如何设置第二个UIWindow的方向

Question

I have the following code in my main ViewController viewDidLoad function

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


nav = [[NavWithAutoRotateViewController alloc] initWithRootViewController:self];

[window addSubview:[nav view]];
[window makeKeyAndVisible];


[[self navigationController] setNavigationBarHidden:YES];

My ipad app is currently set to only work in landscape mode and I'm using this new window to show a quicklook document and allowing the nav bar to provide a back button and save options for the document. Main problem is that the new UIWindow orientation doesn't match my main applications UIWindow.

I have a custom UINavigationController above called NavWithAutoRotateController and here is the code for that controller.

-(id)init
{
    if(self)
    {
//        _supportedInterfaceOrientatoin = UIInterfaceOrientationMaskLandscape;
//        _orientation = UIInterfaceOrientationLandscapeLeft;
    }


    return self;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (BOOL)shouldAutorotate
{
    return YES;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
    return YES;
}

-(NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskLandscapeLeft;
}


// Tell the system which initial orientation we want to have
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return UIInterfaceOrientationMaskLandscape;
}

Answer 1

I think I have a solution. The problem seems to be in the assignment of UIViewController to the rootViewController in your extra UIWindow .

If you just assume that you can use the same view controller that your primary UIWindow is using, and then add things as subviews of the new UIWindow, there are orientation issues.

To solve this, I did the following:

UIWindow *newWindow = [[UIWindow alloc] initWithFrame: [UIApplication sharedApplication].keyWindow.frame];
newWindow.windowLevel = UIWindowLevelStatusBar+1;
// You can use a view controller instantiated from a xib or storyboard here if you want.
// Just don't use the view controller already set as a UIWindow's rootViewController.
UIViewController *newViewController = [[UIViewController alloc] init];
newWindow.rootViewController = newViewController;
[newWindow makeKeyAndVisible];
// Add something to the new UIWindow. Can use the new UIViewController's view:
[newViewController.view addSubview: myContentView];
// Or could add it as subview of UIWindow: - either works.
[newWindow addSubview: myContentView];

Doing it this way seems to have solved all the weird issues around rotation. Hope this helps.

Answer 2

Register for status bar frame change notification which is only called (afaik) when orientation changes and then define your new window's orientation..

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(appWillChangeStatusBarFrameNotification:)
                                             name:UIApplicationWillChangeStatusBarFrameNotification
                                           object:nil];

Answer 3

I was having the same problem. Orientation changes were being handled properly using the viewWillTransition method. But my problem was that in some edge case conditions, namely if my device was sitting at an odd angle, the custom UIWindow would initialize in portrait orientation, even though the rootViewController was in landscape. And viewWillTransition isn't called because the device isn't rotated on initial load. I found a really simple solution to my problem that worked in any situation I tested. First initialize your custom UIWindow without a frame. Then set your frame. And voila.. its orientation is what you'd expect.

Swift

let customWindow = UIWindow()
customWindow.frame = CGRect(x: x, y: y, width: w, height: h)
customWindow.rootViewController = self //<your_viewController>
customWindow.windowLevel = .statusBar // or whatever level you need
customWindow.makeKeyAndVisible()

ObjC

UIWindow customWindow = [[UIWindow alloc] init];
customWindow.frame = CGRectMake(x, y, w, h);
customWindow.rootViewController = self;
customWindow.windowLevel = UIWindowLevelStatusBar;
[customWindow makeKeyAndVisible];