我可以通过其图层为UIScrollView contentOffset属性设置动画吗？ [英] Can I animate the UIScrollView contentOffset property via its layer?

问题描述

我想用CGPathRef缩放和滚动UIScrollView。因此，我假设我必须为UIScrollView的图层属性设置动画？但是我会为哪个属性设置动画会使它等同于执行UIView动画并设置其contentOffset属性和zoomScale？

I want to zoom and scroll a UIScrollView with a CGPathRef. Because of that I assume I have to animate the UIScrollView's layer property? But which property would I animate that would make it equivalent to doing a UIView animation and setting its contentOffset property and zoomScale ?

这些不是CALayer的属性。

These are not properties of a CALayer.

关于如何处理这个问题的任何想法？再次，只是想将scrollview移动到某个contentOffset和zoomScale，但不一定是从A点到B点的线性移动，分别是缩放A到缩放B.

Any ideas as to how I would approach this? Again, just want to move the scrollview to a certain contentOffset and zoomScale, but not necessarily linearly from point A to point B, zoom A to zoom B, respectively.

I我正在考虑使用CGPathRef进行CAKeyFrameAnimation，但我不知道要设置动画的属性。

I was thinking a CAKeyFrameAnimation with a CGPathRef, but I don't know which properties to animate.

推荐答案

你必须为<动画<动画 bounds 属性。实际上，这就是 contentOffset 属性在幕后使用的内容。

You have to animate the bounds property. In fact, that's what the contentOffset property uses behind the scenes.

示例：

CGRect bounds = scrollView.bounds;

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"bounds"];
animation.duration = 1.0;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

animation.fromValue = [NSValue valueWithCGRect:bounds];

bounds.origin.x += 200;

animation.toValue = [NSValue valueWithCGRect:bounds];

[scrollView.layer addAnimation:animation forKey:@"bounds"];

scrollView.bounds = bounds;

如果您感到好奇，我以前获取此信息的方式如下：

If you're curious, the way I used to get this information is the following:

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.5];

[scrollView setContentOffset:CGPointMake(200, 0) animated:NO];

[UIView commitAnimations];

NSLog(@"%@",scrollView);

NSLog 调用将输出：

<UIScrollView: 0x860ba20; frame = (-65.5 0; 451 367); clipsToBounds = YES; autoresize = W+RM+TM+H; animations = { bounds=<CABasicAnimation: 0xec1e7c0>; }; layer = <CALayer: 0x860bbc0>; contentOffset: {246, 0}>

动画片段将列出所有活动动画，在这种情况下 {bounds =< CABasicAnimation：0xec1e7c0> ;; } 。

The animations snippet will list all the active animations, in this case { bounds=<CABasicAnimation: 0xec1e7c0>; }.

希望这会有所帮助。

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