navigation items disappearing from UINavigationBar

Question

Hi

I am adding a custom background image to my navigation bar by creating an image view and doing a [navigationController.navigationBar addSubview:imageView].

The background comes in fine. But as soon as I do this, my other navigation items start behaving in a strange manner. Sometimes the navigationItem.title appears, the back button disappears. And this is totally random. Any idea what could be causing this?

Thanks.

Answer 1

When in the view setup process are you adding your subview? You may be doing it after your other nav items have been added, and so it's covering them. Try either adding it in your -loadView method, or waiting until -viewWillAppear:, and using -sendSubviewToBack: after adding it.

Answer 2

Thanks a lot. I set the imageView to index 0 and that solved the problem.

Answer 3

Just as an additional thought, I managed to achieve a completely customized navigation bar by overriding drawRect: to have it display a background image. From there, it was easy to set the leftBarButtonItem, rightBarButtonItem, and titleView properties of my navigation controller's navigationItem property to achieve custom buttons and titles. This works with the built-in navigation controller/navigation bar/navigation item logic, so there's no risk of things (like bar buttons) being hidden or obscured.

In a UINavigationBar category:

- ( void )drawRect:( CGRect )rect
{
    [ [ UIImage imageNamed:@"background-image.png" ] drawInRect:CGRectMake( 0, 0, 
      self.frame.size.width, self.frame.size.height ) ];
}

Right before calling pushViewController:animated:, do something like this:

UIButton * leftButton = [ UIButton buttonWithType:UIButtonTypeCustom ];
leftButton.frame = CGRectMake( 0.0, 0.0, 65.0, 32.0 );
[ leftButton setImage:[ UIImage imageNamed:@"left.png" ] forState:UIControlStateNormal ];
[ leftButton addTarget:self action:@selector( leftAction ) forControlEvents:UIControlEventTouchUpInside ];

UIButton * rightButton = [ UIButton buttonWithType:UIButtonTypeCustom ];
rightButton.frame = CGRectMake( 0.0, 0.0, 65.0, 32.0 );
[ rightButton setImage:[ UIImage imageNamed:@"right.png" ] forState:UIControlStateNormal ];
[ rightButton addTarget:self action:@selector( rightAction ) forControlEvents:UIControlEventTouchUpInside ];

UIImageView * titleView = [ [ UIImageView alloc ] initWithImage:[ UIImage imageNamed:@"title.png" ] ];

UIBarButtonItem * leftBarButtonItem = [ [ UIBarButtonItem alloc ] initWithCustomView :leftButton ];
UIBarButtonItem * rightBarButtonItem = [ [ UIBarButtonItem alloc ] initWithCustomView:rightButton ];

nextController.navigationItem.leftBarButtonItem = leftButtonItem;
nextController.navigationItem.rightBarButtonItem = rightButtonItem;
nextController.navigationItem.titleView = titleView;

It's a little busy perhaps, but you could abstract away all this code into a method (or series thereof) somewhere else. This approach tends to work well if you want to completely override any of the styling that occurs in your navigation bar.

Hope this helps!