如何正确使用UINavigationController

Question

I just recently started programming for iOS/iPhone . I thought I knew what I was doing until XCode5/iOS7 came around. Previously, I created a class derived from UIViewController with a XIB , added a label, and programatically added it to the rootWindow:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    ... // boilerplate code
    MyViewController* myRoot = [[MyViewController alloc]init];
    self.window.rootViewController = myRoot;

To use a navigation bar, I changed the code slightly:

MyViewController* myRoot = [[MyViewController alloc]init];
UINavigationController* navigationController = [[UINavigationController alloc]init];
[navigationController pushViewController:myRoot animated:YES];
self.window.rootViewController = navigationController;

This seemed to work fine. However, on iOS 7 the controls at the top of my custom view controller appear to be behind the navigation bar. Some googling resulted in this link which describes changes in the status bar.

It also seems to indicate that, A) UINavigationController should handle the changes automatically B) "auto layout" should handle the changes automatically,

and that I shouldn't need to worry. However, my sample app above doesn't appear to handle anything automatically.

I also found some other sample code which uses the controller differently: adding the navigation controller's view as a subView to an existing view. This sort of makes sense for adding a navigation controller later on in an app's lifetime, but I am trying to set one up on launch.

Am I using the UINavigationController correctly?

What do I need to consider for iOS7 vs. earlier versions?

How do I configure "Auto Layout" (I don't see this in interface builder anywhere)?

Answer 1

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.navigationController = [[UINavigationController alloc] initWithRootViewController:self.viewController];
    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];
    return YES;
}