当从层次结构中删除视图时，是否会调用willMoveToSuperview（使用nil）？ [英] Is willMoveToSuperview called (with nil) when removing a view from a hierarchy?

问题描述

如果您在 UIView 子类中实现 willMoveToSuperview ，则会保证被调用（<$ c $在您的视图中调用 removeFromSuperview 时，

$ <$>

$ b newSuperview 参数可以为 nil ，并且称为超看更改，但我不确定是否可以解释这意味着当视图从其超级视图中删除时，即使没有移动到不同的超级视图，它将被调用。

解决方案

每当视图接收到 removeFromSuperview ，并且视图的superview不是nil， [self willMoveToSuperview：nil] 。

If you implement willMoveToSuperview on a UIView subclass, is it guaranteed to be called (with nil) when removeFromSuperview is called on your view?

The docs say that the newSuperview parameter may be nil and that it's called "whenever the superview changes" but I'm not sure if I can interpret this to mean it will be called when the view is removed from its superview even when not being moved to a different superview.

解决方案

Whenever a view receives removeFromSuperview, and the view's superview was not already nil, the view will always do [self willMoveToSuperview:nil].

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