back button callback in navigationController in iOS

Question

I have pushed a view onto the navigation controller and when I press the back button it goes to the previous view automatically. I want to do a few things when back button is pressed before popping the view off the stack. Which is the back button callback function?

Answer 1

William Jockusch's answer solve this problem with easy trick.

-(void) viewWillDisappear:(BOOL)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.       }     [super viewWillDisappear:animated]; } 

Answer 2

In my opinion the best solution.

- (void)didMoveToParentViewController:(UIViewController *)parent {     if (![parent isEqual:self.parentViewController]) {          NSLog(@"Back pressed");     } } 

But it only works with iOS5+