谈谈addSubview和insertSubview

子视图是以栈的方式存放的,也就是说有层次的存放

addSubview:

addsubview时都是在最上面面添加

eg: <pre> UIView*v1 = [UIViewnew];

v1.frame= CGRectMake(100,100,100,60);

v1.backgroundColor= [UIColorredColor];UIView*v2 = [UIViewnew];

v2.backgroundColor= [UIColorpurpleColor];

v2.frame= CGRectMake(80,120,100,60);

[self.viewaddSubview:v1];

[self.viewaddSubview:v2]; </pre> 看到如下效果

pic1

insertSubview

insertSubView可以控制将view添加到指定的层

eg: <pre> UIView*v1 = [UIViewnew];

v1.frame= CGRectMake(100,100,100,60);

v1.backgroundColor= [UIColorredColor];UIView*v2 = [UIViewnew];

v2.backgroundColor= [UIColorpurpleColor];

v2.frame= CGRectMake(80,120,100,60);

[self.viewaddSubview:v1];

[self.viewaddSubview:v2];UIView*v3 = [UIViewnew];

v3.backgroundColor= [UIColoryellowColor];

v3.frame= CGRectMake(60,140,160,60);

[self.viewinsertSubview:v3 atIndex:3]; </pre>

pic2

可以看到v3在v1跟v2之间，按照我们的打算，atIndex:3 应该是在第四层，而现在感觉不像，我们可以打印一下看下究竟： <pre> NSLog(@"%@",self.view.subviews); </pre> 打印如下： <pre>

( "<_UILayoutGuide: 0x7f8893602e80; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x60800003e220>>", "<_UILayoutGuide: 0x7f8893609080; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x60800003e080>>", "<UIView: 0x7f8893406ab0; frame = (100 100; 100 60); layer = <CALayer: 0x60000003de40>>", "<UIView: 0x7f8893407270; frame = (60 140; 160 60); layer = <CALayer: 0x60000003dc00>>", "<UIView: 0x7f8893407c60; frame = (80 120; 100 60); layer = <CALayer: 0x60000003de60>>" ) </pre> 可以看到v1之前，也就是self.view有两层，v1 index就是2， v2的为4，v3 插在 index:3 ，所以在v1跟v2之间。

可以看到：

<pre>[self.view addSubView:xx.view] </code>其实就等于<code>[self.view insertSubView:xx.view atIndex:[self.view.subViews count]];</pre>

即在最顶层添加view。