1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 2     // Override point for customization after application launch.
 3     
 4     self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
 5     [self.window makeKeyAndVisible];
 6     
 7     AClassViewController *aVC = [[AClassViewController alloc] init];
 8     self.window.rootViewController = aVC;
 9     
10     return YES;
11 }

1 self.view.backgroundColor = [UIColor lightGrayColor];