Disable navigation bar’s back button

I was struggling with the same issue. None of the above solutions worked for me pretty nicely, that is why I decided to do a little investigation and find out how this works.

This is what I discovered:

• When you set the contentSizeForViewInPopover in your view controller it won't be changed by the popover itself - even though popover size may change while navigating to different controller.
• When the size of the popover will change while navigating to different controller, while going back, the size of the popover does not restore
• Changing size of the popover in viewWillAppear gives very strange animation (when let's say you popController inside the popover) - I'd not recommend it
• For me setting the hardcoded size inside the controller would not work at all - my controllers have to be sometimes big sometimes small - controller that will present them have the idea about the size though

A solution for all that pain is as follows:

You have to reset the size of currentSetSizeForPopover in viewDidAppear. But you have to be careful, when you will set the same size as was already set in field currentSetSizeForPopover then the popover will not change the size. For this to happen, you can firstly set the fake size (which will be different than one which was set before) followed by setting the proper size. This solution will work even if your controller is nested inside the navigation controller and popover will change its size accordingly when you will navigate back between the controllers.

You could easily create category on UIViewController with the following helper method that would do the trick with setting the size:

- (void) forcePopoverSize {
    CGSize currentSetSizeForPopover = self.contentSizeForViewInPopover;
    CGSize fakeMomentarySize = CGSizeMake(currentSetSizeForPopover.width - 1.0f, currentSetSizeForPopover.height - 1.0f);
    self.contentSizeForViewInPopover = fakeMomentarySize;
    self.contentSizeForViewInPopover = currentSetSizeForPopover;
}

Then just invoke it in -viewDidAppear of desired controller.

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];
}