Question

I had this block of code and it worked on iPhone 4S and below. Now with iPhone 5s 4 inch screen it throws an error. I can get around it by commenting out [appDel.navController.view removeFromSuperview]; but I dont think that is the proper way. I dont think this is either so if someone can shed a little light on this that would be great.

Thanks

Code:

[appDel.tabController setSelectedIndex:0];
[appDel.window addSubview:appDel.tabController.view];
[appDel.window bringSubviewToFront:appDel.navController.view];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.6];
[UIView setAnimationDelegate:self];

[UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:appDel.navController.view.superview cache:NO];
[appDel.navController.view removeFromSuperview];

Answer 1

When you are referring to a some object via multiple accessors, e.g. “appDel.navController.view” (I’m trying to think of the formal Objective C name for this, maybe somebody looking at my answer down the road could remind me), it’s very likely that you can get burned by a result not being what you would expect it to be.

In my own code, I try to do as much error checking as possible.

The code below might help you to isolate the issue. In a practical sense, you don’t need so many lines of code, but this might help you to get the idea of what might be going wrong here.

if(appDel)
{
    if(appDel.navController)
    {
        if(appDel.navController.view)
        {
            [appDel.navController.view removeFromSuperview];
        } else {
            NSLog( @"the view of navController is NULL" );
        }
    } else {
        NSLog( @"navController is NULL" );
    }
} else {
    NSLog( @"appDel is NULL" );
}