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Merge pull request #2829 from HansMuller/super_fling_fast

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Fix Fast Fling Failure
This commit is contained in:
Hans Muller 2016-03-22 09:53:36 -07:00
commit bcf08d2309
3 changed files with 10 additions and 8 deletions
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4
packages/flutter/lib/src/gestures/constants.dart
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@ -78,9 +78,9 @@ const double kWindowTouchSlop = 16.0; // Logical pixels
/// gesture.
// TODO(ianh): Make sure nobody has their own version of this.
const double kMinFlingVelocity = 50.0; // Logical pixels / second
// const Velocity kMinFlingVelocity = const Velocity(pixelsPerSecond: 50.0);
/// The maximum velocity of a touch to consider that touch to trigger a fling
/// gesture.
/// Drag gesture fling velocities are clipped to this value.
// TODO(ianh): Make sure nobody has their own version of this.
const double kMaxFlingVelocity = 8000.0; // Logical pixels / second

11
packages/flutter/lib/src/gestures/drag.dart
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@ -31,8 +31,7 @@ typedef void _GesturePolymorphicUpdateCallback<T>(T delta);
bool _isFlingGesture(Velocity velocity) {
assert(velocity != null);
final double speedSquared = velocity.pixelsPerSecond.distanceSquared;
return speedSquared > kMinFlingVelocity * kMinFlingVelocity
&& speedSquared < kMaxFlingVelocity * kMaxFlingVelocity;
return speedSquared > kMinFlingVelocity * kMinFlingVelocity;
}
abstract class _DragGestureRecognizer<T extends dynamic> extends OneSequenceGestureRecognizer {
@ -119,10 +118,14 @@ abstract class _DragGestureRecognizer<T extends dynamic> extends OneSequenceGest
assert(tracker != null);
Velocity velocity = tracker.getVelocity();
if (velocity != null && _isFlingGesture(velocity))
if (velocity != null && _isFlingGesture(velocity)) {
final Offset pixelsPerSecond = velocity.pixelsPerSecond;
if (pixelsPerSecond.distanceSquared > kMaxFlingVelocity * kMaxFlingVelocity)
velocity = new Velocity(pixelsPerSecond: (pixelsPerSecond / pixelsPerSecond.distance) * kMaxFlingVelocity);
onEnd(velocity);
else
} else {
onEnd(Velocity.zero);
}
}
_velocityTrackers.clear();
}

3
packages/flutter/lib/src/widgets/scrollable.dart
View File

@ -499,8 +499,7 @@ abstract class ScrollableState<T extends Scrollable> extends State<T> {
Future<Null> _handleDragEnd(Velocity velocity) {
double scrollVelocity = pixelDeltaToScrollOffset(velocity.pixelsPerSecond) / Duration.MILLISECONDS_PER_SECOND;
// The gesture velocity properties are pixels/second, config min,max limits are pixels/ms
return fling(scrollVelocity.clamp(-kMaxFlingVelocity, kMaxFlingVelocity)).then(_endScroll);
return fling(scrollVelocity).then(_endScroll);
}
Null _endScroll([Null _]) {