如何檢測同時手勢的結束？ （iOS）

Question

在我的應用程序中，我同時使用UIPinchGestureRecognizer，UIRotationGestureRecognizer和UIPanGestureRecognizer來縮放，旋轉和移動圖像。

方法gestureRecognizer：shouldRecognizeSimultaneouslyWithGestureRecognizer：總是返回YES，並且圖像處理效果很好，但是...如何檢測所有同時手勢的結束，以便我可以重置圖像？

Answer 1

如何處理當前正在處理的手勢等簡單解決方案，並在所有手勢都結束時執行操作？

.h文件中：

int handledGesturesCount; 

.m文件：

- (id)init { 
    (...) 
    handledGesturesCount = 0; 
} 

// gesture handlers - the code for -pinch: repeats for -pan: and -rotate: 
- (void)pinch:(UIPinchGestureRecognizer *)recognizer { 
    if (recognizer.state == UIGestureRecognizerStateBegan) { 
     handledGesturesCount += 1; 
    } else if (recognizer.state == UIGestureRecognizerStateEnded || 
       recognizer.state == UIGestureRecognizerStateCancelled || 
       recognizer.state == UIGestureRecognizerStateFailed) 
    { 
     handledGesturesCount -= 1; 
     if (handledGesturesCount == 0) { 
      [self resetImage]; 
     } 
    } 
} 

- (void)pan:(UIPanGestureRecognizer *)recognizer { 
    if (recognizer.state == UIGestureRecognizerStateBegan) { 
     handledGesturesCount += 1; 
    } else if (recognizer.state == UIGestureRecognizerStateEnded || 
       recognizer.state == UIGestureRecognizerStateCancelled || 
       recognizer.state == UIGestureRecognizerStateFailed) 
    { 
     handledGesturesCount -= 1; 
     if (handledGesturesCount == 0) { 
      [self resetImage]; 
     } 
    } 
} 

- (void)rotate:(UIRotationGestureRecognizer *)recognizer { 
    if (recognizer.state == UIGestureRecognizerStateBegan) { 
     handledGesturesCount += 1; 
    } else if (recognizer.state == UIGestureRecognizerStateEnded || 
       recognizer.state == UIGestureRecognizerStateCancelled || 
       recognizer.state == UIGestureRecognizerStateFailed) 
    { 
     handledGesturesCount -= 1; 
     if (handledGesturesCount == 0) { 
      [self resetImage]; 
     } 
    } 
}