71 lines
2.6 KiB
Dart
71 lines
2.6 KiB
Dart
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part of 'wonders_home_screen.dart';
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class _VerticalSwipeController {
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_VerticalSwipeController(this.ticker, this.onSwipeComplete);
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final TickerProvider ticker;
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final swipeAmt = ValueNotifier<double>(0);
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final isPointerDown = ValueNotifier<bool>(false);
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late final swipeReleaseAnim = AnimationController(vsync: ticker)..addListener(handleSwipeReleaseAnimTick);
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final double _pullToViewDetailsThreshold = 150;
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final VoidCallback onSwipeComplete;
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/// When the _swipeReleaseAnim plays, sync its value to _swipeUpAmt
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void handleSwipeReleaseAnimTick() => swipeAmt.value = swipeReleaseAnim.value;
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void handleTapDown() => isPointerDown.value = true;
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void handleTapCancelled() => isPointerDown.value = false;
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void handleVerticalSwipeCancelled() {
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swipeReleaseAnim.duration = swipeAmt.value.seconds * .5;
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swipeReleaseAnim.reverse(from: swipeAmt.value);
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isPointerDown.value = false;
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}
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void handleVerticalSwipeUpdate(DragUpdateDetails details) {
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if (swipeReleaseAnim.isAnimating) swipeReleaseAnim.stop();
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if (details.delta.dy > 0) {
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swipeAmt.value = 0;
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} else {
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isPointerDown.value = true;
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double value = (swipeAmt.value - details.delta.dy / _pullToViewDetailsThreshold).clamp(0, 1);
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if (value != swipeAmt.value) {
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swipeAmt.value = value;
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if (swipeAmt.value == 1) {
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onSwipeComplete();
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}
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}
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}
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//print(_swipeUpAmt.value);
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}
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/// Utility method to wrap a couple of ValueListenableBuilders and pass the values into a builder methods.
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/// Saves the UI some boilerplate when subscribing to changes.
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Widget buildListener(
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{required Widget Function(double swipeUpAmt, bool isPointerDown, Widget? child) builder, Widget? child}) {
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return ValueListenableBuilder<double>(
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valueListenable: swipeAmt,
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builder: (_, swipeAmt, __) => ValueListenableBuilder<bool>(
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valueListenable: isPointerDown,
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builder: (_, isPointerDown, __) {
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return builder(swipeAmt, isPointerDown, child);
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},
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),
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);
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}
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/// Utility method to wrap a gesture detector and wire up the required handlers.
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Widget wrapGestureDetector(Widget child, {Key? key}) => Semantics(
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button: false,
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child: GestureDetector(
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key: key,
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onTapDown: (_) {
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handleTapDown();
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},
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onTapUp: (_) => handleTapCancelled(),
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onVerticalDragUpdate: handleVerticalSwipeUpdate,
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onVerticalDragEnd: (_) => handleVerticalSwipeCancelled(),
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onVerticalDragCancel: handleVerticalSwipeCancelled,
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behavior: HitTestBehavior.translucent,
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child: child),
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);
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}
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