UIPanGestureRecognizer 在 iPad 上不起作用？

Posted 2023-03-16

【中文标题】UIPanGestureRecognizer 在 iPad 上不起作用？

【英文标题】：UIPanGestureRecognizer not working on iPad?

【发布时间】：2015-01-06 07:49:32

【问题描述】：

我在下面有一个 UIPanGestureRecognizer 代码：

self.panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panThis:)];
self.panRecognizer.delegate = self;
[self.view addGestureRecognizer:self.panRecognizer];


- (void)panThis:(UIPanGestureRecognizer *)recognizer

    switch (recognizer.state)
    
        case UIGestureRecognizerStateBegan:
        
            CGPoint panStartPoint = [recognizer translationInView:self.view];
            NSLog(@"Pan Began at %@", NSStringFromCGPoint(panStartPoint));
            break;
        
        default:
            break;
    

它可以在 iPhone 上找到，但在 iPad 上，它无法识别平移手势并继续记录

Pan Began at 0, 0
Pan Began at 0, 0
Pan Began at 0, 0

我的代码有什么问题吗？非常感谢

【参考方案1】：

这是我的代码.. 它有效。试一试。

- (void)handlePan:(UIPanGestureRecognizer *)recognizer 

    NSLog(@"handlePan");
    //CGPoint p;
    switch (recognizer.state) 
        case UIGestureRecognizerStateBegan:
NSLog(@"UIGestureRecognizerStateBegan");


            break;

        case UIGestureRecognizerStateEnded:
            // All fingers are lifted.
            break;

        default:
            break;
    

    UIView * inView = recognizer.view;
    CGPoint translation = [recognizer translationInView:self.view];

    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
                                         recognizer.view.center.y + translation.y);

    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];

    ///relative to view.
    CGPoint center = inView.center;
    NSLog(@"handlePan %f %f", center.x, center.y);

【讨论】：

谢谢。我想通了，它应该是velocityInView，而不是UIGestureRecognizerStateBegan状态下的translationInView

"velocityInView" 对我帮助很大。