objective-c - 检测平移手势结束

Question

我有一个 View ，我将 UIPanGestureRecogniser 应用于该 View :

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAnim:)];
[sliderView addGestureRecognizer:panGesture];
[panGesture release];

我可以很好地检测和处理手势。但是，我希望在手势结束后启动另一个方法。

我知道有两种方法可以进行这种检测。 touchesEnded 和 touchesCancelled 但是，我发现 touchesCancelled 一旦触摸变成手势即被调用，即我移动手指足以保证手势调用和 touchesEnded 很少(如果有的话)被调用。

我希望能够向左/向右平移，然后在手势结束时启动另一个函数调用。我该怎么做？

Answer 1

可以通过使用 UIGestureRecognizerStateEnded 检查其状态来检测平移手势结束事件。

检查下面的代码。

-(void) panAnim:(UIPanGestureRecognizer*) gestureRecognizer
{
   if(gestureRecognizer.state == UIGestureRecognizerStateEnded)
   {
      //All fingers are lifted.
   }
}

来自 Apple 文档

A panning gesture is continuous. Itbegins (UIGestureRecognizerStateBegan)when the minimum number of fingersallowed (minimumNumberOfTouches) hasmoved enough to be considered a pan.It changes(UIGestureRecognizerStateChanged) whena finger moves while at least theminimum number of fingers are presseddown. It ends(UIGestureRecognizerStateEnded) whenall fingers are lifted.

Read more about UIPanGestureRecognizer