按下UILongPressGestureRecognizer会被调用两次

我正在检测用户是否按下了2秒钟：

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; longPress.minimumPressDuration = 2.0; [self addGestureRecognizer:longPress]; [longPress release]; 

这是我如何处理长按：

 -(void)handleLongPress:(UILongPressGestureRecognizer*)recognizer{ NSLog(@"double oo"); } 

当按下2秒以上时，文本“double oo”会被打印两次。 为什么是这样？ 我该如何解决？

Answer 1

UILongPressGestureRecognizer是一个连续的事件识别器。 你必须看看状态，看看这是事件的开始，中间还是结束，并采取相应的行动。 即你可以在开始之后扔掉所有的事件，或者只根据需要看运动。 从类参考 ：

长按手势是连续的。 当在指定的时间段（minimumPressDuration）按下允许的手指的数量（numberOfTouchesRequired）并且触摸不超过允许的移动范围（allowableMovement）时，手势开始（UIGestureRecognizerStateBegan）。 当手指移动时，手势识别器转换到改变状态，并且当任何手指抬起时手势识别器结束（UIGestureRecognizerStateEnded）。

现在你可以跟踪像这样的状态

 - (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 } } 

Answer 2

要检查UILongPressGestureRecognizer的状态，只需在select器方法中添加一个if语句：

 - (void)handleLongPress:(UILongPressGestureRecognizer *)sender { if (sender.state == UIGestureRecognizerStateEnded) { NSLog(@"Long press Ended"); } else if (sender.state == UIGestureRecognizerStateBegan) { NSLog(@"Long press detected."); } } 

Answer 3

您需要检查正确的状态，因为每个状态都有不同的行为。 最有可能的是你将需要UILestPressRecognizerStateBegan状态与UILongPressGestureRecognizer。

 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; longPress.minimumPressDuration = 1.0; [myView addGestureRecognizer:longPress]; [longPress release]; 

…

 - (void)handleLongPress:(UILongPressGestureRecognizer *)gesture { if(UIGestureRecognizerStateBegan == gesture.state) { // Called on start of gesture, do work here } if(UIGestureRecognizerStateChanged == gesture.state) { // Do repeated work here (repeats continuously) while finger is down } if(UIGestureRecognizerStateEnded == gesture.state) { // Do end work here when finger is lifted } } 

Answer 4

试试这个：

Objective-C的

 - (void)handleLongPress:(UILongPressGestureRecognizer*)sender { if (sender.state == UIGestureRecognizerStateEnded) { NSLog(@"Long press Ended"); } else if (sender.state == UIGestureRecognizerStateBegan) { NSLog(@"Long press detected."); } } 

Swift 2.2：

 func handleLongPress(sender:UILongPressGestureRecognizer) { if (sender.state == UIGestureRecognizerState.Ended) { print("Long press Ended"); } else if (sender.state == UIGestureRecognizerState.Began) { print("Long press detected."); } } 

Answer 5

以下是如何在Swift中处理它：

 func longPress(sender:UILongPressGestureRecognizer!) { if (sender.state == UIGestureRecognizerState.Ended) { println("Long press Ended"); } else if (sender.state == UIGestureRecognizerState.Began) { println("Long press detected."); } } 

Answer 6

Swift 3.0：

 func handleLongPress(sender: UILongPressGestureRecognizer) { if sender.state == .ended { print("Long press Ended") } else if sender.state == .began { print("Long press detected") } 

Answer 7

你的手势处理程序接收每个手势状态的调用。 所以你需要检查每个状态，并把你的代码置于所需的状态。

我们必须更喜欢使用if-else开关的情况：

 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; longPress.minimumPressDuration = 1.0; [myView addGestureRecognizer:longPress]; [longPress release]; 

---

 -(void)handleLongPress:(UILongPressGestureRecognizer *)gesture { switch(gesture.state){ case UIGestureRecognizerStateBegan: NSLog(@"State Began"); break; case UIGestureRecognizerStateChanged: NSLog(@"State changed"); break; case UIGestureRecognizerStateEnded: NSLog(@"State End"); break; default: break; } }