視圖控制器不是從應用程序委託呈現

Question

我試圖加載的viewController如果沒有登錄賬戶然而，它給了我這個錯誤Warning: Attempt to present <DefaultViewController: 0xb96cac0> on <MainViewController: 0xb95c320> whose view is not in the window hierarchy! 這裏是我使用的是現在的代碼：

BOOL returnAllOff = [[User data] returnAllOff]; 

if (returnAllOff) { 
    DefaultViewController *viewController =[[DefaultViewController alloc] 
    init]; 
    UIViewController *presentingController = [[[[UIApplication sharedApplication] delegate] window] rootViewController]; 
    [presentingController presentViewController:viewController animated:YES completion:nil]; 

} 

Answer 1

其實這是加載從AppDelegate中一個視圖控制器的正確方式..

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

    DefaultViewController *viewController = [[DefaultViewController alloc] initWithNibName:@"DefaultViewController" bundle:nil]; 
    self.window.rootViewController = viewController; 
    [self.window makeKeyAndVisible]; 

Answer 2

通過的appdelegate進口DefaultViewController試試這一個。

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
DefaultViewController *viewController = [[DefaultViewController alloc] init]; 
self.window.rootViewController = viewController; 
[self.window makeKeyAndVisible];