Sometimes it’s useful to quickly see all the subviews of a UIView.

Perhaps you’re debugging a problem in one of your views or trying to understand the inner workings of one of the built in views.

You can simply iterate over a view’s subviews, but then you won’t see subviews deeper than one level. You need a method that recursively walks the hierarchy.

Luckily Apple has already done this with the recursiveDescription method, part of a UIDebugging category on UIView.

recursiveDescription was recently documented in a tech note titled iOS Debugging Magic.

At the gdb prompt in the Xcode debugger you can say:

(gdb) po [[self view] recursiveDescription]

and instantly see a description of the entire view hierarchy. We used this in our Transparent UIWebViews recipe to figure out the view hierarchy of a UIWebView:

(gdb) po [webView recursiveDescription]
<UIWebView: 0x68220e0; frame = (0 0; 320 460); >
| <UIScrollView: 0x4b2bee0; frame = (0 0; 320 460); >
|    | <UIImageView: 0x4b2dca0; frame = (0 0; 54 54); >
|    | <UIImageView: 0x4b2da20; frame = (0 0; 54 54); >
|    | <UIImageView: 0x4b2d9c0; frame = (0 0; 54 54); >
|    | <UIImageView: 0x4b12030; frame = (0 0; 54 54) >
|    | <UIImageView: 0x4b11fd0; frame = (-14.5 14.5; 30 1); >
|    | <UIImageView: 0x4b11f70; frame = (-14.5 14.5; 30 1); >
|    | <UIImageView: 0x4b11f10; frame = (0 0; 1 30); >
|    | <UIImageView: 0x4b11eb0; frame = (0 0; 1 30); >
|    | <UIImageView: 0x4b11e50; frame = (0 430; 320 30); >
|    | <UIImageView: 0x4b2d0c0; frame = (0 0; 320 30);  >
|    | <UIWebBrowserView: 0x6005800; frame = (0 0; 320 460); >

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