得到UIView框架的缩放动画 [英] get to an UIView frame a zoom animation

问题描述

我正在尝试添加一个带有过渡样式缩放动画的UIView，如下所示：

I am trying to add one UIView with a transition style zoom animation like this:

     ^
     |
 <---.--->
     |
     v

视图以一个小框架开始（centerParent.x，centerParent.y，20 ，20）然后改为（centerParent.x，centerParent.y，300,300）。

The view start with a little frame (centerParent.x, centerParent.y,20, 20) and then change to (centerParent.x, centerParent.y,300, 300).

但是当我改变帧时，我必须改变它，因为视图的位置（0.0），而不是它的中心点。有谁知道怎么做？

But when I change the frame I have to change it since the postion (0.0) of the view, not for it's center point. Does anyone know how to do it?

谢谢

推荐答案

随着您当前正在使用的方法（不使用转换，只需调整视图大小），您只需重置视图的原点或中心即可。最简单的是中心：

With the methodology you're currently using (not using a transform but simply resizing the view) you just need to reset the origin or center of the view). The easiest is the center:

 view.frame = CGRectMake(0, 0, 20, 20);
    CGPoint center = view.center;
    [UIView animateWithDuration: 1.0f animations:^{
        view.frame = CGRectMake(0, 0, 300, 300);
        view.center = center;
    }];

您还可以通过从x减去1/2大小变化的差异来重置原点和y，但这是更多的数学：

You can also reset the origin by moving subtracting 1/2 the difference of the size change from the x and y, but this is more math:

view.frame = CGRectMake(0, 0, 20, 20);
    CGPoint origin = view.frame.origin.
    [UIView animateWithDuration: 1.0f animations:^{
        origin.x -= (300 - 20) / 2;
        origin.y -= (300 - 20) / 2;
        view.frame = CGRectMake(origin.x, origin.y, 300, 300);
    }];

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