dismissViewControllerAnimated问题

Question

我的应用的第一个屏幕包含登录屏幕。我正在显示AppDelegate的登录屏幕。 登录屏幕出现，我可以在模拟器中转到下一个屏幕。但它并不适用于设备。

在设备上，主屏幕出现一秒钟，并显示登录屏幕。我尝试更改[self.window.rootViewController dismissViewControllerAnimated:YES completion:nil];和[self.window.rootViewController presentViewController:self.navigationController animated:YES completion:nil];的顺序，但这也不起作用。

我在iOS 9.0 iPad（设备）上运行。但是在模拟器上一切似乎都很好。

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

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

    self->_loginViewController = [[LoginViewController alloc] initWithNibName:nil bundle:nil];    
    self.window.rootViewController = nil;
    self.window.rootViewController = self->_loginViewController;
    [self.window makeKeyAndVisible];

    return YES;
}

- (void)loginUser {

    if([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad) {
       //load xib for iPad
       mainVC = [[MainVC alloc] initWithNibName:@"MainVC~ipad" bundle:nil];

    } else if([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone) {
       //load xib for iPhone
       mainVC = [[MainVC alloc] initWithNibName:@"MainVC~iphone" bundle:nil];
    }

    self.navigationController = nil;
    self.navigationController = [[UINavigationController alloc] initWithRootViewController:mainVC];

    dispatch_async(dispatch_get_main_queue(),^ {
    //    [self.window.rootViewController.navigationController popViewControllerAnimated:YES]; //not working

        [self.window.rootViewController dismissViewControllerAnimated:YES completion:nil]; //not working
        [self.window.rootViewController presentViewController:self.navigationController animated:YES completion:nil]; 

      //not working
      //  [self.window.rootViewController.presentingViewController dismissViewControllerAnimated:YES completion:^{
      //      [self.window.rootViewController presentViewController:self.navigationController animated:YES completion:nil];
      //   }];

    });
}

Answer 1

首先，你要设置LoginViewController作为窗口的rootController，这很好。在您的登录方法中，您尝试在此处没有显示控制器时解除控制器（假设您没有提供任何其他控制器）。您可以删除该行并只显示导航控制器。

Answer 2

为此，我通常会更改rootViewController。在您的情况下，当您的用户登录时替换：

[self.window.rootViewController dismissViewControllerAnimated:YES completion:nil]; //not working
[self.window.rootViewController presentViewController:self.navigationController animated:YES completion:nil];

使用：

self.window.rootViewController = self.navigationController;

然后在用户注销时执行：

self.window.rootViewController = self.loginViewController;