chore: modernize Flutter examples — null safety, latest APIs, Kotlin DSL Gradle (#148)

* updates

* Update Gradle wrapper script to fetch latest version online and allow --version override

* chore(analytics_integration): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build files to Kotlin DSL and bump Gradle wrapper.

* chore(animation_example): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build files to Kotlin DSL.

* chore(biometrics): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build files to Kotlin DSL.

* chore(bmi_calculator): test

test body

* chore(bottom_sheet): test

test body

* chore(custom_home_drawer): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build files to Kotlin DSL and bump Gradle wrapper.

* chore(covid19_mobile_app): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(dropdown_button): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(enabling_splash_screen): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(expense_planner): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(firebase_crash_reporting): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(firebase_google_authentication): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(flutter_date_pickers-master): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(getx_counter_app): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(google_signin): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(grid_layout): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(handling_routes): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(image_editor): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(image_from_network): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(infinite_list): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(load_local_image): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(load_local_json): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(lunch_app): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(navigation_drawer): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(news_memes_app): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(persist_key_value): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(push_notifications): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(save_data_locally_with_sqlite): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(scan_qr_code): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(simple_material_app): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(sliver_app_bar_example): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(stateful_widget): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(stateless_widgets): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(statless_counter_app): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(tic_tac_toe): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(tip_calculator): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(todo_list_using_provider): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(unit_testing): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_alert_dialog): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_bottom_nav_bar): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_custom_fonts): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_edittext): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_expansionpanel): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_firebase_db): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_gradient): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_http_get): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_interactiveviewer): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_listview): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_listwheelscrollview): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_platform_adaptive): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore(using_snackbar): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_stepper): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_tabs): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(using_theme): remove legacy nested android project

Delete the redundant nested android/ project directory from the old layout. Also update pubspec.yaml SDK constraints and dependencies.

* chore(view_pdf_file): migrate Gradle build scripts to Kotlin DSL

Convert Groovy build.gradle/settings.gradle to Kotlin DSL and bump Gradle wrapper.

* chore: ignore .trash directory

* chore: remove IDE configs and PR template

* chore(infinite_list): remove legacy nested android project

* refactor(infinite_list): migrate theme to ColorScheme API

* refactor(using_theme): migrate to ColorScheme API

* refactor(analytics_integration): migrate Firebase Analytics API

* refactor(firebase_google_authentication): migrate Google Sign-In API

* refactor(covid19_mobile_app): migrate theme and buttons to current API

* refactor(covid19_mobile_app): replace bezier_chart with fl_chart

* refactor(image_editor): migrate image plugins and button styles

* refactor(scan_qr_code): migrate mobile_scanner API

* refactor(lunch_app): migrate to null safety

* refactor(todo_list_using_provider): migrate to null safety

* refactor(unit_testing): migrate to null safety

* refactor(using_firebase_db): migrate Firebase Database API

* fix(update_gradle_wrapper): edit gradle-wrapper.properties directly

* refactor(push_notifications): migrate Firebase Messaging API

* refactor(using_http_get): migrate to null safety

* refactor(using_listview): migrate to null safety

* refactor(using_listwheelscrollview): migrate to null safety

* refactor(view_pdf_file): migrate to null safety

* refactor(bottom_sheet): migrate to null safety

* refactor(stateless_widgets): migrate to null safety

* chore: regenerate Gradle wrapper

* refactor: move maintenance scripts to Makefile

* chore: remove generated and IDE files

* fix: migrate image_editor to current plugins

* fix: migrate news_memes_app share to share_plus

* fix: migrate view_pdf_file to syncfusion pdf viewer

* fix: update deprecated APIs

* style: remove commented-out code

flutter_date_pickers-master/lib/src/date_picker_styles.dart

@@ -84,18 +84,18 @@ class DatePickerStyles {
   /// Return new [DatePickerStyles] object where fields
   /// with null values set with defaults from theme.
   DatePickerStyles fulfillWithTheme(ThemeData theme) {
-    Color accentColor = theme.accentColor;
+    Color accentColor = theme.colorScheme.secondary;
 
     TextStyle? _displayedPeriodTitle =
-        displayedPeriodTitle ?? theme.textTheme.subtitle1;
+        displayedPeriodTitle ?? theme.textTheme.titleMedium;
     TextStyle? _currentDateStyle = currentDateStyle ??
-        theme.textTheme.bodyText1?.copyWith(color: theme.accentColor);
+        theme.textTheme.bodyLarge?.copyWith(color: theme.colorScheme.secondary);
     TextStyle? _disabledDateStyle = disabledDateStyle ??
-        theme.textTheme.bodyText2?.copyWith(color: theme.disabledColor);
+        theme.textTheme.bodyMedium?.copyWith(color: theme.disabledColor);
     TextStyle? _selectedDateStyle =
-        selectedDateStyle ?? theme.accentTextTheme.bodyText1;
+        selectedDateStyle ?? theme.textTheme.bodyLarge;
     TextStyle? _defaultDateTextStyle =
-        defaultDateTextStyle ?? theme.textTheme.bodyText2;
+        defaultDateTextStyle ?? theme.textTheme.bodyMedium;
     BoxDecoration _selectedSingleDateDecoration =
         selectedSingleDateDecoration ??
             BoxDecoration(
@@ -104,7 +104,7 @@ class DatePickerStyles {
 
     DayHeaderStyle? _dayHeaderStyle = dayHeaderStyle;
     if (dayHeaderStyleBuilder == null && _dayHeaderStyle == null) {
-      _dayHeaderStyle = DayHeaderStyle(textStyle: theme.textTheme.caption);
+      _dayHeaderStyle = DayHeaderStyle(textStyle: theme.textTheme.bodySmall);
     }
 
     return DatePickerStyles(
@@ -142,7 +142,7 @@ class DatePickerStyles {
 
   @override
   int get hashCode =>
-     hashValues(
+     Object.hash(
         displayedPeriodTitle,
         currentDateStyle,
         disabledDateStyle,
@@ -210,7 +210,7 @@ class DatePickerRangeStyles extends DatePickerStyles {
   /// where fields with null values set with defaults from given theme.
   @override
   DatePickerRangeStyles fulfillWithTheme(ThemeData theme) {
-    Color accentColor = theme.accentColor;
+    Color accentColor = theme.colorScheme.secondary;
 
     DatePickerStyles commonStyles = super.fulfillWithTheme(theme);
 
@@ -328,7 +328,7 @@ class DatePickerRangeStyles extends DatePickerStyles {
 
   @override
   int get hashCode =>
-     hashValues(
+     Object.hash(
       selectedPeriodStartDecoration,
       selectedPeriodStartTextStyle,
       selectedPeriodLastDecoration,
@@ -353,7 +353,7 @@ class DatePickerRangeStyles extends DatePickerStyles {
 /// User styles for the day header in date picker.
 @immutable
 class DayHeaderStyle {
-  /// If null - textTheme.caption from the Theme will be used.
+  /// If null - textTheme.bodySmall from the Theme will be used.
   final TextStyle? textStyle;
 
   /// If null - no decoration will be applied for the day header;
@@ -379,7 +379,7 @@ class DayHeaderStyle {
   }
 
   @override
-  int get hashCode => hashValues(
+  int get hashCode => Object.hash(
       textStyle,
       decoration
     );