Adding and Removing Subviews

//The first example is adding a subview to your MainWindow nib so that it loads a nib from another view controller.
//The following code goes in the AppDelegate.m under the following method

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // Override point for customization after application launch
	[window addSubview:switchViewController.view]; //replace switchViewController with your own viewController
    [window makeKeyAndVisible];
	
	return YES;
}

//The second example shows how to add subviews to a viewController
//This would go in the view controller you are adding subviews to.
- (void)viewDidLoad {
    [super viewDidLoad];
	
	//In this case, BlueViewController is a viewController that is being called in this viewController (switchViewController)
	BlueViewController *blueController = [[BlueViewController alloc] initWithNibName:@"BlueViewController" bundle:nil];
	self.blueViewController = blueController;
	[self.view insertSubview:blueController.view atIndex:0]; //index 0 determines zindex.
	[blueController release];
}


//This example shows how to remove views (like the one above)
[yellowViewController.view removeFromSuperview];

//You can also check to see if the view of a given viewController is present using the following:
if (self.blueViewController.view.superview == nil) {
	...	
}