解除 modalViewController 的 modalViewController

Question

所以我有一个 UITabBarController 应用程序，我想显示一个登录页面，所以我这样做了：

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(userDidLogin:) name:UserDidLoginNotification object:nil];
LoginViewController* loginViewController = [[LoginViewController alloc] init];
        self.tabBarController.selectedViewController = [self.tabBarController.viewControllers objectAtIndex:0];
        [self.tabBarController.selectedViewController presentModalViewController:loginViewController animated:NO];
        [loginViewController release];

在我的 LoginViewController 中，我也可以显示另一个 modalViewController：

- (void) twitterLogin: (UIViewController *) askingView
{
    UIViewController *controller = [SA_OAuthTwitterController controllerToEnterCredentialsWithTwitterEngine: _twitter delegate: self];

    if (controller) {
        self.askingView = askingView;
        [askingView presentModalViewController: controller animated: YES];
    }
}

我有以下方法，其中 AskView 是 LoginViewController， 当我想关闭它时，我这样做：

[self.askingView dismissModalViewControllerAnimated:YES];
    [[NSNotificationCenter defaultCenter] postNotificationName:UserDidLoginNotification object:nil];

但是，这不会关闭 LoginViewController 并显示 UITabBarController 视图。它只是关闭从 LoginvVIewController 显示的我的 modalViewController 。我在这里做错了什么？我还收到以下错误：

attempt to dismiss modal view controller whose view does not currently appear. self = <LoginViewController: 0x2aff70> modalViewController = <SA_OAuthTwitterController: 0x2d2a80>
2011-09-16 09:45:37.750 VoteBooth[4614:707] attempt to dismiss modal view controller whose view does not currently appear. self = <MainViewController: 0x29fec0> modalViewController = <LoginViewController: 0x2aff70>

Answer 1

为了关闭在另一个模态视图上呈现的模态视图，您必须在父级的父级上调用 dismissModalViewControllerAnimated: 。我已经在我的一些应用程序中使用了它，并且它对我来说非常有效（经过许多艰苦的时间试图弄清楚）。这正是我所使用的：

[[[self parentViewController] parentViewController] dismissModalViewControllerAnimated:YES];

Answer 2

if ([self respondsToSelector:@selector(presentingViewController)]) {
    [self.presentingViewController.presentingViewController dismissModalViewControllerAnimated:YES]; // for IOS 5+
} else {
    [self.parentViewController.parentViewController dismissModalViewControllerAnimated:YES]; // for pre IOS 5
}

Answer 3

如果你有一个动态的用户体验并且不知道要去找多少个父母，你可以使用这个递归函数来弄清楚......

- (void) goHome
{
    //Dismiss modal back to home page
    int numberOfVcsToDismiss = [self findRootViewController:self];
    [self dismissToRootVc:numberOfVcsToDismiss];
}

- (int) findRootViewController:(UIViewController*)vc
{
    if(vc)
    {
        return 1 + [self findRootViewController:vc.presentingViewController];
    }
    return 0;
}

- (void) dismissToRootVc:(int)count
{
    if(count == 1)
        [self dismissViewControllerAnimated:YES completion:^{}];
    if(count == 2)
        [self.presentingViewController dismissViewControllerAnimated:YES completion:^{}];
    if(count == 3)
        [self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:^{}];
    if(count == 4)
        [self.presentingViewController.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:^{}];
    if(count == 5)
        [self.presentingViewController.presentingViewController.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:^{}];
    //etc....
}