Code to manually create UIWindow, and UIViewController with customized UIView without involving with Interface Builder

gistfile1.txt

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    CGRect screenRect = [UIScreen mainScreen].bounds;
    
    self.window = [[UIWindow alloc] initWithFrame:screenRect];
    GLView *glView = [[GLView alloc] initWithFrame:screenRect];
    
    UIViewController *rootVc = [[UIViewController alloc] init];
    [rootVc.view addSubview:glView];
    
    self.window.rootViewController = rootVc;
    [self.window makeKeyAndVisible];
    
    return YES;
}