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112 行
3.7 KiB

using System;
using Unity.UIWidgets.animation;
using Unity.UIWidgets.async;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.ui;
using Unity.UIWidgets.widgets;
namespace Unity.UIWidgets.material {
static class ScrollbarUtils {
public static readonly TimeSpan _kScrollbarFadeDuration = TimeSpan.FromMilliseconds(300);
public static readonly TimeSpan _kScrollbarTimeToFade = TimeSpan.FromMilliseconds(600);
public const float _kScrollbarThickness = 6.0f;
}
public class Scrollbar : StatefulWidget {
public Scrollbar(
Key key = null,
Widget child = null) : base(key: key) {
this.child = child;
}
public readonly Widget child;
public override State createState() {
return new _ScrollbarState();
}
}
public class _ScrollbarState : TickerProviderStateMixin<Scrollbar> {
public ScrollbarPainter _materialPainter;
public TextDirection _textDirection;
public Color _themeColor;
public AnimationController _fadeoutAnimationController;
public Animation<float> _FadeoutOpacityAnimation;
public Timer _fadeoutTimer;
public override void initState() {
base.initState();
_fadeoutAnimationController = new AnimationController(
vsync: this,
duration: ScrollbarUtils._kScrollbarFadeDuration
);
_FadeoutOpacityAnimation = new CurvedAnimation(
parent: _fadeoutAnimationController,
curve: Curves.fastOutSlowIn
);
}
public override void didChangeDependencies() {
base.didChangeDependencies();
ThemeData theme = Theme.of(context);
_themeColor = theme.highlightColor.withOpacity(1.0f);
_textDirection = Directionality.of(context);
_materialPainter = _BuildMaterialScrollbarPainter();
}
public ScrollbarPainter _BuildMaterialScrollbarPainter() {
return new ScrollbarPainter(
color: _themeColor,
textDirection: _textDirection,
thickness: ScrollbarUtils._kScrollbarThickness,
fadeoutOpacityAnimation: _FadeoutOpacityAnimation
);
}
bool _handleScrollNotification(ScrollNotification notification) {
if (notification is ScrollUpdateNotification || notification is OverscrollNotification) {
if (_fadeoutAnimationController.status != AnimationStatus.forward) {
_fadeoutAnimationController.forward();
}
_materialPainter.update(notification.metrics, notification.metrics.axisDirection);
_fadeoutTimer?.cancel();
_fadeoutTimer = Window.instance.run(ScrollbarUtils._kScrollbarTimeToFade, () => {
_fadeoutAnimationController.reverse();
_fadeoutTimer = null;
});
}
return false;
}
public override void dispose() {
_fadeoutAnimationController.dispose();
_fadeoutTimer?.cancel();
_materialPainter?.dispose();
base.dispose();
}
public override Widget build(BuildContext context) {
return new NotificationListener<ScrollNotification>(
onNotification: _handleScrollNotification,
child: new RepaintBoundary(
child: new CustomPaint(
foregroundPainter: _materialPainter,
child: new RepaintBoundary(
child: widget.child
)
)
)
);
}
}
}