How to add view in UIWindow?

Question

I wanted to add a view in UIWindow with following code:

 AppDelegate *delegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
 UIWindo         


        

Answer 1

Your windows needs to have a root view controller.

AppDelegate *delegate = (AppDelegate *)[UIApplication sharedApplication].delegate;

UIWindow *window = delegate.window;
UIViewController *controller = [[UIViewController alloc] init]; 
window.rootViewController = controller;
UIView *aView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
aView.backgroundColor = [UIColor blackColor];
[controller.view addSubview:aView];