不要使用superview alpha值更新子视图

Question

我的问题是当我将视图作为子视图添加到根视图时。当我更改根视图的alpha值时，同样在子视图中也发生。实际上我不需要在子视图中进行更新。是否有任何解决方案可以做到这一点。

Answer 1

这将仅更改根视图的alpha，而不更改其他视图的alpha

    self.view.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5];

Answer 2

Building on the answer by @shabbirv, one can also use IB's color picker

Answer 3

You'd need to change the structure of your views. Instead of laying your subviews out on the roots view, create a layer ontop of your root view, but still add the subviews to the root. When changing the layer's alpha it won't effect the subviews. Example structure below.

Your current structure:

RootView->Subviews //Changing RootView alpha effects Subviews.

Needed Structure:

RootView->View->Subviews(Still Added to RootView) //Changing alpha of Layer doesn't effect subviews.

Hope this helps.

Answer 4

这也将通过以下方式改变根视图颜色来解决这个问题，这不会影响子视图。

[rootView setBackgroundColor:[[UIColor blackColor] colorWithAlphaComponent:0.7]];