在 iOS 中获取触摸位置时，PAN 手势崩溃

Question

我只是做了一个示例来检查平移手势。

平移手势正在检测并且工作正常。

但是每当我在平移手势中给出第二个点时，就像CGPoint secondPoint = [sender locationOfTouch:1 inView:self.imageView];它崩溃了一样。

控制台正在给出消息

 *** Terminating app due to uncaught exception 'NSRangeException', reason: '-[UIPanGestureRecognizer locationOfTouch:inView:]: index (1) beyond bounds (1).'

当我使用panGestureRecognizer.maximumNumberOfTouches = 1; panGestureRecognizer.minimumNumberOfTouches =1; 它仍然崩溃。

当我使用panGestureRecognizer.maximumNumberOfTouches = 2; panGestureRecognizer.minimumNumberOfTouches = 2; 时，它没有进入

- (void)panGestureHandler:(UIPanGestureRecognizer *)sender method.

谁能指导我哪里出错了。

预先感谢您。希望您的帮助。

我用这种方式尝试过。

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGestureHandler:)];
     panGestureRecognizer.maximumNumberOfTouches = 2;
     [self.imageView addGestureRecognizer:panGestureRecognizer];

}
- (void)panGestureHandler:(UIPanGestureRecognizer *)sender
{
    if ([sender state] == UIGestureRecognizerStateBegan )
    {
        CGPoint firstPoint = [sender locationOfTouch:0 inView:self.imageView];
        CGPoint secondPoint = [sender locationOfTouch:1 inView:self.imageView];
    }
    else if ([sender state] ==UIGestureRecognizerStateEnded ) 
    {
    }

}

Answer 1

尽管设置了最大和最小触摸次数，我也遇到了这个错误。我正在对我的手势识别器进行子类化，并认为它与此有关。我通过在引用它之前简单地检查来解决它numberOfTouches：

if ([gestureRecognizer numberOfTouches] > 0) {
    CGPoint point = [gestureRecognizer locationOfTouch:0 inView:self.superview.window];
}

希望这对某人有帮助！