iOS 中长按手势回调会被触发过两次

根据苹果的文档，这个手势对应的 action 会被调用两次。

正确的做法是在 action 中判断手势的状态，如下：

-  (void)handleLongPress:(UILongPressGestureRecognizer*)sender {

    if (sender.state == UIGestureRecognizerStateEnded) {

      NSLog(@"UIGestureRecognizerStateEnded");

    //Do Whatever You want on End of Gesture

     }

    else if (sender.state == UIGestureRecognizerStateBegan){

       NSLog(@"UIGestureRecognizerStateBegan.");

   //Do Whatever You want on Began of Gesture

     }

  }

参考

• Handling Long-Press Gestures
• UILongPressGestureRecognizer called twice