iphone connecting code to the 'back' button

Is there a way to connect code to a view's 'back' button that is part of a navigation controller? That back button is automatically coded in by the nature of it being a navigation controller so I am not sure how I can connect code to it.

(I know this sho开发者_运维知识库uld be really easy but I can't seem to find it in the documentation on navigation controller.)

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viewWillDisappear is where you would typically add code to execute when the back button is pressed

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In reality you should not have a code that needs to be executed when Back button is pressed. What exactly you're trying to achieve?

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You could check if the controller was popped in viewWillDisapper, like in this example:

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    if ([self.navigationController.viewControllers indexOfObject:self]==NSNotFound) {
        // back button was pressed.  We know this is true because self is no longer
        // in the navigation stack.
        NSLog(@"Article done");
    }
}