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samples/gallery/lib/demos/material/sliders_demo.dart
2020-02-05 14:11:54 -05:00

504 lines
15 KiB
Dart

// Copyright 2019 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:gallery/l10n/gallery_localizations.dart';
enum SlidersDemoType {
sliders,
rangeSliders,
customSliders,
}
class SlidersDemo extends StatelessWidget {
const SlidersDemo({Key key, this.type}) : super(key: key);
final SlidersDemoType type;
String _title(BuildContext context) {
switch (type) {
case SlidersDemoType.sliders:
return GalleryLocalizations.of(context).demoSlidersTitle;
case SlidersDemoType.rangeSliders:
return GalleryLocalizations.of(context).demoRangeSlidersTitle;
case SlidersDemoType.customSliders:
return GalleryLocalizations.of(context).demoCustomSlidersTitle;
}
return '';
}
@override
Widget build(BuildContext context) {
Widget sliders;
switch (type) {
case SlidersDemoType.sliders:
sliders = _Sliders();
break;
case SlidersDemoType.rangeSliders:
sliders = _RangeSliders();
break;
case SlidersDemoType.customSliders:
sliders = _CustomSliders();
}
return Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: Text(_title(context)),
),
body: sliders,
);
}
}
// BEGIN slidersDemo
class _Sliders extends StatefulWidget {
@override
_SlidersState createState() => _SlidersState();
}
class _SlidersState extends State<_Sliders> {
double _continuousValue = 25;
double _discreteValue = 20;
@override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 40),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Column(
mainAxisSize: MainAxisSize.min,
children: [
Semantics(
label: GalleryLocalizations.of(context)
.demoSlidersEditableNumericalValue,
child: SizedBox(
width: 64,
height: 48,
child: TextField(
textAlign: TextAlign.center,
onSubmitted: (value) {
final double newValue = double.tryParse(value);
if (newValue != null && newValue != _continuousValue) {
setState(() {
_continuousValue = newValue.clamp(0, 100) as double;
});
}
},
keyboardType: TextInputType.number,
controller: TextEditingController(
text: _continuousValue.toStringAsFixed(0),
),
),
),
),
Slider(
value: _continuousValue,
min: 0,
max: 100,
onChanged: (value) {
setState(() {
_continuousValue = value;
});
},
),
Text(GalleryLocalizations.of(context)
.demoSlidersContinuousWithEditableNumericalValue),
],
),
const SizedBox(height: 80),
Column(
mainAxisSize: MainAxisSize.min,
children: [
Slider(
value: _discreteValue,
min: 0,
max: 200,
divisions: 5,
label: _discreteValue.round().toString(),
onChanged: (value) {
setState(() {
_discreteValue = value;
});
},
),
Text(GalleryLocalizations.of(context).demoSlidersDiscrete),
],
),
],
),
);
}
}
// END
// BEGIN rangeSlidersDemo
class _RangeSliders extends StatefulWidget {
@override
_RangeSlidersState createState() => _RangeSlidersState();
}
class _RangeSlidersState extends State<_RangeSliders> {
RangeValues _continuousValues = const RangeValues(25, 75);
RangeValues _discreteValues = const RangeValues(40, 120);
@override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 40),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Column(
mainAxisSize: MainAxisSize.min,
children: [
RangeSlider(
values: _continuousValues,
min: 0,
max: 100,
onChanged: (values) {
setState(() {
_continuousValues = values;
});
},
),
Text(GalleryLocalizations.of(context).demoSlidersContinuous),
],
),
const SizedBox(height: 80),
Column(
mainAxisSize: MainAxisSize.min,
children: [
RangeSlider(
values: _discreteValues,
min: 0,
max: 200,
divisions: 5,
labels: RangeLabels(
_discreteValues.start.round().toString(),
_discreteValues.end.round().toString(),
),
onChanged: (values) {
setState(() {
_discreteValues = values;
});
},
),
Text(GalleryLocalizations.of(context).demoSlidersDiscrete),
],
),
],
),
);
}
}
// END
// BEGIN customSlidersDemo
Path _downTriangle(double size, Offset thumbCenter, {bool invert = false}) {
final thumbPath = Path();
final height = math.sqrt(3) / 2;
final centerHeight = size * height / 3;
final halfSize = size / 2;
final sign = invert ? -1 : 1;
thumbPath.moveTo(
thumbCenter.dx - halfSize, thumbCenter.dy + sign * centerHeight);
thumbPath.lineTo(thumbCenter.dx, thumbCenter.dy - 2 * sign * centerHeight);
thumbPath.lineTo(
thumbCenter.dx + halfSize, thumbCenter.dy + sign * centerHeight);
thumbPath.close();
return thumbPath;
}
Path _rightTriangle(double size, Offset thumbCenter, {bool invert = false}) {
final thumbPath = Path();
final halfSize = size / 2;
final sign = invert ? -1 : 1;
thumbPath.moveTo(thumbCenter.dx + halfSize * sign, thumbCenter.dy);
thumbPath.lineTo(thumbCenter.dx - halfSize * sign, thumbCenter.dy - size);
thumbPath.lineTo(thumbCenter.dx - halfSize * sign, thumbCenter.dy + size);
thumbPath.close();
return thumbPath;
}
Path _upTriangle(double size, Offset thumbCenter) =>
_downTriangle(size, thumbCenter, invert: true);
Path _leftTriangle(double size, Offset thumbCenter) =>
_rightTriangle(size, thumbCenter, invert: true);
class _CustomRangeThumbShape extends RangeSliderThumbShape {
static const double _thumbSize = 4;
static const double _disabledThumbSize = 3;
@override
Size getPreferredSize(bool isEnabled, bool isDiscrete) {
return isEnabled
? const Size.fromRadius(_thumbSize)
: const Size.fromRadius(_disabledThumbSize);
}
static final Animatable<double> sizeTween = Tween<double>(
begin: _disabledThumbSize,
end: _thumbSize,
);
@override
void paint(
PaintingContext context,
Offset center, {
@required Animation<double> activationAnimation,
@required Animation<double> enableAnimation,
bool isDiscrete = false,
bool isEnabled = false,
bool isOnTop,
@required SliderThemeData sliderTheme,
TextDirection textDirection,
Thumb thumb,
}) {
final canvas = context.canvas;
final colorTween = ColorTween(
begin: sliderTheme.disabledThumbColor,
end: sliderTheme.thumbColor,
);
final size = _thumbSize * sizeTween.evaluate(enableAnimation);
Path thumbPath;
switch (textDirection) {
case TextDirection.rtl:
switch (thumb) {
case Thumb.start:
thumbPath = _rightTriangle(size, center);
break;
case Thumb.end:
thumbPath = _leftTriangle(size, center);
break;
}
break;
case TextDirection.ltr:
switch (thumb) {
case Thumb.start:
thumbPath = _leftTriangle(size, center);
break;
case Thumb.end:
thumbPath = _rightTriangle(size, center);
break;
}
break;
}
canvas.drawPath(
thumbPath,
Paint()..color = colorTween.evaluate(enableAnimation),
);
}
}
class _CustomThumbShape extends SliderComponentShape {
static const double _thumbSize = 4;
static const double _disabledThumbSize = 3;
@override
Size getPreferredSize(bool isEnabled, bool isDiscrete) {
return isEnabled
? const Size.fromRadius(_thumbSize)
: const Size.fromRadius(_disabledThumbSize);
}
static final Animatable<double> sizeTween = Tween<double>(
begin: _disabledThumbSize,
end: _thumbSize,
);
@override
void paint(
PaintingContext context,
Offset thumbCenter, {
Animation<double> activationAnimation,
Animation<double> enableAnimation,
bool isDiscrete,
TextPainter labelPainter,
RenderBox parentBox,
SliderThemeData sliderTheme,
TextDirection textDirection,
double value,
}) {
final canvas = context.canvas;
final colorTween = ColorTween(
begin: sliderTheme.disabledThumbColor,
end: sliderTheme.thumbColor,
);
final size = _thumbSize * sizeTween.evaluate(enableAnimation);
final thumbPath = _downTriangle(size, thumbCenter);
canvas.drawPath(
thumbPath,
Paint()..color = colorTween.evaluate(enableAnimation),
);
}
}
class _CustomValueIndicatorShape extends SliderComponentShape {
static const double _indicatorSize = 4;
static const double _disabledIndicatorSize = 3;
static const double _slideUpHeight = 40;
@override
Size getPreferredSize(bool isEnabled, bool isDiscrete) {
return Size.fromRadius(isEnabled ? _indicatorSize : _disabledIndicatorSize);
}
static final Animatable<double> sizeTween = Tween<double>(
begin: _disabledIndicatorSize,
end: _indicatorSize,
);
@override
void paint(
PaintingContext context,
Offset thumbCenter, {
Animation<double> activationAnimation,
Animation<double> enableAnimation,
bool isDiscrete,
TextPainter labelPainter,
RenderBox parentBox,
SliderThemeData sliderTheme,
TextDirection textDirection,
double value,
}) {
final canvas = context.canvas;
final enableColor = ColorTween(
begin: sliderTheme.disabledThumbColor,
end: sliderTheme.valueIndicatorColor,
);
final slideUpTween = Tween<double>(
begin: 0,
end: _slideUpHeight,
);
final size = _indicatorSize * sizeTween.evaluate(enableAnimation);
final slideUpOffset =
Offset(0, -slideUpTween.evaluate(activationAnimation));
final thumbPath = _upTriangle(size, thumbCenter + slideUpOffset);
final paintColor = enableColor
.evaluate(enableAnimation)
.withAlpha((255 * activationAnimation.value).round());
canvas.drawPath(
thumbPath,
Paint()..color = paintColor,
);
canvas.drawLine(
thumbCenter,
thumbCenter + slideUpOffset,
Paint()
..color = paintColor
..style = PaintingStyle.stroke
..strokeWidth = 2);
labelPainter.paint(
canvas,
thumbCenter +
slideUpOffset +
Offset(-labelPainter.width / 2, -labelPainter.height - 4),
);
}
}
class _CustomSliders extends StatefulWidget {
@override
_CustomSlidersState createState() => _CustomSlidersState();
}
class _CustomSlidersState extends State<_CustomSliders> {
double _discreteCustomValue = 25;
RangeValues _continuousCustomValues = const RangeValues(40, 160);
@override
Widget build(BuildContext context) {
final theme = Theme.of(context);
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 40),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Column(
mainAxisSize: MainAxisSize.min,
children: [
SliderTheme(
data: theme.sliderTheme.copyWith(
activeTrackColor: Colors.deepPurple,
inactiveTrackColor:
theme.colorScheme.onSurface.withOpacity(0.5),
activeTickMarkColor:
theme.colorScheme.onSurface.withOpacity(0.7),
inactiveTickMarkColor:
theme.colorScheme.surface.withOpacity(0.7),
overlayColor: theme.colorScheme.onSurface.withOpacity(0.12),
thumbColor: Colors.deepPurple,
valueIndicatorColor: Colors.deepPurpleAccent,
thumbShape: _CustomThumbShape(),
valueIndicatorShape: _CustomValueIndicatorShape(),
valueIndicatorTextStyle: theme.accentTextTheme.body2
.copyWith(color: theme.colorScheme.onSurface),
),
child: Slider(
value: _discreteCustomValue,
min: 0,
max: 200,
divisions: 5,
semanticFormatterCallback: (value) =>
value.round().toString(),
label: '${_discreteCustomValue.round()}',
onChanged: (value) {
setState(() {
_discreteCustomValue = value;
});
},
),
),
Text(GalleryLocalizations.of(context)
.demoSlidersDiscreteSliderWithCustomTheme),
],
),
const SizedBox(height: 80),
Column(
mainAxisSize: MainAxisSize.min,
children: [
SliderTheme(
data: SliderThemeData(
activeTrackColor: Colors.deepPurple,
inactiveTrackColor: Colors.black26,
activeTickMarkColor: Colors.white70,
inactiveTickMarkColor: Colors.black,
overlayColor: Colors.black12,
thumbColor: Colors.deepPurple,
rangeThumbShape: _CustomRangeThumbShape(),
showValueIndicator: ShowValueIndicator.never,
),
child: RangeSlider(
values: _continuousCustomValues,
min: 0,
max: 200,
onChanged: (values) {
setState(() {
_continuousCustomValues = values;
});
},
),
),
Text(GalleryLocalizations.of(context)
.demoSlidersContinuousRangeSliderWithCustomTheme),
],
),
],
),
);
}
}
// END