iOS7中表格下方的黑色空白区域，带有嵌套的UIViewControllers

Question

I get some black empty area below a UITableViewController when nested in a certain way (iOS7). Would anybody know why that happens?

(obviously the code is a 100% stripped down version of the actual app's code)

    - (BOOL) application:(UIApplication *) application didFinishLaunchingWithOptions:(NSDictionary *) launchOptions {
    UITabBarController *tabBarController = [UITabBarController new];
    UITableViewController *demoViewController = [UITableViewController new];
    UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:demoViewController];

    tabBarController.tabBar.translucent = NO;
    navigationController.navigationBar.translucent = NO;

    // THESE LINES INTRODUCE A BLACK AREA BELOW THE TABLE
    InBetweenViewController *inBetweenViewController = [InBetweenViewController new];
    [inBetweenViewController addChildViewController:navigationController];
    [inBetweenViewController.view addSubview:navigationController.view];
    tabBarController.viewControllers = @[ inBetweenViewController ];

    // INSTEAD, THIS LINE WORKS CORRECTLY
    /* tabBarController.viewControllers = @[ navigationController ]; */

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.rootViewController = tabBarController;
    [self.window makeKeyAndVisible];
    return YES;
}

@implementation InBetweenViewController
- (void) viewWillLayoutSubviews {
    [super viewWillLayoutSubviews];
    for (UIView *subview in self.view.subviews) {
        subview.frame = self.view.bounds;
    }
}

@end

Answer 1

It's because your inBetweenViewController doesn't know how to render its childViewController . You just add the the view of that controller without any further instructions. It should be possible to solve this by using a simple autoresizingMask . You then also need to make sure that the subview's size is the same as the superview's size when you add it. If you need more details on how to do that, let me know.