';
+import 'day_based_changeable_picker_presenter.dart';
+import 'day_picker_selection.dart';
+import 'day_type.dart';
+import 'event_decoration.dart';
+import 'i_selectable_picker.dart';
+import 'layout_settings.dart';
+import 'month_navigation_row.dart';
+import 'semantic_sorting.dart';
+import 'typedefs.dart';
+import 'utils.dart';
+
+
+const Locale _defaultLocale = Locale('en', 'US');
+
+/// Date picker based on [DayBasedPicker] picker (for days, weeks, ranges).
+/// Allows select previous/next month.
+class DayBasedChangeablePicker<T> extends StatefulWidget {
+  /// The currently selected date.
+  ///
+  /// This date is highlighted in the picker.
+  final DayPickerSelection selection;
+
+  /// Called when the user picks a new T.
+  final ValueChanged<T> onChanged;
+
+  /// Called when the error was thrown after user selection.
+  final OnSelectionError? onSelectionError;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// Date for defining what month should be shown initially.
+  ///
+  /// Default value is [selection.earliest].
+  final DateTime initiallyShowDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles datePickerStyles;
+
+  /// Some keys useful for integration tests
+  final DatePickerKeys? datePickerKeys;
+
+  /// Logic for date selections.
+  final ISelectablePicker<T> selectablePicker;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overridden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  /// Called when the user changes the month
+  final ValueChanged<DateTime>? onMonthChanged;
+
+  /// Create picker with option to change month.
+  DayBasedChangeablePicker(
+      {Key? key,
+      required this.selection,
+      required this.onChanged,
+      required this.firstDate,
+      required this.lastDate,
+      required this.datePickerLayoutSettings,
+      required this.datePickerStyles,
+      required this.selectablePicker,
+      DateTime? initiallyShownDate,
+      this.datePickerKeys,
+      this.onSelectionError,
+      this.eventDecorationBuilder,
+      this.onMonthChanged})
+      : initiallyShowDate = initiallyShownDate ?? selection.earliest,
+        super(key: key);
+
+  @override
+  State<DayBasedChangeablePicker<T>> createState() =>
+      _DayBasedChangeablePickerState<T>();
+}
+
+// todo: Check initial selection and call onSelectionError in case it has error
+// todo: (ISelectablePicker.curSelectionIsCorrupted);
+class _DayBasedChangeablePickerState<T>
+    extends State<DayBasedChangeablePicker<T>> {
+  DateTime _todayDate = DateTime.now();
+
+  Locale curLocale = _defaultLocale;
+
+  MaterialLocalizations localizations = _defaultLocalizations;
+
+  PageController _dayPickerController = PageController();
+
+  // Styles from widget fulfilled with current Theme.
+  DatePickerRangeStyles _resultStyles = DatePickerRangeStyles();
+
+  DayBasedChangeablePickerPresenter _presenter = _defaultPresenter;
+
+  Timer? _timer;
+  StreamSubscription<T>? _changesSubscription;
+
+  @override
+  void initState() {
+    super.initState();
+
+    // Initially display the pre-selected date.
+    final int monthPage = _getInitPage();
+    _dayPickerController = PageController(initialPage: monthPage);
+
+    _changesSubscription = widget.selectablePicker.onUpdate
+        .listen((newSelectedDate) => widget.onChanged(newSelectedDate))
+          ..onError((e) => widget.onSelectionError != null
+              ? widget.onSelectionError!.call(e)
+              : print(e.toString()));
+
+    _updateCurrentDate();
+    _initPresenter();
+  }
+
+  @override
+  void didUpdateWidget(DayBasedChangeablePicker<T> oldWidget) {
+    super.didUpdateWidget(oldWidget);
+
+    if (widget.datePickerStyles != oldWidget.datePickerStyles) {
+      final ThemeData theme = Theme.of(context);
+      _resultStyles = widget.datePickerStyles.fulfillWithTheme(theme);
+    }
+
+    if (widget.selectablePicker != oldWidget.selectablePicker) {
+      _changesSubscription = widget.selectablePicker.onUpdate
+          .listen((newSelectedDate) => widget.onChanged(newSelectedDate))
+            ..onError((e) => widget.onSelectionError != null
+                ? widget.onSelectionError!.call(e)
+                : print(e.toString()));
+    }
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    curLocale = Localizations.localeOf(context);
+
+    MaterialLocalizations? curLocalizations =
+        Localizations.of<MaterialLocalizations>(context, MaterialLocalizations);
+    if (curLocalizations != null && localizations != curLocalizations) {
+      localizations = curLocalizations;
+      _initPresenter();
+    }
+
+    final ThemeData theme = Theme.of(context);
+    _resultStyles = widget.datePickerStyles.fulfillWithTheme(theme);
+  }
+
+  @override
+  // ignore: prefer_expression_function_bodies
+  Widget build(BuildContext context) {
+    return SizedBox(
+        width: widget.datePickerLayoutSettings.monthPickerPortraitWidth,
+        height: widget.datePickerLayoutSettings.maxDayPickerHeight,
+        child: Column(
+          children: <Widget>[
+            widget.datePickerLayoutSettings.hideMonthNavigationRow
+                ? const SizedBox()
+                : SizedBox(
+                    height: widget.datePickerLayoutSettings.dayPickerRowHeight,
+                    child: Padding(
+                        //match _DayPicker main layout padding
+                        padding: widget.datePickerLayoutSettings.contentPadding,
+                        child: _buildMonthNavigationRow()),
+                  ),
+            Expanded(
+              child: Semantics(
+                sortKey: MonthPickerSortKey.calendar,
+                child: _buildDayPickerPageView(),
+              ),
+            ),
+          ],
+        ));
+  }
+
+  @override
+  void dispose() {
+    _timer?.cancel();
+    _dayPickerController.dispose();
+    _changesSubscription?.cancel();
+    widget.selectablePicker.dispose();
+    _presenter.dispose();
+    super.dispose();
+  }
+
+  void _updateCurrentDate() {
+    _todayDate = DateTime.now();
+    final DateTime tomorrow =
+        DateTime(_todayDate.year, _todayDate.month, _todayDate.day + 1);
+    Duration timeUntilTomorrow = tomorrow.difference(_todayDate);
+    timeUntilTomorrow +=
+        const Duration(seconds: 1); // so we don't miss it by rounding
+    _timer?.cancel();
+    _timer = Timer(timeUntilTomorrow, () {
+      setState(_updateCurrentDate);
+    });
+  }
+
+  // ignore: prefer_expression_function_bodies
+  Widget _buildMonthNavigationRow() {
+    return StreamBuilder<DayBasedChangeablePickerState>(
+        stream: _presenter.data,
+        initialData: _presenter.lastVal,
+        builder: (context, snapshot) {
+          if (!snapshot.hasData) {
+            return const SizedBox();
+          }
+
+          DayBasedChangeablePickerState state = snapshot.data!;
+
+          return MonthNavigationRow(
+            previousPageIconKey: widget.datePickerKeys?.previousPageIconKey,
+            nextPageIconKey: widget.datePickerKeys?.nextPageIconKey,
+            previousMonthTooltip: state.prevTooltip,
+            nextMonthTooltip: state.nextTooltip,
+            onPreviousMonthTapped:
+                state.isFirstMonth ? null : _presenter.gotoPrevMonth,
+            onNextMonthTapped:
+                state.isLastMonth ? null : _presenter.gotoNextMonth,
+            title: Text(
+              state.curMonthDis,
+              key: widget.datePickerKeys?.selectedPeriodKeys,
+              style: _resultStyles.displayedPeriodTitle,
+            ),
+            nextIcon: widget.datePickerStyles.nextIcon,
+            prevIcon: widget.datePickerStyles.prevIcon,
+          );
+        });
+  }
+
+  Widget _buildDayPickerPageView() => PageView.builder(
+        controller: _dayPickerController,
+        scrollDirection: Axis.horizontal,
+        itemCount:
+            DatePickerUtils.monthDelta(widget.firstDate, widget.lastDate) + 1,
+        itemBuilder: _buildCalendar,
+        onPageChanged: _handleMonthPageChanged,
+      );
+
+  Widget _buildCalendar(BuildContext context, int index) {
+    final DateTime targetDate =
+        DatePickerUtils.addMonthsToMonthDate(widget.firstDate, index);
+
+    return DayBasedPicker(
+      key: ValueKey<DateTime>(targetDate),
+      selectablePicker: widget.selectablePicker,
+      currentDate: _todayDate,
+      firstDate: widget.firstDate,
+      lastDate: widget.lastDate,
+      displayedMonth: targetDate,
+      datePickerLayoutSettings: widget.datePickerLayoutSettings,
+      selectedPeriodKey: widget.datePickerKeys?.selectedPeriodKeys,
+      datePickerStyles: _resultStyles,
+      eventDecorationBuilder: widget.eventDecorationBuilder,
+      localizations: localizations,
+    );
+  }
+
+  // Returns appropriate date to be shown for init.
+  // If [widget.initiallyShowDate] is out of bounds [widget.firstDate]
+  // - [widget.lastDate], nearest bound will be used.
+  DateTime _getCheckedInitialDate() {
+    DateTime initiallyShowDateChecked = widget.initiallyShowDate;
+    if (initiallyShowDateChecked.isBefore(widget.firstDate)) {
+      initiallyShowDateChecked = widget.firstDate;
+    }
+
+    if (initiallyShowDateChecked.isAfter(widget.lastDate)) {
+      initiallyShowDateChecked = widget.lastDate;
+    }
+
+    return initiallyShowDateChecked;
+  }
+
+  int _getInitPage() {
+    final initialDate = _getCheckedInitialDate();
+    int initPage = DatePickerUtils.monthDelta(
+        widget.firstDate, initialDate
+    );
+
+    return initPage;
+  }
+
+  void _initPresenter() {
+    _presenter.dispose();
+
+    _presenter = DayBasedChangeablePickerPresenter(
+        firstDate: widget.firstDate,
+        lastDate: widget.lastDate,
+        localizations: localizations,
+        showPrevMonthDates: widget.datePickerLayoutSettings.showPrevMonthEnd,
+        showNextMonthDates: widget.datePickerLayoutSettings.showNextMonthStart,
+        firstDayOfWeekIndex: widget.datePickerStyles.firstDayOfeWeekIndex);
+    _presenter.data.listen(_onStateChanged);
+
+    // date used to define what month should be shown
+    DateTime initSelection = _getCheckedInitialDate();
+
+    // Give information about initial selection to presenter.
+    // It should be done after first frame when PageView is already created.
+    // Otherwise event from presenter will cause a error.
+    WidgetsBinding.instance!.addPostFrameCallback((_) {
+      _presenter.setSelectedDate(initSelection);
+    });
+  }
+
+  void _onStateChanged(DayBasedChangeablePickerState newState) {
+    DateTime newMonth = newState.currentMonth;
+    final int monthPage =
+        DatePickerUtils.monthDelta(widget.firstDate, newMonth);
+    _dayPickerController.animateToPage(monthPage,
+        duration: const Duration(milliseconds: 200), curve: Curves.easeInOut);
+  }
+
+  void _handleMonthPageChanged(int monthPage) {
+    DateTime firstMonth = widget.firstDate;
+    DateTime newMonth = DateTime(firstMonth.year, firstMonth.month + monthPage);
+    _presenter.changeMonth(newMonth);
+
+    widget.onMonthChanged?.call(newMonth);
+  }
+
+  static MaterialLocalizations get _defaultLocalizations =>
+      MaterialLocalizationEn(
+        twoDigitZeroPaddedFormat:
+            intl.NumberFormat('00', _defaultLocale.toString()),
+        fullYearFormat: intl.DateFormat.y(_defaultLocale.toString()),
+        longDateFormat: intl.DateFormat.yMMMMEEEEd(_defaultLocale.toString()),
+        shortMonthDayFormat: intl.DateFormat.MMMd(_defaultLocale.toString()),
+        decimalFormat:
+            intl.NumberFormat.decimalPattern(_defaultLocale.toString()),
+        shortDateFormat: intl.DateFormat.yMMMd(_defaultLocale.toString()),
+        mediumDateFormat: intl.DateFormat.MMMEd(_defaultLocale.toString()),
+        compactDateFormat: intl.DateFormat.yMd(_defaultLocale.toString()),
+        yearMonthFormat: intl.DateFormat.yMMMM(_defaultLocale.toString()),
+      );
+
+  static DayBasedChangeablePickerPresenter get _defaultPresenter =>
+      DayBasedChangeablePickerPresenter(
+          firstDate: DateTime.now(),
+          lastDate: DateTime.now(),
+          localizations: _defaultLocalizations,
+          showPrevMonthDates: false,
+          showNextMonthDates: false,
+          firstDayOfWeekIndex: 1);
+}

flutter_date_pickers-master/lib/src/day_based_changeable_picker_presenter.dart

@@ -0,0 +1,177 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+import 'day_based_changable_picker.dart';
+import 'utils.dart';
+
+/// Presenter for [DayBasedChangeablePicker] to handle month changes.
+class DayBasedChangeablePickerPresenter {
+  /// First date user can select.
+  final DateTime firstDate;
+
+  /// Last date user can select.
+  final DateTime lastDate;
+  
+  /// Localization.
+  final MaterialLocalizations localizations;
+  
+  /// If empty day cells before 1st day of showing month should be filled with
+  /// date from the last week of the previous month.
+  final bool showPrevMonthDates;
+
+  /// If empty day cells after last day of showing month should be filled with
+  /// date from the first week of the next month.
+  final bool showNextMonthDates;
+  
+  /// Index of the first day in week.
+  /// 0 is Sunday, 6 is Saturday.
+  final int firstDayOfWeekIndex;
+  
+  /// View model stream for the [DayBasedChangeablePicker].
+  Stream<DayBasedChangeablePickerState> get data => _controller.stream;
+
+  /// Last view model state of the [DayBasedChangeablePicker].
+  DayBasedChangeablePickerState? get lastVal => _lastVal;
+
+  /// Creates presenter to use for [DayBasedChangeablePicker].
+  DayBasedChangeablePickerPresenter({
+    required this.firstDate,
+    required this.lastDate,
+    required this.localizations,
+    required this.showPrevMonthDates,
+    required this.showNextMonthDates,
+    int? firstDayOfWeekIndex
+  }): firstDayOfWeekIndex = firstDayOfWeekIndex
+          ?? localizations.firstDayOfWeekIndex;
+
+  /// Update state according to the [selectedDate] if it needs.
+  void setSelectedDate(DateTime selectedDate) {
+    // bool firstAndLastNotNull = _firstShownDate != null
+    //     && _lastShownDate != null;
+    //
+    // bool selectedOnCurPage =  firstAndLastNotNull
+    //     && !selectedDate.isBefore(_firstShownDate)
+    //     && !selectedDate.isAfter(_lastShownDate);
+    // if (selectedOnCurPage) return;
+
+    changeMonth(selectedDate);
+  }
+
+  /// Update state to show previous month.
+  void gotoPrevMonth() {
+    DateTime oldCur = _lastVal!.currentMonth;
+    DateTime newCurDate = DateTime(oldCur.year, oldCur.month - 1);
+
+    changeMonth(newCurDate);
+  }
+
+  /// Update state to show next month.
+  void gotoNextMonth() {
+    DateTime oldCur = _lastVal!.currentMonth;
+    DateTime newCurDate = DateTime(oldCur.year, oldCur.month + 1);
+
+    changeMonth(newCurDate);
+  }
+
+  /// Update state to change month to the [newMonth].
+  void changeMonth(DateTime newMonth) {
+    bool sameMonth = _lastVal != null
+        && DatePickerUtils.sameMonth(_lastVal!.currentMonth, newMonth);
+    if (sameMonth) return;
+
+    int monthPage = DatePickerUtils.monthDelta(firstDate, newMonth);
+    DateTime prevMonth = DatePickerUtils
+        .addMonthsToMonthDate(firstDate, monthPage - 1);
+
+    DateTime curMonth = DatePickerUtils
+        .addMonthsToMonthDate(firstDate, monthPage);
+
+    DateTime nextMonth = DatePickerUtils
+        .addMonthsToMonthDate(firstDate, monthPage + 1);
+
+    String prevMonthStr = localizations.formatMonthYear(prevMonth);
+    String curMonthStr = localizations.formatMonthYear(curMonth);
+    String nextMonthStr = localizations.formatMonthYear(nextMonth);
+
+    bool isFirstMonth = DatePickerUtils.sameMonth(curMonth, firstDate);
+    bool isLastMonth = DatePickerUtils.sameMonth(curMonth, lastDate);
+
+    String? prevTooltip = isFirstMonth
+        ? null
+        : "${localizations.previousMonthTooltip} $prevMonthStr";
+
+    String? nextTooltip = isLastMonth
+        ? null
+        : "${localizations.nextMonthTooltip} $nextMonthStr";
+
+    DayBasedChangeablePickerState newState = DayBasedChangeablePickerState(
+        currentMonth: curMonth,
+        curMonthDis: curMonthStr,
+        prevMonthDis: prevMonthStr,
+        nextMonthDis: nextMonthStr,
+        prevTooltip: prevTooltip,
+        nextTooltip: nextTooltip,
+        isFirstMonth: isFirstMonth,
+        isLastMonth: isLastMonth
+    );
+
+    _updateState(newState);
+  }
+
+  /// Closes controller.
+  void dispose () {
+    _controller.close();
+  }
+
+  void _updateState(DayBasedChangeablePickerState newState) {
+    _lastVal = newState;
+    _controller.add(newState);
+  }
+
+  final StreamController<DayBasedChangeablePickerState> _controller =
+    StreamController.broadcast();
+
+  DayBasedChangeablePickerState? _lastVal;
+}
+
+
+/// View Model for the [DayBasedChangeablePicker].
+class DayBasedChangeablePickerState {
+
+  /// Display name of the current month.
+  final String curMonthDis;
+
+  /// Display name of the previous month.
+  final String prevMonthDis;
+
+  /// Display name of the next month.
+  final String nextMonthDis;
+
+  /// Tooltip for the previous month icon.
+  final String? prevTooltip;
+
+  /// Tooltip for the next month icon.
+  final String? nextTooltip;
+
+  /// Tooltip for the current month icon.
+  final DateTime currentMonth;
+
+  /// If selected month is the month contains last date user can select.
+  final bool isLastMonth;
+
+  /// If selected month is the month contains first date user can select.
+  final bool isFirstMonth;
+
+  /// Creates view model for the [DayBasedChangeablePicker].
+  DayBasedChangeablePickerState({
+    required this.curMonthDis,
+    required this.prevMonthDis,
+    required this.nextMonthDis,
+    required this.currentMonth,
+    required this.isLastMonth,
+    required this.isFirstMonth,
+    this.prevTooltip,
+    this.nextTooltip,
+  });
+}

flutter_date_pickers-master/lib/src/day_picker.dart

@@ -0,0 +1,189 @@
+import 'package:flutter/material.dart';
+
+import 'date_picker_keys.dart';
+import 'date_picker_styles.dart';
+import 'day_based_changable_picker.dart';
+import 'day_picker_selection.dart';
+import 'day_type.dart';
+import 'event_decoration.dart';
+import 'i_selectable_picker.dart';
+import 'layout_settings.dart';
+
+/// Date picker for selection one day.
+class DayPicker<T extends Object> extends StatelessWidget {
+  DayPicker._({Key? key,
+    required this.onChanged,
+    required this.firstDate,
+    required this.lastDate,
+    required this.selectionLogic,
+    required this.selection,
+    this.initiallyShowDate,
+    this.datePickerLayoutSettings = const DatePickerLayoutSettings(),
+    this.datePickerStyles,
+    this.datePickerKeys,
+    this.selectableDayPredicate,
+    this.eventDecorationBuilder,
+    this.onMonthChanged}) : super(key: key);
+
+  /// Creates a day picker where only one single day can be selected.
+  ///
+  /// See also:
+  /// * [DayPicker.multi] - day picker where many single days can be selected.
+  static DayPicker<DateTime> single({
+    Key? key,
+    required DateTime selectedDate,
+    required ValueChanged<DateTime> onChanged,
+    required DateTime firstDate,
+    required DateTime lastDate,
+    DatePickerLayoutSettings datePickerLayoutSettings
+      = const DatePickerLayoutSettings(),
+    DateTime? initiallyShowDate,
+    DatePickerRangeStyles? datePickerStyles,
+    DatePickerKeys? datePickerKeys,
+    SelectableDayPredicate? selectableDayPredicate,
+    EventDecorationBuilder? eventDecorationBuilder,
+    ValueChanged<DateTime>? onMonthChanged
+  })
+  {
+    assert(!firstDate.isAfter(lastDate));
+    assert(!lastDate.isBefore(firstDate));
+    assert(!selectedDate.isBefore(firstDate));
+    assert(!selectedDate.isAfter(lastDate));
+    assert(initiallyShowDate == null
+        || !initiallyShowDate.isAfter(lastDate));
+    assert(initiallyShowDate == null
+    || !initiallyShowDate.isBefore(firstDate));
+
+    final selection = DayPickerSingleSelection(selectedDate);
+    final selectionLogic = DaySelectable(
+    selectedDate, firstDate, lastDate,
+    selectableDayPredicate: selectableDayPredicate);
+
+    return DayPicker<DateTime>._(
+        onChanged: onChanged,
+        firstDate: firstDate,
+        lastDate: lastDate,
+        initiallyShowDate: initiallyShowDate,
+        selectionLogic: selectionLogic,
+        selection: selection,
+        eventDecorationBuilder: eventDecorationBuilder,
+        onMonthChanged: onMonthChanged,
+        selectableDayPredicate: selectableDayPredicate,
+        datePickerKeys: datePickerKeys,
+        datePickerStyles: datePickerStyles,
+        datePickerLayoutSettings: datePickerLayoutSettings,
+    );
+  }
+
+
+  /// Creates a day picker  where many single days can be selected.
+  ///
+  /// See also:
+  /// * [DayPicker.single] - day picker where only one single day
+  /// can be selected.
+  static DayPicker<List<DateTime>> multi({Key? key,
+    required List<DateTime> selectedDates,
+    required ValueChanged<List<DateTime>> onChanged,
+    required DateTime firstDate,
+    required DateTime lastDate,
+    DatePickerLayoutSettings datePickerLayoutSettings
+      = const DatePickerLayoutSettings(),
+    DateTime? initiallyShowDate,
+    DatePickerRangeStyles? datePickerStyles,
+    DatePickerKeys? datePickerKeys,
+    SelectableDayPredicate? selectableDayPredicate,
+    EventDecorationBuilder? eventDecorationBuilder,
+    ValueChanged<DateTime>? onMonthChanged})
+  {
+    assert(!firstDate.isAfter(lastDate));
+    assert(!lastDate.isBefore(firstDate));
+    assert(initiallyShowDate == null
+        || !initiallyShowDate.isAfter(lastDate));
+    assert(initiallyShowDate == null
+    || !initiallyShowDate.isBefore(lastDate));
+
+    final selection =  DayPickerMultiSelection(selectedDates);
+    final selectionLogic =  DayMultiSelectable(
+        selectedDates, firstDate, lastDate,
+        selectableDayPredicate: selectableDayPredicate);
+
+    return DayPicker<List<DateTime>>._(
+      onChanged: onChanged,
+      firstDate: firstDate,
+      lastDate: lastDate,
+      initiallyShowDate: initiallyShowDate,
+      selectionLogic: selectionLogic,
+      selection: selection,
+      eventDecorationBuilder: eventDecorationBuilder,
+      onMonthChanged: onMonthChanged,
+      selectableDayPredicate: selectableDayPredicate,
+      datePickerKeys: datePickerKeys,
+      datePickerStyles: datePickerStyles,
+      datePickerLayoutSettings: datePickerLayoutSettings,
+    );
+  }
+
+  /// The currently selected date.
+  ///
+  /// This date is highlighted in the picker.
+  final DayPickerSelection selection;
+
+  /// Called when the user picks a day.
+  final ValueChanged<T> onChanged;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// Date for defining what month should be shown initially.
+  ///
+  /// In case of null earliest of the [selection] will be shown.
+  final DateTime? initiallyShowDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles? datePickerStyles;
+
+  /// Some keys useful for integration tests
+  final DatePickerKeys? datePickerKeys;
+
+  /// Function returns if day can be selected or not.
+  ///
+  /// If null
+  final SelectableDayPredicate? selectableDayPredicate;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overriden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  // Called when the user changes the month.
+  /// New DateTime object represents first day of new month and 00:00 time.
+  final ValueChanged<DateTime>? onMonthChanged;
+
+  /// Logic to handle user's selections.
+  final ISelectablePicker<T> selectionLogic;
+  
+  @override
+  // ignore: prefer_expression_function_bodies
+  Widget build(BuildContext context) {
+    return DayBasedChangeablePicker<T>(
+      selectablePicker: selectionLogic,
+      selection: selection,
+      firstDate: firstDate,
+      lastDate: lastDate,
+      initiallyShownDate: initiallyShowDate,
+      onChanged: onChanged,
+      datePickerLayoutSettings: datePickerLayoutSettings,
+      datePickerStyles: datePickerStyles ?? DatePickerRangeStyles(),
+      datePickerKeys: datePickerKeys,
+      eventDecorationBuilder: eventDecorationBuilder,
+      onMonthChanged: onMonthChanged,
+    );
+  }
+}

flutter_date_pickers-master/lib/src/day_picker_selection.dart

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+import 'date_period.dart';
+import 'utils.dart';
+
+/// Base class for day based pickers selection.
+abstract class DayPickerSelection {
+
+  /// If this is before [dateTime].
+  bool isBefore(DateTime dateTime);
+
+  /// If this is after [dateTime].
+  bool isAfter(DateTime dateTime);
+
+  /// Returns earliest [DateTime] in this selection.
+  DateTime get earliest;
+
+  /// If this selection is empty.
+  bool get isEmpty;
+
+  /// If this selection is not empty.
+  bool get isNotEmpty;
+
+  /// Constructor to allow children to have constant constructor.
+  const DayPickerSelection();
+}
+
+/// Selection with only one selected date.
+///
+/// See also:
+/// * [DayPickerMultiSelection] - selection with one or many single dates.
+/// * [DayPickerRangeSelection] - date period selection.
+class DayPickerSingleSelection extends DayPickerSelection {
+
+  /// Selected date.
+  final DateTime selectedDate;
+
+  /// Creates selection with only one selected date.
+  const DayPickerSingleSelection(this.selectedDate)
+      : assert(selectedDate != null);
+
+  @override
+  bool isAfter(DateTime dateTime) => selectedDate.isAfter(dateTime);
+
+  @override
+  bool isBefore(DateTime dateTime) => selectedDate.isAfter(dateTime);
+
+  @override
+  DateTime get earliest => selectedDate;
+
+  @override
+  bool get isEmpty => selectedDate == null;
+
+  @override
+  bool get isNotEmpty => selectedDate != null;
+}
+
+
+/// Selection with one or many single dates.
+///
+/// See also:
+/// * [DayPickerSingleSelection] - selection with only one selected date.
+/// * [DayPickerRangeSelection] - date period selection.
+class DayPickerMultiSelection extends DayPickerSelection {
+
+  /// List of the selected dates.
+  final List<DateTime> selectedDates;
+
+  /// Selection with one or many single dates.
+  DayPickerMultiSelection(this.selectedDates)
+      : assert(selectedDates != null);
+
+
+  @override
+  bool isAfter(DateTime dateTime)
+  => selectedDates.every((d) => d.isAfter(dateTime));
+
+  @override
+  bool isBefore(DateTime dateTime)
+  => selectedDates.every((d) => d.isBefore(dateTime));
+
+  @override
+  DateTime get earliest => DatePickerUtils.getEarliestFromList(selectedDates);
+
+  @override
+  bool get isEmpty => selectedDates.isEmpty;
+
+  @override
+  bool get isNotEmpty => selectedDates.isNotEmpty;
+}
+
+
+
+/// Date period selection.
+///
+/// See also:
+/// * [DayPickerSingleSelection] - selection with only one selected date.
+/// * [DayPickerMultiSelection] - selection with one or many single dates.
+class DayPickerRangeSelection extends DayPickerSelection {
+
+  /// Selected period.
+  final DatePeriod selectedRange;
+
+  /// Date period selection.
+  const DayPickerRangeSelection(this.selectedRange)
+      : assert(selectedRange != null);
+
+  @override
+  DateTime get earliest => selectedRange.start;
+
+  @override
+  bool isAfter(DateTime dateTime) => selectedRange.start.isAfter(dateTime);
+
+  @override
+  bool isBefore(DateTime dateTime) => selectedRange.end.isBefore(dateTime);
+
+  @override
+  bool get isEmpty => selectedRange == null;
+
+  @override
+  bool get isNotEmpty => selectedRange != null;
+}

flutter_date_pickers-master/lib/src/day_type.dart

@@ -0,0 +1,20 @@
+/// Type of the day in day based date picker.
+enum DayType {
+  /// start of the selected period
+  start,
+
+  /// middle of the selected period
+  middle,
+
+  /// end of the selected period
+  end,
+
+  /// selected single day
+  single,
+
+  /// disabled day
+  disabled,
+
+  /// not selected day (but not disabled)
+  notSelected
+}

flutter_date_pickers-master/lib/src/event_decoration.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/widgets.dart';
+
+import 'day_picker.dart';
+import 'range_picker.dart';
+import 'week_picker.dart';
+
+
+/// Signature for function which is used to set set specific decoration for
+/// some days in [DayPicker], [WeekPicker] and [RangePicker].
+///
+/// See also:
+/// * [DayPicker.eventDecorationBuilder]
+/// * [WeekPicker.eventDecorationBuilder]
+/// * [RangePicker.eventDecorationBuilder]
+typedef EventDecorationBuilder = EventDecoration? Function(DateTime date);
+
+
+/// Class to store styles for event (specific day in the date picker).
+@immutable
+class EventDecoration {
+
+  /// Cell decoration for the specific day in the date picker (event).
+  final BoxDecoration? boxDecoration;
+
+  /// Style for number of the specific day in the date picker (event).
+  final TextStyle? textStyle;
+
+  /// Creates decoration for special day.
+  ///
+  /// Used for [EventDecorationBuilder] function which is usually passed to
+  /// [DayPicker.eventDecorationBuilder], [WeekPicker.eventDecorationBuilder]
+  /// and [RangePicker.eventDecorationBuilder] to set specific decoration for
+  /// some days.
+  const EventDecoration({this.boxDecoration, this.textStyle});
+}

flutter_date_pickers-master/lib/src/i_selectable_picker.dart

@@ -0,0 +1,537 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+import 'date_period.dart';
+import 'day_picker.dart' as day_picker;
+import 'day_type.dart';
+import 'range_picker.dart';
+import 'unselectable_period_error.dart';
+import 'utils.dart';
+
+/// Interface for selection logic of the different date pickers.
+///
+/// T - is selection type.
+abstract class ISelectablePicker<T> {
+  /// The earliest date the user is permitted to pick.
+  /// (only year, month and day matter, time doesn't matter)
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  /// (only year, month and day matter, time doesn't matter)
+  final DateTime lastDate;
+
+  /// Function returns if day can be selected or not.
+  final SelectableDayPredicate _selectableDayPredicate;
+
+  /// StreamController for new selection (T).
+  @protected
+  StreamController<T> onUpdateController = StreamController<T>.broadcast();
+
+  /// Stream with new selected (T) event.
+  ///
+  /// Throws [UnselectablePeriodException]
+  /// if there is any custom disabled date in selected.
+  Stream<T> get onUpdate => onUpdateController.stream;
+
+  /// Constructor with required fields that used in non-abstract methods
+  /// ([isDisabled]).
+  ISelectablePicker(this.firstDate, this.lastDate,
+      {SelectableDayPredicate? selectableDayPredicate})
+      : _selectableDayPredicate =
+            selectableDayPredicate ?? _defaultSelectableDayPredicate;
+
+  /// If current selection exists and includes day/days that can't be selected
+  /// according to the [_selectableDayPredicate]'
+  bool get curSelectionIsCorrupted;
+
+  /// Returns [DayType] for given [day].
+  DayType getDayType(DateTime day);
+
+  /// Call when user tap on the day cell.
+  void onDayTapped(DateTime selectedDate);
+
+  /// Returns if given day is disabled.
+  ///
+  /// Returns weather given day before the beginning of the [firstDate]
+  /// or after the end of the [lastDate].
+  ///
+  /// If [_selectableDayPredicate] is set checks it as well.
+  @protected
+  bool isDisabled(DateTime day) {
+    final DateTime beginOfTheFirstDay =
+        DatePickerUtils.startOfTheDay(firstDate);
+    final DateTime endOfTheLastDay = DatePickerUtils.endOfTheDay(lastDate);
+    final bool customDisabled =
+        _selectableDayPredicate != null ? !_selectableDayPredicate(day) : false;
+
+    return day.isAfter(endOfTheLastDay) ||
+        day.isBefore(beginOfTheFirstDay) ||
+        customDisabled;
+  }
+
+  /// Closes [onUpdateController].
+  /// After it [onUpdateController] can't get new events.
+  void dispose() {
+    onUpdateController.close();
+  }
+
+  static bool _defaultSelectableDayPredicate(_) => true;
+}
+
+/// Selection logic for WeekPicker.
+class WeekSelectable extends ISelectablePicker<DatePeriod> {
+  /// Initialized in ctor body.
+  late DateTime _firstDayOfSelectedWeek;
+
+  /// Initialized in ctor body.
+  late DateTime _lastDayOfSelectedWeek;
+
+  // It is int from 0 to 6 where 0 points to Sunday and 6 points to Saturday.
+  // According to MaterialLocalization.firstDayOfWeekIndex.
+  final int _firstDayOfWeekIndex;
+
+  @override
+  bool get curSelectionIsCorrupted => _checkCurSelection();
+
+  /// Creates selection logic for WeekPicker.
+  ///
+  /// Entire week will be selected if
+  /// * it is between [firstDate] and [lastDate]
+  /// * it doesn't include unselectable days according to the
+  ///   [selectableDayPredicate]
+  ///
+  /// If one or more days of the week are before [firstDate]
+  /// first selection date will be the same as [firstDate].
+  ///
+  /// If one or more days of the week are after [lastDate]
+  /// last selection date will be the same as [lastDate].
+  ///
+  /// If one or more days of week are not selectable according to the
+  /// [selectableDayPredicate] nothing will be returned as selection
+  /// but [UnselectablePeriodException] will be thrown.
+  WeekSelectable(DateTime selectedDate, this._firstDayOfWeekIndex,
+      DateTime firstDate, DateTime lastDate,
+      {SelectableDayPredicate? selectableDayPredicate})
+      : super(firstDate, lastDate,
+            selectableDayPredicate: selectableDayPredicate) {
+    DatePeriod selectedWeek = _getNewSelectedPeriod(selectedDate);
+    _firstDayOfSelectedWeek = selectedWeek.start;
+    _lastDayOfSelectedWeek = selectedWeek.end;
+    _checkCurSelection();
+  }
+
+  @override
+  DayType getDayType(DateTime date) {
+    DayType result;
+
+    DatePeriod selectedPeriod =
+        DatePeriod(_firstDayOfSelectedWeek, _lastDayOfSelectedWeek);
+    bool selectedPeriodIsBroken =
+        _disabledDatesInPeriod(selectedPeriod).isNotEmpty;
+
+    if (isDisabled(date)) {
+      result = DayType.disabled;
+    } else if (_isDaySelected(date) && !selectedPeriodIsBroken) {
+      DateTime firstNotDisabledDayOfSelectedWeek =
+          _firstDayOfSelectedWeek.isBefore(firstDate)
+              ? firstDate
+              : _firstDayOfSelectedWeek;
+
+      DateTime lastNotDisabledDayOfSelectedWeek =
+          _lastDayOfSelectedWeek.isAfter(lastDate)
+              ? lastDate
+              : _lastDayOfSelectedWeek;
+
+      if (DatePickerUtils.sameDate(date, firstNotDisabledDayOfSelectedWeek) &&
+          DatePickerUtils.sameDate(date, lastNotDisabledDayOfSelectedWeek)) {
+        result = DayType.single;
+      } else if (DatePickerUtils.sameDate(date, _firstDayOfSelectedWeek) ||
+          DatePickerUtils.sameDate(date, firstDate)) {
+        result = DayType.start;
+      } else if (DatePickerUtils.sameDate(date, _lastDayOfSelectedWeek) ||
+          DatePickerUtils.sameDate(date, lastDate)) {
+        result = DayType.end;
+      } else {
+        result = DayType.middle;
+      }
+    } else {
+      result = DayType.notSelected;
+    }
+
+    return result;
+  }
+
+  @override
+  void onDayTapped(DateTime selectedDate) {
+    DatePeriod newPeriod = _getNewSelectedPeriod(selectedDate);
+    List<DateTime> customDisabledDays = _disabledDatesInPeriod(newPeriod);
+
+    customDisabledDays.isEmpty
+        ? onUpdateController.add(newPeriod)
+        : onUpdateController.addError(
+            UnselectablePeriodException(customDisabledDays, newPeriod));
+  }
+
+  // Returns new selected period according to tapped date.
+  // Doesn't check custom disabled days.
+  // You have to check it separately if it needs.
+  DatePeriod _getNewSelectedPeriod(DateTime tappedDay) {
+    DatePeriod newPeriod;
+
+    DateTime firstDayOfTappedWeek =
+        DatePickerUtils.getFirstDayOfWeek(tappedDay, _firstDayOfWeekIndex);
+    DateTime lastDayOfTappedWeek =
+        DatePickerUtils.getLastDayOfWeek(tappedDay, _firstDayOfWeekIndex);
+
+    DateTime firstNotDisabledDayOfSelectedWeek =
+        firstDayOfTappedWeek.isBefore(firstDate)
+            ? firstDate
+            : firstDayOfTappedWeek;
+
+    DateTime lastNotDisabledDayOfSelectedWeek =
+        lastDayOfTappedWeek.isAfter(lastDate) ? lastDate : lastDayOfTappedWeek;
+
+    newPeriod = DatePeriod(
+        firstNotDisabledDayOfSelectedWeek, lastNotDisabledDayOfSelectedWeek);
+    return newPeriod;
+  }
+
+  bool _isDaySelected(DateTime date) {
+    DateTime startOfTheStartDay =
+        DatePickerUtils.startOfTheDay(_firstDayOfSelectedWeek);
+    DateTime endOfTheLastDay =
+        DatePickerUtils.endOfTheDay(_lastDayOfSelectedWeek);
+    return !(date.isBefore(startOfTheStartDay) ||
+        date.isAfter(endOfTheLastDay));
+  }
+
+  List<DateTime> _disabledDatesInPeriod(DatePeriod period) {
+    List<DateTime> result = <DateTime>[];
+
+    var date = period.start;
+
+    while (!date.isAfter(period.end)) {
+      if (isDisabled(date)) result.add(date);
+
+      date = date.add(Duration(days: 1));
+    }
+
+    return result;
+  }
+
+  // Returns if current selection contains disabled dates.
+  // Returns false if there is no any selection.
+  bool _checkCurSelection() {
+    bool noSelection =
+        _firstDayOfSelectedWeek == null || _lastDayOfSelectedWeek == null;
+
+    if (noSelection) return false;
+
+    DatePeriod selectedPeriod =
+        DatePeriod(_firstDayOfSelectedWeek, _lastDayOfSelectedWeek);
+    List<DateTime> disabledDates = _disabledDatesInPeriod(selectedPeriod);
+
+    bool selectedPeriodIsBroken = disabledDates.isNotEmpty;
+    return selectedPeriodIsBroken;
+  }
+}
+
+/// Selection logic for [day_picker.DayPicker].
+class DaySelectable extends ISelectablePicker<DateTime> {
+  /// Currently selected date.
+  DateTime selectedDate;
+
+  @override
+  bool get curSelectionIsCorrupted => _checkCurSelection();
+
+  /// Creates selection logic for [day_picker.DayPicker].
+  ///
+  /// Every day can be selected if it is between [firstDate] and [lastDate]
+  /// and not unselectable according to the [selectableDayPredicate].
+  ///
+  /// If day is not selectable according to the [selectableDayPredicate]
+  /// nothing will be returned as selection
+  /// but [UnselectablePeriodException] will be thrown.
+  DaySelectable(this.selectedDate, DateTime firstDate, DateTime lastDate,
+      {SelectableDayPredicate? selectableDayPredicate})
+      : super(firstDate, lastDate,
+            selectableDayPredicate: selectableDayPredicate);
+
+  @override
+  DayType getDayType(DateTime date) {
+    DayType result;
+
+    if (isDisabled(date)) {
+      result = DayType.disabled;
+    } else if (_isDaySelected(date)) {
+      result = DayType.single;
+    } else {
+      result = DayType.notSelected;
+    }
+
+    return result;
+  }
+
+  @override
+  void onDayTapped(DateTime selectedDate) {
+    DateTime newSelected = DatePickerUtils.sameDate(firstDate, selectedDate)
+        ? selectedDate
+        : DateTime(selectedDate.year, selectedDate.month, selectedDate.day);
+    onUpdateController.add(newSelected);
+  }
+
+  bool _isDaySelected(DateTime date) =>
+      DatePickerUtils.sameDate(date, selectedDate);
+
+  // Returns if current selection is disabled
+  // according to the [_selectableDayPredicate].
+  //
+  // Returns false if there is no any selection.
+  bool _checkCurSelection() {
+    if (selectedDate == null) return false;
+    bool selectedIsBroken = _selectableDayPredicate(selectedDate);
+
+    return selectedIsBroken;
+  }
+}
+
+/// Selection logic for [day_picker.DayPicker] where many single days can be
+/// selected.
+class DayMultiSelectable extends ISelectablePicker<List<DateTime>> {
+  /// Currently selected dates.
+  List<DateTime> selectedDates;
+
+  /// Creates selection logic for [day_picker.DayPicker].
+  ///
+  /// Every day can be selected if it is between [firstDate] and [lastDate]
+  /// and not unselectable according to the [selectableDayPredicate].
+  ///
+  /// If day is not selectable according to the [selectableDayPredicate]
+  /// nothing will be returned as selection
+  /// but [UnselectablePeriodException] will be thrown.
+  DayMultiSelectable(this.selectedDates, DateTime firstDate, DateTime lastDate,
+      {SelectableDayPredicate? selectableDayPredicate})
+      : super(firstDate, lastDate,
+            selectableDayPredicate: selectableDayPredicate);
+
+  @override
+  bool get curSelectionIsCorrupted => _checkCurSelection();
+
+  @override
+  DayType getDayType(DateTime date) {
+    DayType result;
+
+    if (isDisabled(date)) {
+      result = DayType.disabled;
+    } else if (_isDaySelected(date)) {
+      result = DayType.single;
+    } else {
+      result = DayType.notSelected;
+    }
+
+    return result;
+  }
+
+  @override
+  void onDayTapped(DateTime selectedDate) {
+    bool alreadyExist =
+        selectedDates.any((d) => DatePickerUtils.sameDate(d, selectedDate));
+
+    if (alreadyExist) {
+      List<DateTime> newSelectedDates = List.from(selectedDates)
+        ..removeWhere((d) => DatePickerUtils.sameDate(d, selectedDate));
+
+      onUpdateController.add(newSelectedDates);
+    } else {
+      DateTime newSelected = DatePickerUtils.sameDate(firstDate, selectedDate)
+          ? selectedDate
+          : DateTime(selectedDate.year, selectedDate.month, selectedDate.day);
+
+      List<DateTime> newSelectedDates = List.from(selectedDates)
+        ..add(newSelected);
+
+      onUpdateController.add(newSelectedDates);
+    }
+  }
+
+  bool _isDaySelected(DateTime date) =>
+      selectedDates.any((d) => DatePickerUtils.sameDate(date, d));
+
+  // Returns if current selection is disabled
+  // according to the [_selectableDayPredicate].
+  //
+  // Returns false if there is no any selection.
+  bool _checkCurSelection() {
+    if (selectedDates == null || selectedDates.isEmpty) return false;
+    bool selectedIsBroken = selectedDates.every(_selectableDayPredicate);
+
+    return selectedIsBroken;
+  }
+}
+
+/// Selection logic for [RangePicker].
+class RangeSelectable extends ISelectablePicker<DatePeriod> {
+  /// Initially selected period.
+  DatePeriod selectedPeriod;
+
+  @override
+  bool get curSelectionIsCorrupted => _checkCurSelection();
+
+  /// Creates selection logic for [RangePicker].
+  ///
+  /// Period can be selected if
+  /// * it is between [firstDate] and [lastDate]
+  /// * it doesn't include unselectable days according to the
+  ///   [selectableDayPredicate]
+  ///
+  ///
+  /// If one or more days of the period are not selectable according to the
+  /// [selectableDayPredicate] nothing will be returned as selection
+  /// but [UnselectablePeriodException] will be thrown.
+  RangeSelectable(this.selectedPeriod, DateTime firstDate, DateTime lastDate,
+      {SelectableDayPredicate? selectableDayPredicate})
+      : super(firstDate, lastDate,
+            selectableDayPredicate: selectableDayPredicate);
+
+  @override
+  DayType getDayType(DateTime date) {
+    DayType result;
+
+    bool selectedPeriodIsBroken =
+        _disabledDatesInPeriod(selectedPeriod).isNotEmpty;
+
+    if (isDisabled(date)) {
+      result = DayType.disabled;
+    } else if (_isDaySelected(date) && !selectedPeriodIsBroken) {
+      if (DatePickerUtils.sameDate(date, selectedPeriod.start) &&
+          DatePickerUtils.sameDate(date, selectedPeriod.end)) {
+        result = DayType.single;
+      } else if (DatePickerUtils.sameDate(date, selectedPeriod.start) ||
+          DatePickerUtils.sameDate(date, firstDate)) {
+        result = DayType.start;
+      } else if (DatePickerUtils.sameDate(date, selectedPeriod.end) ||
+          DatePickerUtils.sameDate(date, lastDate)) {
+        result = DayType.end;
+      } else {
+        result = DayType.middle;
+      }
+    } else {
+      result = DayType.notSelected;
+    }
+
+    return result;
+  }
+
+  @override
+  void onDayTapped(DateTime selectedDate) {
+    DatePeriod newPeriod = _getNewSelectedPeriod(selectedDate);
+    List<DateTime> customDisabledDays = _disabledDatesInPeriod(newPeriod);
+
+    customDisabledDays.isEmpty
+        ? onUpdateController.add(newPeriod)
+        : onUpdateController.addError(
+            UnselectablePeriodException(customDisabledDays, newPeriod));
+  }
+
+  // Returns new selected period according to tapped date.
+  DatePeriod _getNewSelectedPeriod(DateTime tappedDate) {
+    // check if was selected only one date and we should generate period
+    bool sameDate =
+        DatePickerUtils.sameDate(selectedPeriod.start, selectedPeriod.end);
+    DatePeriod newPeriod;
+
+    // Was selected one-day-period.
+    // With new user tap will be generated 2 dates as a period.
+    if (sameDate) {
+      // if user tap on the already selected single day
+      bool selectedAlreadySelectedDay =
+          DatePickerUtils.sameDate(tappedDate, selectedPeriod.end);
+      bool isSelectedFirstDay = DatePickerUtils.sameDate(tappedDate, firstDate);
+      bool isSelectedLastDay = DatePickerUtils.sameDate(tappedDate, lastDate);
+
+      if (selectedAlreadySelectedDay) {
+        if (isSelectedFirstDay && isSelectedLastDay) {
+          newPeriod = DatePeriod(firstDate, lastDate);
+        } else if (isSelectedFirstDay) {
+          newPeriod =
+              DatePeriod(firstDate, DatePickerUtils.endOfTheDay(firstDate));
+        } else if (isSelectedLastDay) {
+          newPeriod =
+              DatePeriod(DatePickerUtils.startOfTheDay(lastDate), lastDate);
+        } else {
+          newPeriod = DatePeriod(DatePickerUtils.startOfTheDay(tappedDate),
+              DatePickerUtils.endOfTheDay(tappedDate));
+        }
+      } else {
+        DateTime startOfTheSelectedDay =
+            DatePickerUtils.startOfTheDay(selectedPeriod.start);
+
+        if (!tappedDate.isAfter(startOfTheSelectedDay)) {
+          newPeriod = DatePickerUtils.sameDate(tappedDate, firstDate)
+              ? DatePeriod(firstDate, selectedPeriod.end)
+              : DatePeriod(DatePickerUtils.startOfTheDay(tappedDate),
+                  selectedPeriod.end);
+        } else {
+          newPeriod = DatePickerUtils.sameDate(tappedDate, lastDate)
+              ? DatePeriod(selectedPeriod.start, lastDate)
+              : DatePeriod(selectedPeriod.start,
+                  DatePickerUtils.endOfTheDay(tappedDate));
+        }
+      }
+
+      // Was selected 2 dates as a period.
+      // With new user tap new one-day-period will be generated.
+    } else {
+      bool sameAsFirst = DatePickerUtils.sameDate(tappedDate, firstDate);
+      bool sameAsLast = DatePickerUtils.sameDate(tappedDate, lastDate);
+
+      if (sameAsFirst && sameAsLast) {
+        newPeriod = DatePeriod(firstDate, lastDate);
+      } else if (sameAsFirst) {
+        newPeriod =
+            DatePeriod(firstDate, DatePickerUtils.endOfTheDay(firstDate));
+      } else if (sameAsLast) {
+        newPeriod =
+            DatePeriod(DatePickerUtils.startOfTheDay(tappedDate), lastDate);
+      } else {
+        newPeriod = DatePeriod(DatePickerUtils.startOfTheDay(tappedDate),
+            DatePickerUtils.endOfTheDay(tappedDate));
+      }
+    }
+
+    return newPeriod;
+  }
+
+  // Returns if current selection contains disabled dates.
+  // Returns false if there is no any selection.
+  bool _checkCurSelection() {
+    if (selectedPeriod == null) return false;
+    List<DateTime> disabledDates = _disabledDatesInPeriod(selectedPeriod);
+
+    bool selectedPeriodIsBroken = disabledDates.isNotEmpty;
+    return selectedPeriodIsBroken;
+  }
+
+  List<DateTime> _disabledDatesInPeriod(DatePeriod period) {
+    List<DateTime> result = <DateTime>[];
+
+    var date = period.start;
+
+    while (!date.isAfter(period.end)) {
+      if (isDisabled(date)) result.add(date);
+
+      date = date.add(Duration(days: 1));
+    }
+
+    return result;
+  }
+
+  bool _isDaySelected(DateTime date) {
+    DateTime startOfTheStartDay =
+        DatePickerUtils.startOfTheDay(selectedPeriod.start);
+    DateTime endOfTheLastDay = DatePickerUtils.endOfTheDay(selectedPeriod.end);
+    return !(date.isBefore(startOfTheStartDay) ||
+        date.isAfter(endOfTheLastDay));
+  }
+}

flutter_date_pickers-master/lib/src/icon_btn.dart

@@ -0,0 +1,54 @@
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+
+/// Icon button widget built different
+/// depends on [MaterialApp] or [CupertinoApp] ancestor.
+class IconBtn extends StatelessWidget {
+  /// Widget to use inside button.
+  ///
+  /// Typically [Icon] widget.
+  final Widget icon;
+
+  /// Function called when user tap on the button.
+  ///
+  /// Can be null. In this case button will be disabled.
+  final VoidCallback? onTap;
+
+  /// Tooltip for button.
+  ///
+  /// Applied only for material style buttons.
+  /// It means only if widget has [MaterialApp] ancestor.
+  final String? tooltip;
+
+  /// Creates button with [icon] different
+  /// depends on [MaterialApp] or [CupertinoApp] ancestor.
+  const IconBtn({
+    Key? key,
+    required this.icon,
+    this.onTap,
+    this.tooltip
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    bool isMaterial =  Material.of(context) != null;
+
+    return isMaterial
+      ? _materialBtn()
+      : _cupertinoBtn();
+  }
+
+  Widget _cupertinoBtn() =>
+      CupertinoButton(
+        padding: const EdgeInsets.all(0.0),
+        child: icon,
+        onPressed: onTap,
+      );
+
+  Widget _materialBtn() =>
+     IconButton(
+       icon: icon,
+       tooltip: tooltip ?? "",
+       onPressed: onTap,
+    );
+}

flutter_date_pickers-master/lib/src/layout_settings.dart

@@ -0,0 +1,115 @@
+import 'dart:math' as math;
+
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'day_picker.dart';
+import 'month_picker.dart';
+import 'range_picker.dart';
+import 'week_picker.dart';
+
+// layout defaults
+const Duration _kPageScrollDuration = Duration(milliseconds: 200);
+const double _kDayPickerRowHeight = 42.0;
+const int _kMaxDayPickerRowCount = 6; // A 31 day month that starts on Saturday.
+const double _kMonthPickerPortraitWidth = 330.0;
+const EdgeInsetsGeometry _kContentPadding =
+    EdgeInsets.symmetric(horizontal: 8.0);
+
+/// Settings for the layout of the [DayPicker], [WeekPicker], [RangePicker]
+/// and [MonthPicker].
+class DatePickerLayoutSettings {
+  /// Duration for scroll to previous or next page.
+  final Duration pagesScrollDuration;
+
+  /// Determines the scroll physics of a date picker widget.
+  ///
+  /// Can be null. In this case default physics for [ScrollView] will be used.
+  final ScrollPhysics? scrollPhysics;
+
+  /// Height of the one row in picker including headers.
+  ///
+  /// Default is [_kDayPickerRowHeight].
+  final double dayPickerRowHeight;
+
+  /// Width of the day based pickers.
+  final double monthPickerPortraitWidth;
+
+  ///
+  final int maxDayPickerRowCount;
+
+  /// Padding for the entire picker.
+  final EdgeInsetsGeometry contentPadding;
+
+  /// If the first dates from the next month should be shown
+  /// to complete last week of the selected month.
+  ///
+  /// false by default.
+  final bool showNextMonthStart;
+
+  /// If the last dates from the previous month should be shown
+  /// to complete first week of the selected month.
+  ///
+  /// false by default.
+  final bool showPrevMonthEnd;
+    
+  /// Hide Month navigation row
+  /// false by default.
+  final bool hideMonthNavigationRow;
+
+  /// Grid delegate for the picker according to [dayPickerRowHeight] and
+  /// [maxDayPickerRowCount].
+  SliverGridDelegate get dayPickerGridDelegate =>
+      _DayPickerGridDelegate(dayPickerRowHeight, maxDayPickerRowCount);
+
+  /// Maximum height of the day based picker according to [dayPickerRowHeight]
+  /// and [maxDayPickerRowCount].
+  ///
+  /// Two extra rows:
+  /// one for the day-of-week header and one for the month header.
+  double get maxDayPickerHeight =>
+      dayPickerRowHeight * (maxDayPickerRowCount + 2);
+
+  /// Creates layout settings for the date picker.
+  ///
+  /// Usually used in [DayPicker], [WeekPicker], [RangePicker]
+  /// and [MonthPicker].
+  const DatePickerLayoutSettings({
+    this.pagesScrollDuration = _kPageScrollDuration,
+    this.dayPickerRowHeight = _kDayPickerRowHeight,
+    this.monthPickerPortraitWidth = _kMonthPickerPortraitWidth,
+    this.maxDayPickerRowCount = _kMaxDayPickerRowCount,
+    this.contentPadding = _kContentPadding,
+    this.showNextMonthStart = false,
+    this.showPrevMonthEnd = false,
+    this.hideMonthNavigationRow = false,
+    this.scrollPhysics
+  });
+}
+
+
+class _DayPickerGridDelegate extends SliverGridDelegate {
+  final double _dayPickerRowHeight;
+  final int _maxDayPickerRowCount;
+
+  const _DayPickerGridDelegate(
+      this._dayPickerRowHeight, this._maxDayPickerRowCount);
+
+  @override
+  SliverGridLayout getLayout(SliverConstraints constraints) {
+    const int columnCount = DateTime.daysPerWeek;
+    final double tileWidth = constraints.crossAxisExtent / columnCount;
+    final double tileHeight = math.min(_dayPickerRowHeight,
+        constraints.viewportMainAxisExtent / (_maxDayPickerRowCount + 1));
+    return SliverGridRegularTileLayout(
+      crossAxisCount: columnCount,
+      mainAxisStride: tileHeight,
+      crossAxisStride: tileWidth,
+      childMainAxisExtent: tileHeight,
+      childCrossAxisExtent: tileWidth,
+      reverseCrossAxis: axisDirectionIsReversed(constraints.crossAxisDirection),
+    );
+  }
+
+  @override
+  bool shouldRelayout(SliverGridDelegate oldDelegate) => false;
+}

flutter_date_pickers-master/lib/src/month_navigation_row.dart

@@ -0,0 +1,99 @@
+import 'package:flutter/material.dart';
+import 'day_picker.dart' as day_picker;
+import 'icon_btn.dart';
+import 'range_picker.dart';
+import 'semantic_sorting.dart';
+import 'week_picker.dart';
+
+/// Month navigation widget for day based date pickers like
+/// [day_picker.DayPicker],
+/// [WeekPicker],
+/// [RangePicker].
+///
+/// It is row with [title] of showing month in the center and icons to selects
+/// previous and next month around it.
+class MonthNavigationRow extends StatelessWidget {
+  /// Key for previous page icon.
+  ///
+  /// Can be useful in integration tests to find icon.
+  final Key? previousPageIconKey;
+
+  /// Key for next page icon.
+  ///
+  /// Can be useful in integration tests to find icon.
+  final Key? nextPageIconKey;
+
+  /// Function called when [nextIcon] is tapped.
+  final VoidCallback? onNextMonthTapped;
+
+  /// Function called when [prevIcon] is tapped.
+  final VoidCallback? onPreviousMonthTapped;
+
+  /// Tooltip for the [nextIcon].
+  final String? nextMonthTooltip;
+
+  /// Tooltip for the [prevIcon].
+  final String? previousMonthTooltip;
+
+  /// Widget to use at the end of this row (after title).
+  final Widget nextIcon;
+
+  /// Widget to use at the beginning of this row (before title).
+  final Widget prevIcon;
+
+  /// Usually [Text] widget.
+  final Widget? title;
+
+  /// Creates month navigation row.
+  const MonthNavigationRow({
+    Key? key,
+    this.previousPageIconKey,
+    this.nextPageIconKey,
+    this.onNextMonthTapped,
+    this.onPreviousMonthTapped,
+    this.nextMonthTooltip,
+    this.previousMonthTooltip,
+    this.title,
+    required this.nextIcon,
+    required this.prevIcon
+  }) : super(key: key);
+
+  @override
+  // ignore: prefer_expression_function_bodies
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+      crossAxisAlignment: CrossAxisAlignment.center,
+      children: <Widget>[
+        Semantics(
+          sortKey: MonthPickerSortKey.previousMonth,
+          child: IconBtn(
+            key: previousPageIconKey,
+            icon: prevIcon,
+            tooltip: previousMonthTooltip,
+            onTap: onPreviousMonthTapped,
+          ),
+        ),
+        Expanded(
+          child: Container(
+            alignment: Alignment.center,
+            child: Center(
+              child: ExcludeSemantics(
+                child: title,
+              ),
+            ),
+          ),
+        ),
+        Semantics(
+          sortKey: MonthPickerSortKey.nextMonth,
+          child: IconBtn(
+            key: nextPageIconKey,
+            icon: nextIcon,
+            tooltip: nextMonthTooltip,
+            onTap: onNextMonthTapped,
+          ),
+        ),
+      ],
+    );
+  }
+}

flutter_date_pickers-master/lib/src/month_picker.dart

@@ -0,0 +1,440 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:intl/intl.dart' as intl;
+
+import 'date_picker_keys.dart';
+import 'date_picker_styles.dart';
+import 'layout_settings.dart';
+import 'semantic_sorting.dart';
+import 'utils.dart';
+
+const Locale _defaultLocale = Locale('en', 'US');
+
+/// Month picker widget.
+class MonthPicker extends StatefulWidget {
+  /// Month picker widget.
+  MonthPicker(
+      {Key? key,
+      required this.selectedDate,
+      required this.onChanged,
+      required this.firstDate,
+      required this.lastDate,
+      this.datePickerLayoutSettings = const DatePickerLayoutSettings(),
+      this.datePickerKeys,
+      required this.datePickerStyles})
+      : assert(!firstDate.isAfter(lastDate)),
+        assert(!selectedDate.isBefore(firstDate)),
+        assert(!selectedDate.isAfter(lastDate)),
+        super(key: key);
+
+  /// The currently selected date.
+  ///
+  /// This date is highlighted in the picker.
+  final DateTime selectedDate;
+
+  /// Called when the user picks a month.
+  final ValueChanged<DateTime> onChanged;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Some keys useful for integration tests
+  final DatePickerKeys? datePickerKeys;
+
+  /// Styles what can be customized by user
+  final DatePickerStyles datePickerStyles;
+
+  @override
+  State<StatefulWidget> createState() => _MonthPickerState();
+}
+
+class _MonthPickerState extends State<MonthPicker> {
+  PageController _monthPickerController = PageController();
+
+  Locale locale = _defaultLocale;
+  MaterialLocalizations localizations = _defaultLocalizations;
+
+  TextDirection textDirection = TextDirection.ltr;
+
+  DateTime _todayDate = DateTime.now();
+  DateTime _previousYearDate = DateTime(DateTime.now().year - 1);
+  DateTime _nextYearDate = DateTime(DateTime.now().year + 1);
+
+  DateTime _currentDisplayedYearDate = DateTime.now();
+
+  Timer? _timer;
+
+  /// True if the earliest allowable year is displayed.
+  bool get _isDisplayingFirstYear =>
+      !_currentDisplayedYearDate.isAfter(DateTime(widget.firstDate.year));
+
+  /// True if the latest allowable year is displayed.
+  bool get _isDisplayingLastYear =>
+      !_currentDisplayedYearDate.isBefore(DateTime(widget.lastDate.year));
+
+  @override
+  void initState() {
+    super.initState();
+    // Initially display the pre-selected date.
+    final int yearPage =
+        DatePickerUtils.yearDelta(widget.firstDate, widget.selectedDate);
+
+    _monthPickerController.dispose();
+    _monthPickerController = PageController(initialPage: yearPage);
+    _handleYearPageChanged(yearPage);
+    _updateCurrentDate();
+  }
+
+  @override
+  void didUpdateWidget(MonthPicker oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.selectedDate != oldWidget.selectedDate) {
+      final int yearPage =
+          DatePickerUtils.yearDelta(widget.firstDate, widget.selectedDate);
+      _monthPickerController = PageController(initialPage: yearPage);
+      _handleYearPageChanged(yearPage);
+    }
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+
+    try {
+      locale = Localizations.localeOf(context);
+
+      MaterialLocalizations? curLocalizations =
+          Localizations.of<MaterialLocalizations>(
+              context, MaterialLocalizations);
+      if (curLocalizations != null && localizations != curLocalizations) {
+        localizations = curLocalizations;
+      }
+
+      textDirection = Directionality.of(context);
+
+      // No MaterialLocalizations or Directionality or Locale was found
+      // and ".of" method throws error
+      // trying to cast null to MaterialLocalizations.
+    } on TypeError catch (_) {}
+  }
+
+  void _updateCurrentDate() {
+    _todayDate = DateTime.now();
+    final DateTime tomorrow =
+        DateTime(_todayDate.year, _todayDate.month, _todayDate.day + 1);
+    Duration timeUntilTomorrow = tomorrow.difference(_todayDate);
+    timeUntilTomorrow +=
+        const Duration(seconds: 1); // so we don't miss it by rounding
+    _timer?.cancel();
+    _timer = Timer(timeUntilTomorrow, () {
+      setState(_updateCurrentDate);
+    });
+  }
+
+  /// Add years to a year truncated date.
+  DateTime _addYearsToYearDate(DateTime yearDate, int yearsToAdd) =>
+      DateTime(yearDate.year + yearsToAdd);
+
+  Widget _buildItems(BuildContext context, int index) {
+    final DateTime year = _addYearsToYearDate(widget.firstDate, index);
+
+    final ThemeData theme = Theme.of(context);
+    DatePickerStyles styles = widget.datePickerStyles;
+    styles = styles.fulfillWithTheme(theme);
+
+    return _MonthPicker(
+      key: ValueKey<DateTime>(year),
+      selectedDate: widget.selectedDate,
+      currentDate: _todayDate,
+      onChanged: widget.onChanged,
+      firstDate: widget.firstDate,
+      lastDate: widget.lastDate,
+      datePickerLayoutSettings: widget.datePickerLayoutSettings,
+      displayedYear: year,
+      selectedPeriodKey: widget.datePickerKeys?.selectedPeriodKeys,
+      datePickerStyles: styles,
+      locale: locale,
+      localizations: localizations,
+    );
+  }
+
+  void _handleNextYear() {
+    if (!_isDisplayingLastYear) {
+      String yearStr = localizations.formatYear(_nextYearDate);
+      SemanticsService.announce(yearStr, textDirection);
+      _monthPickerController.nextPage(
+          duration: widget.datePickerLayoutSettings.pagesScrollDuration,
+          curve: Curves.ease);
+    }
+  }
+
+  void _handlePreviousYear() {
+    if (!_isDisplayingFirstYear) {
+      String yearStr = localizations.formatYear(_previousYearDate);
+      SemanticsService.announce(yearStr, textDirection);
+      _monthPickerController.previousPage(
+          duration: widget.datePickerLayoutSettings.pagesScrollDuration,
+          curve: Curves.ease);
+    }
+  }
+
+  void _handleYearPageChanged(int yearPage) {
+    setState(() {
+      _previousYearDate = _addYearsToYearDate(widget.firstDate, yearPage - 1);
+      _currentDisplayedYearDate =
+          _addYearsToYearDate(widget.firstDate, yearPage);
+      _nextYearDate = _addYearsToYearDate(widget.firstDate, yearPage + 1);
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    int yearsCount =
+        DatePickerUtils.yearDelta(widget.firstDate, widget.lastDate) + 1;
+
+    return SizedBox(
+      width: widget.datePickerLayoutSettings.monthPickerPortraitWidth,
+      height: widget.datePickerLayoutSettings.maxDayPickerHeight,
+      child: Stack(
+        children: <Widget>[
+          Semantics(
+            sortKey: YearPickerSortKey.calendar,
+            child: PageView.builder(
+              key: ValueKey<DateTime>(widget.selectedDate),
+              controller: _monthPickerController,
+              scrollDirection: Axis.horizontal,
+              itemCount: yearsCount,
+              itemBuilder: _buildItems,
+              onPageChanged: _handleYearPageChanged,
+            ),
+          ),
+          PositionedDirectional(
+            top: 0.0,
+            start: 8.0,
+            child: Semantics(
+              sortKey: YearPickerSortKey.previousYear,
+              child: IconButton(
+                key: widget.datePickerKeys?.previousPageIconKey,
+                icon: widget.datePickerStyles.prevIcon,
+                tooltip: _isDisplayingFirstYear
+                    ? null
+                    : '${localizations.formatYear(_previousYearDate)}',
+                onPressed: _isDisplayingFirstYear ? null : _handlePreviousYear,
+              ),
+            ),
+          ),
+          PositionedDirectional(
+            top: 0.0,
+            end: 8.0,
+            child: Semantics(
+              sortKey: YearPickerSortKey.nextYear,
+              child: IconButton(
+                key: widget.datePickerKeys?.nextPageIconKey,
+                icon: widget.datePickerStyles.nextIcon,
+                tooltip: _isDisplayingLastYear
+                    ? null
+                    : '${localizations.formatYear(_nextYearDate)}',
+                onPressed: _isDisplayingLastYear ? null : _handleNextYear,
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  static MaterialLocalizations get _defaultLocalizations =>
+      MaterialLocalizationEn(
+        twoDigitZeroPaddedFormat:
+            intl.NumberFormat('00', _defaultLocale.toString()),
+        fullYearFormat: intl.DateFormat.y(_defaultLocale.toString()),
+        longDateFormat: intl.DateFormat.yMMMMEEEEd(_defaultLocale.toString()),
+        shortMonthDayFormat: intl.DateFormat.MMMd(_defaultLocale.toString()),
+        decimalFormat:
+            intl.NumberFormat.decimalPattern(_defaultLocale.toString()),
+        shortDateFormat: intl.DateFormat.yMMMd(_defaultLocale.toString()),
+        mediumDateFormat: intl.DateFormat.MMMEd(_defaultLocale.toString()),
+        compactDateFormat: intl.DateFormat.yMd(_defaultLocale.toString()),
+        yearMonthFormat: intl.DateFormat.yMMMM(_defaultLocale.toString()),
+      );
+}
+
+class _MonthPicker extends StatelessWidget {
+  /// The month whose days are displayed by this picker.
+  final DateTime displayedYear;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// The currently selected date.
+  ///
+  /// This date is highlighted in the picker.
+  final DateTime selectedDate;
+
+  /// The current date at the time the picker is displayed.
+  final DateTime currentDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Called when the user picks a day.
+  final ValueChanged<DateTime> onChanged;
+
+  ///  Key fo selected month (useful for integration tests)
+  final Key? selectedPeriodKey;
+
+  /// Styles what can be customized by user
+  final DatePickerStyles datePickerStyles;
+
+  final MaterialLocalizations localizations;
+
+  final Locale locale;
+
+  _MonthPicker(
+      {required this.displayedYear,
+      required this.firstDate,
+      required this.lastDate,
+      required this.selectedDate,
+      required this.currentDate,
+      required this.onChanged,
+      required this.datePickerLayoutSettings,
+      required this.datePickerStyles,
+      required this.localizations,
+      required this.locale,
+      this.selectedPeriodKey,
+      Key? key})
+      : assert(!firstDate.isAfter(lastDate)),
+        assert(selectedDate.isAfter(firstDate) ||
+            selectedDate.isAtSameMomentAs(firstDate)),
+        super(key: key);
+
+  // We only need to know if month of passed day
+  // before the month of the firstDate or after the month of the lastDate.
+  //
+  // Don't need to compare day and time.
+  bool _isDisabled(DateTime month) {
+    DateTime beginningOfTheFirstDateMonth =
+        DateTime(firstDate.year, firstDate.month);
+    DateTime endOfTheLastDateMonth = DateTime(lastDate.year, lastDate.month + 1)
+        .subtract(Duration(microseconds: 1));
+
+    return month.isAfter(endOfTheLastDateMonth) ||
+        month.isBefore(beginningOfTheFirstDateMonth);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final ThemeData themeData = Theme.of(context);
+    final int monthsInYear = 12;
+    final int year = displayedYear.year;
+    final int day = 1;
+
+    final List<Widget> labels = <Widget>[];
+
+    for (int i = 0; i < monthsInYear; i += 1) {
+      final int month = i + 1;
+      final DateTime monthToBuild = DateTime(year, month, day);
+
+      final bool disabled = _isDisabled(monthToBuild);
+      final bool isSelectedMonth =
+          selectedDate.year == year && selectedDate.month == month;
+
+      BoxDecoration? decoration;
+      TextStyle? itemStyle = themeData.textTheme.bodyText2;
+
+      if (isSelectedMonth) {
+        itemStyle = datePickerStyles.selectedDateStyle;
+        decoration = datePickerStyles.selectedSingleDateDecoration;
+      } else if (disabled) {
+        itemStyle = datePickerStyles.disabledDateStyle;
+      } else if (currentDate.year == year && currentDate.month == month) {
+        // The current month gets a different text color.
+        itemStyle = datePickerStyles.currentDateStyle;
+      } else {
+        itemStyle = datePickerStyles.defaultDateTextStyle;
+      }
+
+      String monthStr = _getMonthStr(monthToBuild);
+
+      Widget monthWidget = Container(
+        decoration: decoration,
+        child: Center(
+          child: Semantics(
+            // We want the day of month to be spoken first irrespective of the
+            // locale-specific preferences or TextDirection. This is because
+            // an accessibility user is more likely to be interested in the
+            // day of month before the rest of the date, as they are looking
+            // for the day of month. To do that we prepend day of month to the
+            // formatted full date.
+            label: '${localizations.formatDecimal(month)}, '
+                '${localizations.formatFullDate(monthToBuild)}',
+            selected: isSelectedMonth,
+            child: ExcludeSemantics(
+              child: Text(monthStr, style: itemStyle),
+            ),
+          ),
+        ),
+      );
+
+      if (!disabled) {
+        monthWidget = GestureDetector(
+          behavior: HitTestBehavior.opaque,
+          onTap: () {
+            DatePickerUtils.sameMonth(firstDate, monthToBuild)
+                ? onChanged(firstDate)
+                : onChanged(monthToBuild);
+          },
+          child: monthWidget,
+        );
+      }
+      labels.add(monthWidget);
+    }
+
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 8.0),
+      child: Column(
+        children: <Widget>[
+          Container(
+            height: datePickerLayoutSettings.dayPickerRowHeight,
+            child: Center(
+              child: ExcludeSemantics(
+                child: Text(
+                  localizations.formatYear(displayedYear),
+                  key: selectedPeriodKey,
+                  style: datePickerStyles.displayedPeriodTitle,
+                ),
+              ),
+            ),
+          ),
+          Flexible(
+            child: GridView.count(
+              physics: datePickerLayoutSettings.scrollPhysics,
+              crossAxisCount: 4,
+              children: labels,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  // Returns only month made with intl.DateFormat.MMM() for current [locale].
+  // We can'r use [localizations] here because MaterialLocalizations doesn't
+  // provide short month string.
+  String _getMonthStr(DateTime date) {
+    String month = intl.DateFormat.MMM(locale.toString()).format(date);
+    return month;
+  }
+}

flutter_date_pickers-master/lib/src/range_picker.dart

@@ -0,0 +1,109 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+
+import 'date_period.dart';
+import 'date_picker_keys.dart';
+import 'date_picker_styles.dart';
+import 'day_based_changable_picker.dart';
+import 'day_picker_selection.dart';
+import 'day_type.dart';
+import 'event_decoration.dart';
+import 'i_selectable_picker.dart';
+import 'layout_settings.dart';
+import 'typedefs.dart';
+
+/// Date picker for range selection.
+class RangePicker extends StatelessWidget {
+  /// Creates a range picker.
+  RangePicker(
+      {Key? key,
+      required this.selectedPeriod,
+      required this.onChanged,
+      required this.firstDate,
+      required this.lastDate,
+      this.initiallyShowDate,
+      this.datePickerLayoutSettings = const DatePickerLayoutSettings(),
+      this.datePickerStyles,
+      this.datePickerKeys,
+      this.selectableDayPredicate,
+      this.onSelectionError,
+      this.eventDecorationBuilder,
+      this.onMonthChanged})
+      : assert(!firstDate.isAfter(lastDate)),
+        assert(!lastDate.isBefore(firstDate)),
+        assert(!selectedPeriod.start.isBefore(firstDate)),
+        assert(!selectedPeriod.end.isAfter(lastDate)),
+        assert(initiallyShowDate == null
+            || !initiallyShowDate.isAfter(lastDate)),
+        assert(initiallyShowDate == null
+            || !initiallyShowDate.isBefore(firstDate)),
+        super(key: key);
+
+  /// The currently selected period.
+  ///
+  /// This date is highlighted in the picker.
+  final DatePeriod selectedPeriod;
+
+  /// Called when the user picks a week.
+  final ValueChanged<DatePeriod> onChanged;
+
+  /// Called when the error was thrown after user selection.
+  /// (e.g. when user selected a range with one or more days
+  /// that can't be selected)
+  final OnSelectionError? onSelectionError;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// Date for defining what month should be shown initially.
+  ///
+  /// In case of null start of the [selectedPeriod] will be shown.
+  final DateTime? initiallyShowDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Some keys useful for integration tests
+  final DatePickerKeys? datePickerKeys;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles? datePickerStyles;
+
+  /// Function returns if day can be selected or not.
+  final SelectableDayPredicate? selectableDayPredicate;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overridden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  /// Called when the user changes the month.
+  /// New DateTime object represents first day of new month and 00:00 time.
+  final ValueChanged<DateTime>? onMonthChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    ISelectablePicker<DatePeriod> rangeSelectablePicker = RangeSelectable(
+        selectedPeriod, firstDate, lastDate,
+        selectableDayPredicate: selectableDayPredicate);
+
+    return DayBasedChangeablePicker<DatePeriod>(
+      selectablePicker: rangeSelectablePicker,
+      selection: DayPickerRangeSelection(selectedPeriod),
+      firstDate: firstDate,
+      lastDate: lastDate,
+      initiallyShownDate: initiallyShowDate,
+      onChanged: onChanged,
+      onSelectionError: onSelectionError,
+      datePickerLayoutSettings: datePickerLayoutSettings,
+      datePickerStyles: datePickerStyles ?? DatePickerRangeStyles(),
+      datePickerKeys: datePickerKeys,
+      eventDecorationBuilder: eventDecorationBuilder,
+      onMonthChanged: onMonthChanged,
+    );
+  }
+}

flutter_date_pickers-master/lib/src/semantic_sorting.dart

@@ -0,0 +1,33 @@
+import 'package:flutter/semantics.dart';
+
+/// Defines semantic traversal order of the top-level widgets
+/// inside the day or week picker.
+class MonthPickerSortKey extends OrdinalSortKey {
+  /// Previous month key.
+  static const MonthPickerSortKey previousMonth = MonthPickerSortKey(1.0);
+
+  /// Next month key.
+  static const MonthPickerSortKey nextMonth = MonthPickerSortKey(2.0);
+
+  /// Calendar key.
+  static const MonthPickerSortKey calendar = MonthPickerSortKey(3.0);
+
+  ///
+  const MonthPickerSortKey(double order) : super(order);
+}
+
+/// Defines semantic traversal order of the top-level widgets
+/// inside the month picker.
+class YearPickerSortKey extends OrdinalSortKey {
+  /// Previous year key.
+  static const YearPickerSortKey previousYear = YearPickerSortKey(1.0);
+
+  /// Next year key.
+  static const YearPickerSortKey nextYear = YearPickerSortKey(2.0);
+
+  /// Calendar key.
+  static const YearPickerSortKey calendar = YearPickerSortKey(3.0);
+
+  ///
+  const YearPickerSortKey(double order) : super(order);
+}

flutter_date_pickers-master/lib/src/typedefs.dart

@@ -0,0 +1,11 @@
+import 'range_picker.dart';
+import 'unselectable_period_error.dart';
+import 'week_picker.dart';
+
+
+/// Signature for function that can be used to handle incorrect selections.
+///
+/// See also:
+/// * [WeekPicker.onSelectionError]
+/// * [RangePicker.onSelectionError]
+typedef OnSelectionError = void Function(UnselectablePeriodException e);

flutter_date_pickers-master/lib/src/unselectable_period_error.dart

@@ -0,0 +1,30 @@
+import 'date_period.dart';
+import 'range_picker.dart';
+import 'week_picker.dart';
+
+
+/// Exception thrown when selected period contains custom disabled days.
+class UnselectablePeriodException implements Exception {
+  /// Dates inside selected period what can't be selected
+  /// according custom rules.
+  final List<DateTime> customDisabledDates;
+
+  /// Selected period wanted by the user.
+  final DatePeriod period;
+
+  /// Creates exception that stores dates that can not be selected.
+  ///
+  /// See also:
+  /// *[WeekPicker.onSelectionError]
+  /// *[RangePicker.onSelectionError]
+  UnselectablePeriodException(this.customDisabledDates, this.period);
+
+  @override
+  String toString() =>
+        "UnselectablePeriodException:"
+        " ${customDisabledDates.length} dates inside selected period "
+        "(${period.start} - ${period.end}) "
+        "can't be selected according custom rules (selectable pridicate). "
+        "Check 'customDisabledDates' property "
+        "to get entire list of such dates.";
+}

flutter_date_pickers-master/lib/src/utils.dart

@@ -0,0 +1,251 @@
+/// Bunch of useful functions for date pickers.
+class DatePickerUtils {
+  /// Returns if two objects have same year, month and day.
+  /// Time doesn't matter.
+  static bool sameDate(DateTime dateTimeOne, DateTime dateTimeTwo) =>
+     dateTimeOne.year == dateTimeTwo.year &&
+     dateTimeOne.month == dateTimeTwo.month &&
+     dateTimeOne.day == dateTimeTwo.day;
+
+  /// Returns if two objects have same year and month.
+  /// Day and time don't matter/
+  static bool sameMonth(DateTime dateTimeOne, DateTime dateTimeTwo) =>
+      dateTimeOne.year == dateTimeTwo.year
+      && dateTimeOne.month == dateTimeTwo.month;
+
+
+  // Do not use this directly - call getDaysInMonth instead.
+  static const List<int> _daysInMonth = <int>[
+    31,
+    -1,
+    31,
+    30,
+    31,
+    30,
+    31,
+    31,
+    30,
+    31,
+    30,
+    31
+  ];
+
+
+  /// Returns the number of days in a month, according to the proleptic
+  /// Gregorian calendar.
+  ///
+  /// This applies the leap year logic introduced by the Gregorian reforms of
+  /// 1582. It will not give valid results for dates prior to that time.
+  static int getDaysInMonth(int year, int month) {
+    if (month == DateTime.february) {
+      final bool isLeapYear =
+          (year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0);
+      return isLeapYear ? 29 : 28;
+    }
+    return _daysInMonth[month - 1];
+  }
+
+
+  /// Returns number of months between [startDate] and [endDate]
+  static int monthDelta(DateTime startDate, DateTime endDate) =>
+     (endDate.year - startDate.year) * 12 +
+        endDate.month -
+        startDate.month;
+
+
+  /// Add months to a month truncated date.
+  static DateTime addMonthsToMonthDate(DateTime monthDate, int monthsToAdd) =>
+    // year is switched automatically if new month > 12
+    DateTime(monthDate.year, monthDate.month + monthsToAdd);
+
+
+  /// Returns number of years between [startDate] and [endDate]
+  static int yearDelta(DateTime startDate, DateTime endDate) =>
+     endDate.year - startDate.year;
+
+
+  /// Returns start of the first day of the week with given day.
+  ///
+  /// Start of the week calculated using firstDayIndex which is int from 0 to 6
+  /// where 0 points to Sunday and 6 points to Saturday.
+  /// (according to MaterialLocalization.firstDayIfWeekIndex)
+  static DateTime getFirstDayOfWeek(DateTime day, int firstDayIndex) {
+    // from 1 to 7 where 1 points to Monday and 7 points to Sunday
+    int weekday = day.weekday;
+
+    // to match weekdays where Sunday is 7 not 0
+    if (firstDayIndex == 0) firstDayIndex = 7;
+
+    int diff = weekday - firstDayIndex;
+    if (diff < 0) diff = 7 + diff;
+
+    DateTime firstDayOfWeek = day.subtract(Duration(days: diff));
+    firstDayOfWeek = startOfTheDay(firstDayOfWeek);
+    return firstDayOfWeek;
+  }
+
+  /// Returns end of the last day of the week with given day.
+  ///
+  /// Start of the week calculated using firstDayIndex which is int from 0 to 6
+  /// where 0 points to Sunday and 6 points to Saturday.
+  /// (according to MaterialLocalization.firstDayIfWeekIndex)
+  static DateTime getLastDayOfWeek(DateTime day, int firstDayIndex) {
+    // from 1 to 7 where 1 points to Monday and 7 points to Sunday
+    int weekday = day.weekday;
+
+    // to match weekdays where Sunday is 7 not 0
+    if (firstDayIndex == 0) firstDayIndex = 7;
+
+    int lastDayIndex = firstDayIndex - 1;
+    if (lastDayIndex == 0) lastDayIndex = 7;
+
+    int diff = lastDayIndex - weekday;
+    if (diff < 0) diff = 7 + diff;
+
+    DateTime lastDayOfWeek = day.add(Duration(days: diff));
+    lastDayOfWeek = endOfTheDay(lastDayOfWeek);
+    return lastDayOfWeek;
+  }
+
+  /// Returns end of the given day.
+  ///
+  /// End time is 1 millisecond before start of the next day.
+  static DateTime endOfTheDay(DateTime date) {
+    DateTime tomorrowStart = DateTime(date.year, date.month, date.day + 1);
+    DateTime result = tomorrowStart.subtract(const Duration(milliseconds: 1));
+
+    return result;
+  }
+
+
+  /// Returns start of the given day.
+  ///
+  /// Start time is 00:00:00.
+  static DateTime startOfTheDay(DateTime date) =>
+     DateTime(date.year, date.month, date.day);
+
+  /// Returns first shown date for the [curMonth].
+  ///
+  /// First shown date is not always 1st day of the [curMonth].
+  /// It can be day from previous month if [showEndOfPrevMonth] is true.
+  ///
+  /// If [showEndOfPrevMonth] is true empty day cells before 1st [curMonth]
+  /// are filled with days from the previous month.
+  static DateTime firstShownDate({
+      required DateTime curMonth,
+      required bool showEndOfPrevMonth,
+      required int firstDayOfWeekFromSunday}) {
+
+    DateTime result = DateTime(curMonth.year, curMonth.month, 1);
+
+    if (showEndOfPrevMonth) {
+      int firstDayOffset = computeFirstDayOffset(curMonth.year, curMonth.month,
+          firstDayOfWeekFromSunday);
+      if (firstDayOffset == 0) return result;
+
+
+      int prevMonth = curMonth.month - 1;
+      if (prevMonth < 1) prevMonth = 12;
+
+      int prevYear = prevMonth == 12
+        ? curMonth.year - 1
+        : curMonth.year;
+
+      int daysInPrevMonth = getDaysInMonth(prevYear, prevMonth);
+      int firstShownDay = daysInPrevMonth - firstDayOffset + 1;
+      result = DateTime(prevYear, prevMonth, firstShownDay);
+    }
+
+    return result;
+  }
+
+
+  /// Returns last shown date for the [curMonth].
+  ///
+  /// Last shown date is not always last day of the [curMonth].
+  /// It can be day from next month if [showStartNextMonth] is true.
+  ///
+  /// If [showStartNextMonth] is true empty day cells after last day
+  /// of [curMonth] are filled with days from the next month.
+  static DateTime lastShownDate({
+      required DateTime curMonth,
+      required bool showStartNextMonth,
+      required int firstDayOfWeekFromSunday}) {
+
+    int daysInCurMonth = getDaysInMonth(curMonth.year, curMonth.month);
+    DateTime result = DateTime(curMonth.year, curMonth.month, daysInCurMonth);
+
+    if (showStartNextMonth) {
+      int firstDayOffset = computeFirstDayOffset(curMonth.year, curMonth.month,
+          firstDayOfWeekFromSunday);
+
+      int totalDays = firstDayOffset + daysInCurMonth;
+      int trailingDaysCount = 7 - totalDays % 7;
+      bool fullWeekTrailing = trailingDaysCount == 7;
+      if (fullWeekTrailing) return result;
+
+      result = DateTime(curMonth.year, curMonth.month + 1, trailingDaysCount);
+    }
+
+    return result;
+  }
+
+  /// Computes the offset from the first day of week that the first day of the
+  /// [month] falls on.
+  ///
+  /// For example, September 1, 2017 falls on a Friday, which in the calendar
+  /// localized for United States English appears as:
+  ///
+  /// ```
+  /// S M T W T F S
+  /// _ _ _ _ _ 1 2
+  /// ```
+  ///
+  /// The offset for the first day of the months is the number of leading blanks
+  /// in the calendar, i.e. 5.
+  ///
+  /// The same date localized for the Russian calendar has a different offset,
+  /// because the first day of week is Monday rather than Sunday:
+  ///
+  /// ```
+  /// M T W T F S S
+  /// _ _ _ _ 1 2 3
+  /// ```
+  ///
+  /// So the offset is 4, rather than 5.
+  ///
+  /// This code consolidates the following:
+  ///
+  /// - [DateTime.weekday] provides a 1-based index into days of week, with 1
+  ///   falling on Monday.
+  /// - MaterialLocalizations.firstDayOfWeekIndex provides a 0-based index
+  ///   into the MaterialLocalizations.narrowWeekdays list.
+  /// - MaterialLocalizations.narrowWeekdays list provides localized names of
+  ///   days of week, always starting with Sunday and ending with Saturday.
+  static int computeFirstDayOffset(
+      int year, int month, int firstDayOfWeekFromSunday) {
+    // 0-based day of week, with 0 representing Monday.
+    final int weekdayFromMonday = DateTime(year, month).weekday - 1;
+    // firstDayOfWeekFromSunday recomputed to be Monday-based
+    final int firstDayOfWeekFromMonday = (firstDayOfWeekFromSunday - 1) % 7;
+    // Number of days between the first day of week appearing on the calendar,
+    // and the day corresponding to the 1-st of the month.
+    return (weekdayFromMonday - firstDayOfWeekFromMonday) % 7;
+  }
+
+  /// Returns earliest [DateTime] from the list.
+  ///
+  /// [dates] must not be null.
+  /// In case it is null, [ArgumentError] will be thrown.
+  static DateTime getEarliestFromList(List<DateTime> dates) {
+    ArgumentError.checkNotNull(dates, "dates");
+
+    return dates.fold(dates[0], getEarliest);
+  }
+
+  /// Returns earliest [DateTime] from two.
+  ///
+  /// If two [DateTime]s is the same moment first ([a]) will be return.
+  static DateTime getEarliest(DateTime a, DateTime b)
+    => a.isBefore(b) ? a : b;
+}

flutter_date_pickers-master/lib/src/week_picker.dart

@@ -0,0 +1,117 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+
+import 'date_period.dart';
+import 'date_picker_keys.dart';
+import 'date_picker_styles.dart';
+import 'day_based_changable_picker.dart';
+import 'day_picker_selection.dart';
+import 'day_type.dart';
+import 'event_decoration.dart';
+import 'i_selectable_picker.dart';
+import 'layout_settings.dart';
+import 'typedefs.dart';
+
+/// Date picker for selection a week.
+class WeekPicker extends StatelessWidget {
+  /// Creates a month picker.
+  WeekPicker(
+      {Key? key,
+      required this.selectedDate,
+      required this.onChanged,
+      required this.firstDate,
+      required this.lastDate,
+      this.initiallyShowDate,
+      this.datePickerLayoutSettings = const DatePickerLayoutSettings(),
+      this.datePickerStyles,
+      this.datePickerKeys,
+      this.selectableDayPredicate,
+      this.onSelectionError,
+      this.eventDecorationBuilder,
+      this.onMonthChanged})
+      : assert(!firstDate.isAfter(lastDate)),
+        assert(!lastDate.isBefore(firstDate)),
+        assert(!selectedDate.isBefore(firstDate)),
+        assert(!selectedDate.isAfter(lastDate)),
+        assert(initiallyShowDate == null
+            || !initiallyShowDate.isAfter(lastDate)),
+        assert(initiallyShowDate == null
+            || !initiallyShowDate.isBefore(firstDate)),
+        super(key: key);
+
+  /// The currently selected date.
+  ///
+  /// This date is highlighted in the picker.
+  final DateTime selectedDate;
+
+  /// Called when the user picks a week.
+  final ValueChanged<DatePeriod> onChanged;
+
+  /// Called when the error was thrown after user selection.
+  /// (e.g. when user selected a week with one or more days
+  /// what can't be selected)
+  final OnSelectionError? onSelectionError;
+
+  /// The earliest date the user is permitted to pick.
+  final DateTime firstDate;
+
+  /// The latest date the user is permitted to pick.
+  final DateTime lastDate;
+
+  /// Date for defining what month should be shown initially.
+  ///
+  /// In case of null month with earliest date of the selected week
+  /// will be shown.
+  final DateTime? initiallyShowDate;
+
+  /// Layout settings what can be customized by user
+  final DatePickerLayoutSettings datePickerLayoutSettings;
+
+  /// Some keys useful for integration tests
+  final DatePickerKeys? datePickerKeys;
+
+  /// Styles what can be customized by user
+  final DatePickerRangeStyles? datePickerStyles;
+
+  /// Function returns if day can be selected or not.
+  final SelectableDayPredicate? selectableDayPredicate;
+
+  /// Builder to get event decoration for each date.
+  ///
+  /// All event styles are overriden by selected styles
+  /// except days with dayType is [DayType.notSelected].
+  final EventDecorationBuilder? eventDecorationBuilder;
+
+  /// Called when the user changes the month.
+  /// New DateTime object represents first day of new month and 00:00 time.
+  final ValueChanged<DateTime>? onMonthChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    MaterialLocalizations localizations = MaterialLocalizations.of(context);
+
+    int firstDayOfWeekIndex = datePickerStyles?.firstDayOfeWeekIndex ??
+        localizations.firstDayOfWeekIndex;
+
+    ISelectablePicker<DatePeriod> weekSelectablePicker = WeekSelectable(
+        selectedDate, firstDayOfWeekIndex, firstDate, lastDate,
+        selectableDayPredicate: selectableDayPredicate);
+
+    return DayBasedChangeablePicker<DatePeriod>(
+      selectablePicker: weekSelectablePicker,
+      // todo: maybe create selection for week
+      // todo: and change logic here to work with it
+      selection: DayPickerSingleSelection(selectedDate),
+      firstDate: firstDate,
+      lastDate: lastDate,
+      initiallyShownDate: initiallyShowDate,
+      onChanged: onChanged,
+      onSelectionError: onSelectionError,
+      datePickerLayoutSettings: datePickerLayoutSettings,
+      datePickerStyles: datePickerStyles ?? DatePickerRangeStyles(),
+      datePickerKeys: datePickerKeys,
+      eventDecorationBuilder: eventDecorationBuilder,
+      onMonthChanged: onMonthChanged,
+    );
+  }
+}