控制器的创建方式 -- 及其导航控制器的管理

 1 self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
 2     
 3     self.window.backgroundColor = [UIColor blueColor];
 4    
 5     UIStoryboard *story = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
 6     
 7 //    SDoneViewController *vc = [story instantiateInitialViewController];
 8     
 9     SDoneViewController *VC1 = [story instantiateViewControllerWithIdentifier:@"two"];
10     
11     self.window.rootViewController = VC1;
12     
13     
14     [self.window makeKeyAndVisible];
15     
16     return YES;

    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    
    self.window.backgroundColor = [UIColor blueColor];

    SDoneViewController *vc = [[SDoneViewController alloc] init];
    
    self.window.rootViewController = vc;
    
    
    [self.window makeKeyAndVisible];
    
    return YES;

elf.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    
    self.window.backgroundColor = [UIColor blueColor];
   
    SDThreeViewController *three = [[SDThreeViewController alloc] initWithNibName:@"three" bundle:nil];
    
    self.window.rootViewController = three;
    
    
    [self.window makeKeyAndVisible];
    
    return YES;