Question

我有一个UIButton我以编程方式创建。实际上它应该是UIButton，我只需要有可能在图像上方标记一些区域。

所以我需要它的功能 - 移动对象并调整它的大小。为此，我有两种方法：

- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
 UIControl *control = sender;
 UITouch *t = [[event allTouches] anyObject];
 CGPoint pPrev = [t previousLocationInView:control];
 CGPoint p = [t locationInView:control];
 CGPoint center = control.center;
 center.x += p.x - pPrev.x;
 center.y += p.y - pPrev.y;
 control.center = center;
}

- (void)objScale:(UIPinchGestureRecognizer *)recognizer
{
 UIView *pinchView = recognizer.view;
 CGRect bounds = pinchView.bounds;
 CGPoint pinchCenter = [recognizer locationInView:pinchView];
 pinchCenter.x -= CGRectGetMidX(bounds);
 pinchCenter.y -= CGRectGetMidY(bounds);
 CGAffineTransform transform = pinchView.transform;
 transform = CGAffineTransformTranslate(transform, pinchCenter.x, pinchCenter.y);
 CGFloat scale = recognizer.scale;
 transform = CGAffineTransformScale(transform, scale, scale);
 transform = CGAffineTransformTranslate(transform, -pinchCenter.x, -pinchCenter.y);
 pinchView.transform = transform;
 recognizer.scale = 1.0;
}

比例正常。移动看起来没问题，直到我改变对象的大小 - 当我增加对象时，它变得比手指慢，反之亦然 - 如果对象小于原始对象，它比手指移动得快。为什么它会像这样？

Answer 1

我认为你应该在

中获得startPoint和startCenter

 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
 // get startPoint and startCenter here
}

- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
 UIControl *control = sender;
 UITouch *t = [[event allTouches] anyObject];
 CGPoint p = [t locationInView:control];
 startCenter.x += p.x - startPoint.x;
 startCenter.y += p.y - startPoint.y;
 control.center = startCenter;
}

像这样更改你的代码，也许它可行。

您的中心是当前中心，p是当前点，pPrev是前一点。当前中心添加前一点移动大小是错误的。你应该得到相对距离，而不是动态距离。

UIButton - 移动和缩放

1 个答案: