UIPanGestureRecognizer 和 UIPinchGestureRecogizer 用于放大和移动反弹-拉回动画

Posted 2023-03-16

【中文标题】UIPanGestureRecognizer 和 UIPinchGestureRecogizer 用于放大和移动反弹-拉回动画

【英文标题】：UIPanGestureRecognizer and UIPinchGestureRecogizer for zoom in AND move with bounce-pull back animation

【发布时间】：2014-06-25 11:57:59

【问题描述】：

我在 UIView 中有 UIImageView。 请假设用户只能放大（不在此代码中）。 如果 uiimage 比 UIView 大，我需要拉回 uiimage 的动画，就像在 facebook 应用程序中一样。

意思是，如果用户将 UIImageView 向上移动..当他抬起手指时，UIImageView 将被拉回以覆盖底部的空白空间。

我试着玩它，但是..没有运气。 提前致谢

-(void)pinchGestureDetected:(UIPinchGestureRecognizer *)recognizer


    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    

        CGFloat scale = [recognizer scale];



        [recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, scale, scale)];

        [recognizer setScale:1.0];
    


   
- (void)panGestureDetected:(UIPanGestureRecognizer *)recognizer

    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    
        CGPoint translation = [recognizer translationInView:recognizer.view];
        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
        [recognizer setTranslation:CGPointZero inView:recognizer.view];
    



- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer

    return ![gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]];

【参考方案1】：

如果您的图像大于其容器，则应该可以使用：

- (void)panGestureDetected:(UIPanGestureRecognizer *)recognizer

    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    
        CGPoint translation = [recognizer translationInView:recognizer.view];
        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
        [recognizer setTranslation:CGPointZero inView:recognizer.view];
    
    else if(state==UIGestureRecognizerStateEnded)
        UIView *imageView = recognizer.view;
        UIView *container = imageView.superview;

        CGFloat targetX = CGRectGetMinX(imageView.frame);
        CGFloat targetY = CGRectGetMinY(imageView.frame);


        if(targetX>0)
            targetX = 0;
        else if(CGRectGetMaxX(imageView.frame)<CGRectGetWidth(container.bounds))
            targetX = CGRectGetWidth(container.bounds)-CGRectGetWidth(imageView.frame);
        

        if(targetY>0)
            targetY = 0;
        else if(CGRectGetMaxY(imageView.frame)<CGRectGetHeight(container.bounds))
            targetY = CGRectGetHeight(container.bounds)-CGRectGetHeight(imageView.frame);
        

        [UIView animateWithDuration:0.3 animations:^
            imageView.frame = CGRectMake(targetX, targetY, CGRectGetWidth(imageView.frame), CGRectGetHeight(imageView.frame));
        ];
    

【讨论】：

感谢您的帮助。我测试你的代码。放大后，我移动了 uiimageview，但现在不能移动太多，也不能移动到边框。它只停留在中心区域。您的代码在放大后考虑 uiimageview 的新大小？

显然不是 ;) 所以尝试将 viewSize.width 和 viewSize.height 与您当前的 scaleFactor 相乘

不是最好的，但一个简单的解决方案是在每次更改时将比例存储在变量中。如何将比例分配给 UIImageView？

我更新了我的问题。请检查。这是我的错误。当 UIImageView 小于 superview 时，您的代码很好。但是，我的意思是别的。 UIImageView 比 superview 大。当用户结束移动/平移手势时，会有动画拉回图像以覆盖空白空间（因为 uiimageview 比 superview 更大）。 facebook 应用程序 (ipad) 和其他应用程序具有此回拉动画。对不起，我错了。如果您仍然可以提供帮助，请参阅我更新的问题。谢谢！