Question

我使用下面的代码（如下所示）来实现拖放功能。在几个不同的地方徘徊，过去一直对我很好。

现在我遇到了问题而且不知道为什么。只要按下按钮我的设备（或模拟器）导向肖像，它就可以完美地工作。但是在任何其他三个方向中，当手指拖动视图移动一个方向时，“拖动”视图移动不同的方向。

如下图所示，我记录了每次移动的翻译价值。在原始方向中，当我从屏幕中间向左下角拖动时，翻译的值为：

- ，+

如果我向左旋转，再次执行此操作：

- ， -

再次向左旋转：

+， -

再次向左旋转：

+，+

我完全没有得到这里发生的事情，特别是因为这段代码似乎在其他视图控制器中运行良好。

任何建议都将受到赞赏。

- (void) didMakePanGesture:(UIPanGestureRecognizer *)panGesture
{
    if (panGesture.state == UIGestureRecognizerStateBegan)
    {
        [self setDropTargetsCoordinates];                                                           // saves correct drop target & its coordinates
        dragViewStartLocation = receptiveClassificationImageView.center;                            // save center in case we have to snap back
        receptiveClassificationImageView.transform = CGAffineTransformMakeScale(0.40f, 0.40f);      // make the image smaller for dragging
        receptiveClassificationImageView.layer.cornerRadius = 12.0f;                                // we lose the rounded corners in the scaling; this to fix
    }
    else if (panGesture.state == UIGestureRecognizerStateChanged)
    {
        //
        //   Adjust the location of the dragged view whenever state changes
        //
        CGPoint translation = [panGesture translationInView:nil];
        CGAffineTransform transform = receptiveClassificationImageView.transform;
        transform.tx = translation.x;
        transform.ty = translation.y;
        receptiveClassificationImageView.transform = transform;
        NSLog(@"Translation=%f,%f" translation.x, translation.y);


    }
    else if (panGesture.state == UIGestureRecognizerStateEnded)
    {
        // do stuff when dropped   
    }

Answer 1

以防有人稍后看到此问题，以上代码的以下更改解决了此问题：

if (panGesture.state == UIGestureRecognizerStateBegan)
{
    [self setDropTargetsCoordinates];                                                           // saves correct drop target & its coordinates
    dragViewStartLocation = receptiveClassificationImageView.center;                            // save center in case we have to snap back
    **receptiveClassificationImageView.center = [panGesture locationInView:receptiveClassificationImageView.superview]; // re-center the view before scaling**
    receptiveClassificationImageView.transform = CGAffineTransformMakeScale(0.40f, 0.40f);      // make the image smaller for dragging
    receptiveClassificationImageView.layer.cornerRadius = 12.0f;                                // we lose the rounded corners in the scaling; this to fix
}
else if (panGesture.state == UIGestureRecognizerStateChanged)
{
    //
    //   Adjust the location of the dragged view whenever state changes
    //
    CGPoint translation = [panGesture translationInView:**self.view**];
    CGAffineTransform transform = receptiveClassificationImageView.transform;
    transform.tx = translation.x;
    transform.ty = translation.y;
    receptiveClassificationImageView.transform = transform;
}

ios拖动;使用设备旋转删除

1 个答案: