Question

我在激活应用程序时创建了一个文件。在此基础上，该文件的存在会加载不同的视图。

我正在尝试

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

    // Override point for customization after application launch.

    // Add the view controller's view to the window and display.
    if(condition true)
    {
        //[window addSubview:viewController.view];
        [self.window setRootViewController:viewController];
        [window makeKeyAndVisible];
        return YES;
    }else{
        //[window addSubview:signViewController.view];
        [self.window setRootViewController:secondViewController];
        [window makeKeyAndVisible];
        return YES;
    }

   // return YES;
}

我得到的错误是Application windows are expected to have a root view controller at the end of application launch

Answer 1

在使用视频控制器之前，首先应alloc和init。

if(condition true)
{
    //[window addSubview:viewController.view];
    viewController = [[ViewController alloc] init];
    [self.window setRootViewController:viewController];
    [window makeKeyAndVisible];
    return YES;
}else{
    //[window addSubview:signViewController.view];
    secondViewController = [[SecondViewController alloc] init];
    [self.window setRootViewController:secondViewController];
    [window makeKeyAndVisible];
    return YES;
}

Answer 2

写一下

[window makeKeyAndVisible];
    return YES;

其他之后或}之前

Answer 3

检查视图控制器是否有alloc和init。使用 viewController = [[ViewControllerName alloc] init];

我的viewController未分配时出现同样的错误。

应用程序应该添加rootViewController

3 个答案: