何时释放从超级视图中删除的 UIView
我正在创建一个加载屏幕 UIView，它被添加到子视图中，同时从某个 URL 解析一些 XML。返回 XML 后，加载屏幕将从其超级视图中删除。
我的问题是我应该如何释放这个对象？
在下面的代码中，您会看到我将removeFromSuperview发送到loadingScreen，但我仍然拥有这个对象的所有权对象除非我释放它。但是，如果我释放它，viewdidUnload 和 dealloc 中将没有任何内容可以释放。
- (void)loadView {
...
loadingScreen = [[LoadingScreen alloc] initWithFrame: self.view.frame];
[self.view addSubview:loadingScreen]; //retain count = 2
}
-(void)doneParsing {
...
[loadingScreen removeFromSuperview]; //retain count = 1
[loadingScreen release]; //should i release the loading screen here?
}
- (void)viewDidUnload {
[loadingScreen release]; //if viewDidUnload is called AFTER doneParsing, this
//will cause an exception, but the app might crash before
//doneParsing is called, so i need something here
}
- (void)dealloc {
[loadingScreen release]; //if i've already released the object, i can't release here
}
I am creating a loading screen UIView which is added to a subview while some XML is parsed from some URL. Once the XML is returned, the loading screen is removed from its superview.
The question I have is how should I release this object?
In the code below, you'll see that I send removeFromSuperview to the loadingScreen, but I still have ownership of this object unless I release it. But, if I release it, there'll be nothing there to release in viewdidUnload and dealloc.
- (void)loadView {
...
loadingScreen = [[LoadingScreen alloc] initWithFrame: self.view.frame];
[self.view addSubview:loadingScreen]; //retain count = 2
}
-(void)doneParsing {
...
[loadingScreen removeFromSuperview]; //retain count = 1
[loadingScreen release]; //should i release the loading screen here?
}
- (void)viewDidUnload {
[loadingScreen release]; //if viewDidUnload is called AFTER doneParsing, this
//will cause an exception, but the app might crash before
//doneParsing is called, so i need something here
}
- (void)dealloc {
[loadingScreen release]; //if i've already released the object, i can't release here
}
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当你释放loadingScreen时，将其重置为nil值。
[nil release] 不会发生任何事情。
When you release loadingScreen, reset it to a nil value.
[nil release] won't happen anything.