代码不在窗口层次结构根视图中[重复]

Question

我在尝试链接我的 UIViewController 时遇到问题，但我得到了最后一个错误。

Attempt to present ViewController whose view is not in the window hierarchy

这是我的代码：

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSString *title = [alertView buttonTitleAtIndex:buttonIndex];

    if([title isEqualToString:@"Wokay"])
    {
        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
        UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"Vibes"];
        [self.window.rootViewController presentViewController:vc animated:YES completion:nil];

    }
}

代码错误：

Warning: Attempt to present <ViewController: 0x110634bc0> on <Login: 0x10951e7f0> whose view is not in the window hierarchy!

Answer 1

您的UIViewController(Login) 似乎不在窗口层次结构中。

您可能会将您的LoginViewController 添加为 UIWindow 中的子视图。 如果是这样，请将其设置为UIWindow 的rootViewController

AppDelegate.m

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

    //Other code parts

    [self.window setRootViewController:loginViewController];
    return YES;
}

或

如果您将 LoginViewController 的视图添加为任何 UIViewController 中的子视图（例如 FirstViewController），请改为显示它

在您的 FirstViewController.m 中，

-(void)viewDidLoad{
    [super viewDidLoad];


    LoginViewController *loginViewController ;//Instantiate LoginViewController here
    [self presentViewController:loginViewController animated:NO completion:Nil];
}