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

问题

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

回答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!

回答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

来源：https://stackoverflow.com/questions/8089287/in-ios-4-x-or-lower-viewdidappear-method-is-not-getting-called-while-adding-sub

标签

ios4

delegates

uiviewcontroller

ios5

viewwillappear