automatic-ref-counting - Release retained property pointing at self.view

Question

In an instance of an UIViewController with ARC best practice would be to "release" any retained subviews of the main view (e.g. self.myOutlet = nil) in - viewDidUnload, and my guess is self.view = nil isn't strictly necessary at this point.

What to do if an additional retained property is defined and assigned as...

self.anotherProperty = self.view;

or

_anotherProperty = self.view; // assuming "_anotherProperty" is the ivar

... is self.anotherProperty = nil necessary then?

Answer 1

viewDidUnload（我假设我们正在谈论在 iOS 6 之前的版本上运行时，因为在 iOS 6 中不再卸载视图，因此不再viewDidUnload调用）是“必要的”；这只是卸载东西的可选机会。

但是如果你想按照 的约定正确卸载东西viewDidUnload，你应该 nil 你的财产吗？是的。1）如果没有，你的属性仍然会保留视图对象，防止它被释放，这是卸载视图的点。2) 视图已经被卸载，也self.view就是设置为nil，当我们决定加载视图时，会被设置为新加载的视图。如果您希望您的属性始终指向self.view，那么您需要效仿并在卸载时将其设置为 nil 并将其设置为viewDidLoad.