Custom dealloc and ARC (Objective-C)

问题

In my little iPad app I have a "switch language" function that uses an observer. Every view controller registers itself with my observer during its viewDidLoad:.

- (void)viewDidLoad
{
    [super viewDidLoad];
    [observer registerObject:self];
}

When the user hits the "change language" button, the new language is stored in my model and the observer is notified and calls an updateUi: selector on its registered objects.

This works very well, except for when I have view controllers in a TabBarController. This is because when the tab bar loads, it fetches the tab icons from its child controllers without initializing the views, so viewDidLoad: isn't called, so those view controllers don't receive language change notifications. Because of this, I moved my registerObject: calls into the init method.

Back when I used viewDidLoad: to register with my observer, I used viewDidUnload: to unregister. Since I'm now registering in init, it makes a lot of sense to unregister in dealloc.

But here is my problem. When I write:

- (void) dealloc
{
    [observer unregisterObject:self];
    [super dealloc];
}

I get this error:

ARC forbids explicit message send of 'dealloc'

Since I need to call [super dealloc] to ensure superclasses clean up properly, but ARC forbids that, I'm now stuck. Is there another way to get informed when my object is dying?

回答1:

When using ARC, you simply do not call [super dealloc] explicitly - the compiler handles it for you (as described in the Clang LLVM ARC document, chapter 7.1.2):

- (void) dealloc
{
    [observer unregisterObject:self];
    // [super dealloc]; //(provided by the compiler)
}

来源：https://stackoverflow.com/questions/7292119/custom-dealloc-and-arc-objective-c