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Slight cleanup in PointerSignalResolver docs (#78817)

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Todd Volkert 2021-03-22 23:30:00 -07:00 committed by GitHub
parent 720dac5438
commit 5d37734ea1
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1 changed files with 74 additions and 60 deletions
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134
packages/flutter/lib/src/gestures/pointer_signal_resolver.dart
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@ -29,7 +29,6 @@ bool _isSameEvent(PointerSignalEvent event1, PointerSignalEvent event2) {
///
/// To use this class, objects should register their event handler like so:
///
/// {@tool snippet}
/// ```dart
/// void handleSignalEvent(PointerSignalEvent event) {
/// GestureBinding.instance!.pointerSignalResolver.register(event, (PointerSignalEvent event) {
@ -37,85 +36,100 @@ bool _isSameEvent(PointerSignalEvent event1, PointerSignalEvent event2) {
/// });
/// }
/// ```
/// {@end-tool}
///
/// {@tool dartpad --template=stateful_widget_material}
/// Here is an example that demonstrates the effect of not using the resolver
/// versus using it.
///
/// When this example is set to _not_ use the resolver, then scrolling the
/// When this example is set to _not_ use the resolver, then triggering the
/// mouse wheel over the outer box will cause only the outer box to change
/// color, but scrolling the mouse wheel over inner box will cause _both_ the
/// outer and the inner boxes to change color (because they're both receiving
/// the scroll event).
/// color, but triggering the mouse wheel over the inner box will cause _both_
/// the outer and the inner boxes to change color (because they're both
/// receiving the event).
///
/// When this excample is set to _use_ the resolver, then only the box located
/// When this example is set to _use_ the resolver, then only the box located
/// directly under the cursor will change color when the mouse wheel is
/// scrolled.
/// triggered.
///
/// ```dart imports
/// import 'package:flutter/gestures.dart';
/// ```
///
/// ```dart preamble
/// class ColorChanger extends StatefulWidget {
/// const ColorChanger({
/// Key? key,
/// required this.initialColor,
/// required this.useResolver,
/// required this.child,
/// }) : super(key: key);
///
/// final HSVColor initialColor;
/// final bool useResolver;
/// final Widget child;
///
/// @override
/// _ColorChangerState createState() => _ColorChangerState();
/// }
///
/// class _ColorChangerState extends State<ColorChanger> {
/// late HSVColor color;
///
/// void rotateColor() {
/// setState(() {
/// color = color.withHue((color.hue + 6) % 360.0);
/// });
/// }
///
/// @override
/// void initState() {
/// super.initState();
/// color = widget.initialColor;
/// }
///
/// @override
/// Widget build(BuildContext context) {
/// return DecoratedBox(
/// decoration: BoxDecoration(
/// border: const Border.fromBorderSide(BorderSide()),
/// color: color.toColor(),
/// ),
/// child: Listener(
/// onPointerSignal: (PointerSignalEvent event) {
/// if (widget.useResolver) {
/// GestureBinding.instance!.pointerSignalResolver.register(event, (PointerSignalEvent event) {
/// rotateColor();
/// });
/// } else {
/// rotateColor();
/// }
/// },
/// child: widget.child,
/// ),
/// );
/// }
/// }
/// ```
///
/// ```dart
/// HSVColor outerColor = const HSVColor.fromAHSV(0.2, 120.0, 1, 1);
/// HSVColor innerColor = const HSVColor.fromAHSV(1, 60.0, 1, 1);
/// bool useResolver = false;
///
/// void rotateOuterColor() {
/// setState(() {
/// outerColor = outerColor.withHue((outerColor.hue + 6) % 360.0);
/// });
/// }
///
/// void rotateInnerColor() {
/// setState(() {
/// innerColor = innerColor.withHue((innerColor.hue + 6) % 360.0);
/// });
/// }
///
/// @override
/// Widget build(BuildContext context) {
/// return Material(
/// child: Stack(
/// fit: StackFit.expand,
/// children: <Widget>[
/// Listener(
/// onPointerSignal: (PointerSignalEvent event) {
/// if (useResolver) {
/// GestureBinding.instance!.pointerSignalResolver.register(event, (PointerSignalEvent event) {
/// rotateOuterColor();
/// });
/// } else {
/// rotateOuterColor();
/// }
/// },
/// child: DecoratedBox(
/// decoration: BoxDecoration(
/// border: const Border.fromBorderSide(BorderSide()),
/// color: outerColor.toColor(),
/// ),
/// child: FractionallySizedBox(
/// widthFactor: 0.5,
/// heightFactor: 0.5,
/// child: DecoratedBox(
/// decoration: BoxDecoration(
/// border: const Border.fromBorderSide(BorderSide()),
/// color: innerColor.toColor(),
/// ),
/// child: Listener(
/// onPointerSignal: (PointerSignalEvent event) {
/// if (useResolver) {
/// GestureBinding.instance!.pointerSignalResolver.register(event, (PointerSignalEvent event) {
/// rotateInnerColor();
/// });
/// } else {
/// rotateInnerColor();
/// }
/// },
/// child: const AbsorbPointer(),
/// ),
/// ),
/// ColorChanger(
/// initialColor: const HSVColor.fromAHSV(0.2, 120.0, 1, 1),
/// useResolver: useResolver,
/// child: FractionallySizedBox(
/// widthFactor: 0.5,
/// heightFactor: 0.5,
/// child: ColorChanger(
/// initialColor: const HSVColor.fromAHSV(1, 60.0, 1, 1),
/// useResolver: useResolver,
/// child: const AbsorbPointer(),
/// ),
/// ),
/// ),
@ -132,9 +146,9 @@ bool _isSameEvent(PointerSignalEvent event1, PointerSignalEvent event2) {
/// });
/// },
/// ),
/// Text(
/// const Text(
/// 'Use the PointerSignalResolver?',
/// style: DefaultTextStyle.of(context).style.copyWith(fontWeight: FontWeight.bold),
/// style: TextStyle(fontWeight: FontWeight.bold),
/// ),
/// ],
/// ),