virtual public Gesture UpdateGestureFromTouches(NSSet touches, TouchEventType touchType)
{
if (touches.Count() == 0)
{
// No touches, do nothing
return(null);
}
// Update the set of current touches
switch (touchType)
{
case TouchEventType.TouchBegan:
case TouchEventType.TouchMoved:
var touchesUnion = currentTouches.Union(touches);
var touchesArray = new UITouch[touchesUnion.Count()];
int i = 0;
foreach (UITouch touch in touchesUnion)
{
touchesArray[i] = touch;
i++;
}
currentTouches = new NSSet(touchesArray);
break;
case TouchEventType.TouchCanceled:
case TouchEventType.TouchEnded:
var notInTouches = NSPredicate.FromExpression(new NSPredicateEvaluator((evaluatedObject, bindings) => !touches.Contains(evaluatedObject)));
currentTouches = currentTouches.FilterUsingPredicate(notInTouches);
break;
}
var expectedTouchCount = (this is SingleFingerGesture) ? 1 : 2;
if (currentTouches.Count() == expectedTouchCount)
{
this.UpdateGesture(null);
return(this);
}
else
{
this.FinishGesture();
this.refreshTimer?.Dispose();
// Erase reference to timer in case callback fires one last time
this.refreshTimer = null;
// Switch to two-finger gesture if was single-finger. If was two-finger, return null
return((this is SingleFingerGesture)
? Gesture.StartGestureFromTouches(currentTouches, this.SceneView, LastUsedObject, manager)
: null);
}
}