How to tell when back button is pressed in a UINavigationControllerStack

6
votes

Is it possible to check when the back button is pressed in a UINavigationController stack? I've tried adding a action and target to self.navigationItem.backBarButtonItem to no avail.

Anyone have any solutions?

2
iphoneobjective-cuinavigationcontroller
When you change the backBarButtonItem, make sure you are changing it on the controller that you are going back /to/, not the one that was just pushed. Also, you can only set a custom title or a custom view. If you set a custom image, it has no effect. Finally, you can use Noah's suggestion below, but make yourself the delegate of the navigation controller itself, and respond to the didPopViewController: family of methods. – Jason Coco
UINavigationControllerDelegate doesn't have will/didPopViewController methods, only will/didShowViewController. – dstnbrkr

2 Answers

0
votes

You can try my way:

Write in your ViewController:

UIBarButtonItem *backBt = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"imageNameOfBackButton"] style:UIBarButtonItemStyleBordered target:self action:@selector(backBt_touch:)];
self.navigationItem.leftBarButtonItem = backBt;

And action method:

- (void)backBt_touch:(id)sender {
  [self.navigationController popViewControllerAnimated:YES];
}

You have to take a photo of back button you want.

Animation of hiding back button when viewController is popped is not the same animation of iOS!

P/s: enter image description here I've get it from simulator. Hope it useful! :)

-1
votes

One way to get at this would be to override viewWillDisappear in the UIViewController that is visible when the back button is pressed:

- (void)viewWillDisappear:(BOOL)animated {
    if (self.isMovingFromParentViewController) {
        // handle back button press
    }
}

Obviously this doesn't directly intercept the press on the back button itself, but it gives you a chance to perform logic at that time.