iOS 8.3 iPad上的自定义UIWindow可在模拟器上运行，但不能在设备上运行

Question

We have UIWindow code that has worked for years to put up a "blocker" screen. We noticed recently that on an iOS 8.3 iPad the blocker is offset 256 pixels when the blocker is displayed in the landscape orientation. There are few oddities:

1) This does not happen on the simulator, only the device

2) If the blocker is shown in portrait it is fine

3) If the blocker is shown in portrait and then rotated to landscape it is fine.

4) The gap is 256 pixels, which is the difference between the width and the height, ie, 1024 - 768 = 256.

We've recently updated to Xcode 6, so this could be a factor as well...

This problem can be easily replicated by using the default Xcode Master Detail project and making a few minor changes to the "insertNewObject" method as shown here:

    UIWindow *blocker;

    - (void)insertNewObject:(id)sender {


            blocker = [[UIWindow alloc] init];
            [blocker setBackgroundColor:[UIColor colorWithRed:.0 green:.0 blue:.0 alpha:.8]];
            [blocker makeKeyAndVisible];

            CGRect r = CGRectMake(0, 0, 768, 1024);
            [blocker setFrame:r];


    }

If you run this code on the simulator, and tap the "+" button you get:

which is what we expect.

However, this same exact code, running on our 8.3 iPad device gives us:

Any ideas of why the simulator works and the device doesn't? Suggestions? Other things to try?

[UPDATE] We've only found one device where is this a problem, an iPad 2. We've also discovered that setting the rootViewController on the UIWindow "solves" the problem.

Answer 1

Here is the fix we used:

blocker = [[UIWindow alloc] init];
[blocker setBackgroundColor:[UIColor colorWithRed:.0 green:.0 blue:.0 alpha:.8]];

UIViewController *blockerRoot = [UIViewController new];
blocker.rootViewController = blockerRoot;
CGRect r = [[UIScreen mainScreen] bounds];
[blocker setFrame:r];

[blocker makeKeyAndVisible];

We also were able to remove rotation adjustment code since now the view controller managed it properly for us (at least for iOS 8 and later). Here's the code we now use for that: (called when the screen is rotated)

    - (void)adjustForRotation
    {

        if ([UIUtil iOS8OrLater]){
        // iOS 8 handles this correctly, no need for adjustments...
            return;
        }

        UIInterfaceOrientation io = [[UIApplication sharedApplication] statusBarOrientation];
        if (UIInterfaceOrientationIsLandscape(io)){
            CGRect r = [[UIScreen mainScreen] bounds];
            CGFloat x = r.size.height / 2.0;
            CGFloat y = r.size.width / 2.0;
            self.center = CGPointMake(x, y);       
        }
        return;
    }

Answer 2

You are explicitly set the frame of the blocker to the portrait dimensions. It is only being changed when the device is rotated.

Instead, try getting the size from the display to current window when the blocker is being created.