133 lines
3.8 KiB
Dart
133 lines
3.8 KiB
Dart
import 'dart:math';
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import 'package:flutter/material.dart';
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import 'package:flutter/scheduler.dart';
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class Sweeper extends StatefulWidget {
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final WidgetBuilder builder;
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final double startAngle;
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final double sweepAngle;
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final Curve curve;
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final ValueNotifier<bool> toggledNotifier;
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const Sweeper({
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Key key,
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@required this.builder,
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this.startAngle = -pi / 2,
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this.sweepAngle = pi / 4,
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this.curve = Curves.easeInOutCubic,
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@required this.toggledNotifier,
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}) : super(key: key);
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@override
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_SweeperState createState() => _SweeperState();
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}
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class _SweeperState extends State<Sweeper> with SingleTickerProviderStateMixin {
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AnimationController _angleAnimationController;
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Animation<double> _angle;
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bool _isAppearing = false;
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bool get isToggled => widget.toggledNotifier.value;
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static const opacityAnimationDurationMillis = 150;
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static const sweepingDurationMillis = 650;
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@override
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void initState() {
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super.initState();
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_angleAnimationController = AnimationController(
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duration: const Duration(milliseconds: sweepingDurationMillis),
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vsync: this,
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);
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_angle = Tween(
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begin: widget.startAngle - widget.sweepAngle / 2,
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end: widget.startAngle + pi * 2 - widget.sweepAngle / 2,
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).animate(CurvedAnimation(
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parent: _angleAnimationController,
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curve: widget.curve,
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));
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_angleAnimationController.addStatusListener(_onAnimationStatusChange);
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_registerWidget(widget);
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}
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@override
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void didUpdateWidget(Sweeper oldWidget) {
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super.didUpdateWidget(oldWidget);
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_unregisterWidget(oldWidget);
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_registerWidget(widget);
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}
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@override
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void dispose() {
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_angleAnimationController.removeStatusListener(_onAnimationStatusChange);
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_unregisterWidget(widget);
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super.dispose();
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}
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void _registerWidget(Sweeper widget) {
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widget.toggledNotifier.addListener(_onToggle);
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}
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void _unregisterWidget(Sweeper widget) {
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widget.toggledNotifier.removeListener(_onToggle);
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}
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@override
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Widget build(BuildContext context) {
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return IgnorePointer(
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child: AnimatedOpacity(
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opacity: isToggled && (_isAppearing || _angleAnimationController.status == AnimationStatus.forward) ? 1 : 0,
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duration: const Duration(milliseconds: opacityAnimationDurationMillis),
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child: ValueListenableBuilder<double>(
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valueListenable: _angleAnimationController,
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builder: (context, value, child) {
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return ClipPath(
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child: widget.builder(context),
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clipper: _SweepClipPath(
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startAngle: _angle.value,
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sweepAngle: widget.sweepAngle,
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),
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);
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}),
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),
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);
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}
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void _onAnimationStatusChange(AnimationStatus status) {
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setState(() {});
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}
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Future<void> _onToggle() async {
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if (isToggled) {
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_isAppearing = true;
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setState(() {});
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await Future.delayed(Duration(milliseconds: (opacityAnimationDurationMillis * timeDilation).toInt()));
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_isAppearing = false;
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_angleAnimationController.forward();
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} else {
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await Future.delayed(Duration(milliseconds: (opacityAnimationDurationMillis * timeDilation).toInt()));
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_angleAnimationController.reset();
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}
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setState(() {});
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}
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}
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class _SweepClipPath extends CustomClipper<Path> {
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final double startAngle;
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final double sweepAngle;
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const _SweepClipPath({@required this.startAngle, @required this.sweepAngle});
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@override
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Path getClip(Size size) {
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Path path = Path();
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path.moveTo(size.width / 2, size.height / 2);
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path.addArc(Rect.fromLTWH(0, 0, size.width, size.height), startAngle, sweepAngle);
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path.lineTo(size.width / 2, size.height / 2);
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return path;
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}
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@override
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bool shouldReclip(CustomClipper<Path> oldClipper) => true;
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}
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