在UIInputViewController子类中检测旋转。 键盘扩展

Question

I have been developing custom keyboard extension and I need to update few constraints programatically after device rotates. I have been trying to detect user interface rotation in my UIInputViewController subclass but without success. These methods are not called when device rotates:

-(void)willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>) coordinator { NSLog(@"Orientation changed"); }

-(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator { NSLog(@"Orientation changed"); }

I've also tried to observe UIDeviceOrientationDidChangeNotification but it doesn't work either.

Does anyone know how to detect rotation in UIInputViewController ?

Answer 1

You're correct - those methods are not called in the UIInputViewController subclass for Keyboard Extensions (not sure about other extension types).

You need to override viewDidLayoutSubviews .

For example, if you wanted to update the layout of a UICollectionView subview of your keyboard when the device rotates, you'd do something like this:

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];

    [self.keyboard.collectionView performBatchUpdates:nil completion:nil];
}

In your case you can check the orientation of the device in viewDidLayoutSubviews, and then apply/modify constraints appropriately.

Answer 2

It looks like Apple didn't provide this API method to the UIInputViewController.

You can infer the device orientation if the device width is greater than device height in viewWillAppear

Answer 3

Swift 4.2

  override func didRotate(from fromInterfaceOrientation: UIInterfaceOrientation) {        
       let screen = UIScreen.main.bounds
        if screen.width < screen.height {
            print("!!! portrait")
        } else {
            print("!!! landspace")
        }
     }