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185 行
6.0 KiB

using System.Collections.Generic;
using System.Linq;
using RSG.Promises;
using UIWidgets.async;
using UIWidgets.foundation;
using UIWidgets.ui;
namespace UIWidgets.gestures {
public delegate void GestureDoubleTapCallback();
class _TapTracker {
internal _TapTracker(
PointerDownEvent evt = null,
GestureArenaEntry entry = null) {
this.pointer = evt.pointer;
this._initialPosition = evt.position;
this.entry = entry;
}
public readonly int pointer;
public readonly GestureArenaEntry entry;
readonly Offset _initialPosition;
bool _isTrackingPointer = false;
public void startTrackingPointer(PointerRoute route) {
if (!this._isTrackingPointer) {
this._isTrackingPointer = true;
GestureBinding.instance.pointerRouter.addRoute(this.pointer, route);
}
}
public void stopTrackingPointer(PointerRoute route) {
if (this._isTrackingPointer) {
this._isTrackingPointer = false;
GestureBinding.instance.pointerRouter.removeRoute(this.pointer, route);
}
}
public bool isWithinTolerance(PointerEvent evt, double tolerance) {
Offset offset = evt.position - this._initialPosition;
return offset.distance <= tolerance;
}
}
public class DoubleTapGestureRecognizer : GestureRecognizer {
public DoubleTapGestureRecognizer(object debugOwner = null)
: base(debugOwner: debugOwner) {
}
public GestureDoubleTapCallback onDoubleTap;
Timer _doubleTapTimer;
_TapTracker _firstTap;
readonly Dictionary<int, _TapTracker> _trackers = new Dictionary<int, _TapTracker>();
public override void addPointer(PointerDownEvent evt) {
if (this._firstTap != null &&
!this._firstTap.isWithinTolerance(evt, Constants.kDoubleTapSlop)) {
return;
}
this._stopDoubleTapTimer();
_TapTracker tracker = new _TapTracker(
evt: evt,
entry: GestureBinding.instance.gestureArena.add(evt.pointer, this)
);
this._trackers[evt.pointer] = tracker;
tracker.startTrackingPointer(this._handleEvent);
}
void _handleEvent(PointerEvent evt) {
_TapTracker tracker = this._trackers[evt.pointer];
D.assert(tracker != null);
if (evt is PointerUpEvent) {
if (this._firstTap == null) {
this._registerFirstTap(tracker);
} else {
this._registerSecondTap(tracker);
}
} else if (evt is PointerMoveEvent) {
if (!tracker.isWithinTolerance(evt, Constants.kDoubleTapTouchSlop)) {
this._reject(tracker);
}
} else if (evt is PointerCancelEvent) {
this._reject(tracker);
}
}
public override void acceptGesture(int pointer) {
}
public override void rejectGesture(int pointer) {
_TapTracker tracker;
this._trackers.TryGetValue(pointer, out tracker);
if (tracker == null &&
this._firstTap != null &&
this._firstTap.pointer == pointer) {
tracker = this._firstTap;
}
if (tracker != null) {
this._reject(tracker);
}
}
void _reject(_TapTracker tracker) {
this._trackers.Remove(tracker.pointer);
tracker.entry.resolve(GestureDisposition.rejected);
this._freezeTracker(tracker);
if (this._firstTap != null &&
(this._trackers.isEmpty() || tracker == this._firstTap)) {
this._reset();
}
}
public override void dispose() {
this._reset();
base.dispose();
}
void _reset() {
this._stopDoubleTapTimer();
if (this._firstTap != null) {
_TapTracker tracker = this._firstTap;
this._firstTap = null;
this._reject(tracker);
GestureBinding.instance.gestureArena.release(tracker.pointer);
}
this._clearTrackers();
}
void _registerFirstTap(_TapTracker tracker) {
this._startDoubleTapTimer();
GestureBinding.instance.gestureArena.hold(tracker.pointer);
this._freezeTracker(tracker);
this._trackers.Remove(tracker.pointer);
this._clearTrackers();
this._firstTap = tracker;
}
void _registerSecondTap(_TapTracker tracker) {
this._firstTap.entry.resolve(GestureDisposition.accepted);
tracker.entry.resolve(GestureDisposition.accepted);
this._freezeTracker(tracker);
this._trackers.Remove(tracker.pointer);
if (this.onDoubleTap != null) {
this.invokeCallback<object>("onDoubleTap", () => {
this.onDoubleTap();
return null;
});
}
this._reset();
}
void _clearTrackers() {
this._trackers.Values.ToList().Each(this._reject);
D.assert(this._trackers.isEmpty());
}
void _freezeTracker(_TapTracker tracker) {
tracker.stopTrackingPointer(this._handleEvent);
}
void _startDoubleTapTimer() {
this._doubleTapTimer =
this._doubleTapTimer
?? Window.instance.run(Constants.kDoubleTapTimeout, this._reset);
}
void _stopDoubleTapTimer() {
if (this._doubleTapTimer != null) {
this._doubleTapTimer.cancel();
this._doubleTapTimer = null;
}
}
public override string debugDescription {
get { return "double tap"; }
}
}
}