子视图出现在父视图 layer.border 下? [英] Subview appears underneath superviews layer.border?

问题描述

我有一个 UIView，我用以下方式定义它的边框:

I have a UIView in which I define it's border in the following manner:

self.layer.borderColor = [UIColor blackColor].CGColor;
self.layer.borderWidth = 3;

我将一个子视图附加到这个 UIView，当我将子视图移到边框上时，它会移到它的下方.这是预期的行为吗?有没有办法让子视图在它上面?

I attach a subview to this UIView, and when I move the subview over the border, it goes underneath it. Is this the intended behavior? Is there anyway to make the subview go on top of it?

推荐答案

根据Apple 规范:它被合成在接收者的内容和子层之上.

因此，边框将始终高于所有子视图，即使您将子视图放在前面等等.

So, the border will always be above of all your subviews, even if you bring your subview to the front and so on.

所以我制作了一个背景视图来伪造边框.

So I make a background view to fake the border.

例如:

UIView *backgroundView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
backgroundView.backgroundColor = [UIColor blackColor];
backgroundView.clipsToBounds = NO;

UIView *bView = [[UIView alloc] initWithFrame:CGRectInset(backgroundView.bounds, 3, 3)];
bView.backgroundColor = [UIColor redColor];

UIView *cView = [[UIView alloc] initWithFrame:CGRectMake(-50, -50, 100, 100)];
cView.backgroundColor = [UIColor yellowColor];
[bView addSubview:cView];

[backgroundView addSubview:bView];

[self.window addSubview:backgroundView];

和效果:

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