ios - UILongPressGestureRecognizer 不起作用

Question

我在 UIImageView 中添加了 4 个手势识别器，单击、双击和 pin 手势工作正常。但是，长按手势不起作用。这是为什么？

        _imageView.userInteractionEnabled = YES ;

    //single tap
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc ]initWithTarget:self action:@selector(singleTapAction:) ]  ;
    singleTap.numberOfTapsRequired = 1 ;
    singleTap.numberOfTouchesRequired = 1 ;

    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapAction:)] ;
    doubleTap.numberOfTouchesRequired = 1 ;
    doubleTap.numberOfTapsRequired = 2 ;
    [singleTap requireGestureRecognizerToFail:doubleTap] ;

    //pin gesture
    UIPinchGestureRecognizer  *pin = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)] ;

    //long press gesture
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:) ] ;
    [longPress requireGestureRecognizerToFail:singleTap ] ;
    longPress.minimumPressDuration = 1 ;
    longPress.numberOfTouchesRequired = 1 ;
    longPress.numberOfTapsRequired = 1 ;

    [_imageView addGestureRecognizer:longPress] ;
    [_imageView addGestureRecognizer:pin] ;
    [_imageView addGestureRecognizer:singleTap] ;
    [_imageView addGestureRecognizer:doubleTap] ;


- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    return YES;
}

大家好，我加了 shouldRecognizeSimultaneouslyWithGestureRecognizer方法并设置长按 gesutre 委托(delegate)，但这仍然不起作用。

Answer 1

你的错误可能在这里

[longPress requireGestureRecognizerToFail:longPress ] ;

为什么 longPress 要求本身失败？删除它。

您不了解 requireGestureRecognizerToFail 命令。它在手势需要其他未能触发时使用。如果 longPress 未触发，则触发 tapGesture。
在你的情况下捏失败->长按失败->双击失败->单击
同时删除这一行: longPress.numberOfTapsRequired = 1 ;

注释掉您的代码并使用此代码:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.imageView.userInteractionEnabled = YES;
    self.imageView.multipleTouchEnabled = YES;
    UIGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)];

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
    longPress.minimumPressDuration = 1 ;
    longPress.numberOfTouchesRequired = 1 ;
    [longPress requireGestureRecognizerToFail:pinchGesture];

    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
    doubleTap.numberOfTouchesRequired = 1;
    doubleTap.numberOfTapsRequired = 2;
    [doubleTap requireGestureRecognizerToFail:longPress];

    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    singleTap.numberOfTouchesRequired = 1;
    singleTap.numberOfTapsRequired = 1;
    [singleTap requireGestureRecognizerToFail:doubleTap];

    [self.imageView addGestureRecognizer:pinchGesture];
    [self.imageView addGestureRecognizer:longPress];
    [self.imageView addGestureRecognizer:doubleTap];
    [self.imageView addGestureRecognizer:singleTap];

}

- (void)handlePinchGesture:(UIPinchGestureRecognizer *)gesture{
    NSLog(@"Pinch");
}


- (void)handleLongPress:(UILongPressGestureRecognizer *)gesture{
    NSLog(@"LongPress");
}

- (void)handleDoubleTap:(UITapGestureRecognizer *)gesture{
    NSLog(@"Double Tap");
}

- (void)handleSingleTap:(UITapGestureRecognizer *)gesture{
    NSLog(@"Single Tap");
}