In IOS 4.x or lower, viewDidAppear method is not getting called while adding subview to a view, why?

Question

In iOS 4.x or lower, viewDidAppear and viewWillAppear, viewDidDisappear and viewWillDisappear, such ViewController's delegate methods are not getting called. The same methods work fine with the iOS 5.x.

Why? Is it a bug in iOS 4.x or lower. Because in iOS 5.x all those methods gets called in proper manner and sequence.

Thanks in advance, Mrunal

Answer 1

For IOS4.x i use the UINavigationController delegate methods like this:

-(void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if (SYSTEM_VERSION_LESS_THAN(@"5.0")) {
        [activeView viewDidAppear:YES];
    }
}
-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if (SYSTEM_VERSION_LESS_THAN(@"5.0")) {
        [activeView viewWillAppear:YES];
    }
}

I hope this helps!

Answer 2

If your view controller is a child of another view controller, (i.e. it's a UINavigationController inside a UIViewController, or vice versa, etc.), the child's viewDidAppear, viewWillAppear, etc. methods will not get called. The solution is to have the parent call into them like:

-(void)viewWillAppear:(BOOL)animated { 
    [super viewWillAppear:animated];
    [child viewWillAppear:animated];
}

I know this happens through iOS 4.3. In iOS 5 there is a new set of methods specifically for handling these cases: Implementing a Container View Controller