我的视图控制器没有出现在屏幕上

Question

我选择选项卡式应用程序模板。然后我添加了CoolViewController，但它没有出现在屏幕上。哪里不对？

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil]; 
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil]; 
self.tabBarController = [[UITabBarController alloc] init]; 
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil]; 
self.window.rootViewController = self.tabBarController; 

CoolViewController *coolVC = [[CoolViewController alloc] init]; 
coolVC.view.frame = CGRectMake(0, 0, 320, 200); 
coolVC.view.backgroundColor = [UIColor blackColor]; 
[self.window addSubview:coolVC.view]; 

[self.window makeKeyAndVisible]; 
return YES; 
} 

@interface CoolViewController : UIViewController 
@end 

Answer 1

您不应该将CoolViewController添加到窗口，而是添加到UITabBarController。

您应该结束了，像这样：（注意：我还没有尝试过）

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil]; 
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil]; 
self.tabBarController = [[UITabBarController alloc] init]; 

CoolViewController *coolVC = [[CoolViewController alloc] init]; 
coolVC.view.frame = CGRectMake(0, 0, 320, 200); 
coolVC.view.backgroundColor = [UIColor blackColor]; 

self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2,coolVC, nil]; 
self.window.rootViewController = self.tabBarController; 




[self.window makeKeyAndVisible]; 
return YES; 
}