UIWindow's root view controller does not rotate to landscape at app launch

问题

I am developing a xib-based landscape-only app. The app launches in landscape correctly. However, the view in my main ViewController is presented in portrait. That is, it is rotated 90 degrees so that the image appears cropped and does not take up the entire screen. If I use my interface to present a modal view controller then return to the main ViewController, the issue corrects itself (the view is presented in landscape). This problem did not occur under Xcode 4.2. It occurred after upgrading to Xcode 4.3, and the only code changes that were made were automatically implemented by Xcode when I upgraded the project settings.

Based on advice in other posts, I verified my Info.plist settings for Supported Interface Orientations and Initial Interface Orientation. I overrode the shouldAutorotateToInterfaceOrientation method for each of my view controllers to return YES only for landscape orientations. Also, I turned off auto resizing for the view, as I never want the size/orientation of the view to change.

Based on the ideas in this link [1], I suspected the problem is that the view is not receiving the call to change orientation at launch, possibly due to the removal of the MainWindow.xib concept, which appears to be replaced by the following Xcode-inserted code in AppDelegate.m:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];

    return YES;
}

I modified this method to generate a generic root view controller from which my ViewController class is presented, as shown in the code below:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    ViewController* myViewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.viewController = [[UIViewController alloc] init];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    [self.viewController presentModalViewController:myViewController animated:NO];
    return YES;
}

Voila! This solved my problem. However, to me it feels like a change at a fundamental level, which I don't want to make at this point in my development. What I intended to be my root view controller is now a modal view. Does anyone have another solution to this issue?

Thanks in advance!

回答1:

I had this same issue: an app which was meant to be in Landscape that assumed the ViewController was always in Portrait. I made tons of changes to every aspect of the project and info.plist, including giving the main UIWindow a root-view controller which was landscape. It still didn't work. I eventually undid all the changes and just added the two lines noted below to my app delegate:

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{
    [_window addSubview:[_viewController view]];
    glView = _viewController.glView;

    // THIS FIXED ORIENTATION FOR ME IN IOS 6
    _window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    // END

    ...my other setup code here...
}

Nothing else was necessary.

It appears that, for some reason, in iOS 6 the UIWindow root-view-controller setting is sometimes ignored in Interface Builder. I am sure my reasoning is wrong somewhere, but I thought this might well help prod someone in the direction of a fuller, more exhaustive answer.

回答2:

In iOS 8, settings windows frame to the UIScreen is also necessary, as it won't get automatically updated.

self.window.frame = [UIScreen mainScreen].bounds;

来源：https://stackoverflow.com/questions/10096672/uiwindows-root-view-controller-does-not-rotate-to-landscape-at-app-launch

标签

orientation

landscape

uiwindow