PresentModalViewController：不返回

Question

我发生了一件非常奇怪的事情。在我的应用程序委托中，我在 UITabBarController 上调用 PresentModalViewController: 来显示实现 loadView 来显示图像的自定义类 (LoadingViewController)。当我在模拟器中针对 iOS 4.x 设备（iPhone 或 iPad）进行测试时，它在所有方向上都运行良好。然而，当我在 3.2 iPad 上进行测试时，只有在纵向方向时它才能正常工作。如果是横向，presentModalViewController: 方法不会返回。 loadView 和 viewDidLoad 方法被调用，但 viewWillAppear: 和 viewDidAppear: 方法不会被调用。

有什么想法吗？

这是LoadingViewController中loadView的代码：

- (void) loadView
{
    CGRect mainScreenBounds = [UIScreen mainScreen].bounds;

    UIImageView * loadingImageView = [[UIImageView alloc] initWithFrame: mainScreenBounds];

    loadingImageView.autoresizesSubviews = YES;
    loadingImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    NSString * splashImageName = [self getSplashImageName: [UIDevice currentDevice].orientation];
    loadingImageView.image = [UIImage imageNamed: splashImageName];

    UIActivityIndicatorView * spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhiteLarge];
    CGRect spinnerFrame = spinner.frame;

    spinnerFrame.origin.x = (mainScreenBounds.size.width - spinnerFrame.size.width) / 2;
    spinnerFrame.origin.y = mainScreenBounds.size.height * 0.7f;

    spinner.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin
                             | UIViewAutoresizingFlexibleRightMargin
                             | UIViewAutoresizingFlexibleTopMargin
                             | UIViewAutoresizingFlexibleBottomMargin;
    spinner.frame = spinnerFrame;
    spinner.hidesWhenStopped = YES;

    [spinner startAnimating];

    [loadingImageView addSubview: spinner];

    // Add a label indicating we are working so the user knows what we are doing.
    UIColor * textColor = [UIColor blueColor];

    CGRect labelFrame = loadingImageView.frame;
    labelFrame.size.height = 40;
    labelFrame.origin.y = spinnerFrame.origin.y - 100;
    UILabel * workingLabel = [[UILabel alloc] initWithFrame: labelFrame];
    workingLabel.font             = [UIFont systemFontOfSize: 18.0];
    workingLabel.textColor        = textColor;
    workingLabel.backgroundColor  = [UIColor clearColor];
    workingLabel.textAlignment    = UITextAlignmentCenter;
    workingLabel.text             = NSLocalizedString(@"Searching for location...", @"Searching for location...");
    workingLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin
                                  | UIViewAutoresizingFlexibleRightMargin
                                  | UIViewAutoresizingFlexibleTopMargin
                                  | UIViewAutoresizingFlexibleBottomMargin
                                  | UIViewAutoresizingFlexibleWidth
                                  | UIViewAutoresizingFlexibleHeight;

    [loadingImageView addSubview: workingLabel];
    [workingLabel release];

    [spinner release];

    self.view = loadingImageView;
    [loadingImageView release];
}

Answer 1

使用 presentModalViewController 时，UITabBarController 应该是 RootViewController。 另外，IOS 3.2 还存在一个问题，即当在 UITabBarController 中横向使用 presentModalViewController 时，如果所有视图控制器都没有覆盖 >shouldAutorotateToInterfaceOrientation 并为横向返回 yes，这将导致 presentModalViewController 挂起。

Answer 2

我们最终得到的解决方案是根本不使用presentModalViewController，而是将LoadingViewController 设置为根视图控制器。显然这不是一个完整的解决方案，但幸运的是它对我们来说已经足够好了。令人沮丧的是不知道为什么presentModalViewController现在不起作用，而它在我们应用程序的早期版本中运行良好。我们所做的一些事情破坏了它。