删除所有子视图？ [英] Remove all subviews?

问题描述

当我的应用程序返回其根视图控制器时，在 viewDidAppear：方法中，我需要删除所有子视图。

When my app gets back to its root view controller, in the viewDidAppear: method I need to remove all subviews.

我该怎么做？

推荐答案

编辑：感谢 cocoafan ：这种情况因 NSView 和<$ c这一事实而变得混乱$ c> UIView 以不同方式处理事物。对于 NSView （仅限桌面Mac开发），您只需使用以下内容：

With thanks to cocoafan: This situation is muddled up by the fact that NSView and UIView handle things differently. For NSView (desktop Mac development only), you can simply use the following:

[someNSView setSubviews:[NSArray array]];

对于 UIView （仅限iOS开发），您可以安全地使用 makeObjectsPerformSelector：，因为子视图属性将返回数组的副本子视图：

For UIView (iOS development only), you can safely use makeObjectsPerformSelector: because the subviews property will return a copy of the array of subviews:

[[someUIView subviews]
 makeObjectsPerformSelector:@selector(removeFromSuperview)];

感谢 Tommy 指出 makeObjectsPerformSelector：似乎在枚举时修改子视图数组（适用于 NSView ，但不适用于 UIView ）。

Thank you to Tommy for pointing out that makeObjectsPerformSelector: appears to modify the subviews array while it is being enumerated (which it does for NSView, but not for UIView).

有关详细信息，请参阅此SO问题 。

Please see this SO question for more details.

注意：使用这两种方法中的任何一种都会删除主视图中包含的每个视图并释放它们 ，如果他们没有留在别处。来自Apple的文档 removeFromSuperview ：

Note: Using either of these two methods will remove every view that your main view contains and release them, if they are not retained elsewhere. From Apple's documentation on removeFromSuperview:

如果接收方的superview不是nil，则此方法释放接收方。如果您打算重用该视图，请务必在调用此方法之前保留它，并确保在完成该操作后或在将其添加到另一个视图层次结构后适当地释放它。

If the receiver’s superview is not nil, this method releases the receiver. If you plan to reuse the view, be sure to retain it before calling this method and be sure to release it as appropriate when you are done with it or after adding it to another view hierarchy.

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