CODEWITHSUNDEEP
iphoneobjective-cmemory-managementuiviewdealloc
dianovich
dianovich

Reputation: 2287

When to release a UIView that is removed from superview

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
}

Upvotes: 1

Views: 1187

Answers (1)

AechoLiu
AechoLiu

Reputation: 18428

When you release loadingScreen, reset it to a nil value.

[loadingScreen release];
loadingScreen = nil;

[nil release] won't happen anything.

Upvotes: 2

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