objective-c - ONLongPress手势检测两次

Question

在我的长按手势中，我遇到了这样的问题，

*mypressrec = [[UILongPressGestureRecognizer alloc]
                                         initWithTarget:self 
                                         action:@selector(pressdetected:)];
    mypressrec.minimumPressDuration = 3;
    [self addGestureRecognizer:mypressrec];
    [mypressrec release];

我的功能:

    -(void)pressdetected:(UILongPressGestureRecognizer*)recognizer{
     //My code goes here
  a=90;
   NSLog(@"value of my A",a);
}

这里，当我按下超过 3 秒时，我的 A 的值将打印两次。为什么会发生这种情况？

Answer 1

要检查 UILongPressGestureRecognizer 的状态，只需在选择器方法上添加 if 语句:

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