Swipe Up/Down gestures working fine with iOS emulator but not on actual device

[ghost]

Swipe up/down working fine with iOS 9.1 and 9.2 (iPhone 5S emulator). When I tried on an actual device (iPhone 5S running iOS 9.2) my app would crash.

System.MissingMethodException: Constructor on type 'UIKit.UISwipeGestureRecognizer' not found.

I can post the full stack trace if required. The app wouldn't crash when trying to swipe up or down, it was before, when configuring the gesture recognisers, with this code:

            SwipeGestureRecognizer LeftSwipeUpGestureRecognizer = new SwipeGestureRecognizer();
            LeftSwipeUpGestureRecognizer.Direction = SwipeGestureRecognizerDirection.Up;
            LeftSwipeUpGestureRecognizer.OnAction += (s, e) => HandleSwipeUp(SlidesArray, BubblesArray);
            LeftStackLayout.GestureRecognizers.Add(LeftSwipeUpGestureRecognizer);

            SwipeGestureRecognizer LeftSwipeDownGestureRecognizer = new SwipeGestureRecognizer();
            LeftSwipeDownGestureRecognizer.Direction = SwipeGestureRecognizerDirection.Down;
            LeftSwipeDownGestureRecognizer.OnAction += (s, e) => HandleSwipeDown(SlidesArray, BubblesArray);
            LeftStackLayout.GestureRecognizers.Add(LeftSwipeDownGestureRecognizer);
            LeftStackLayout.ProcessGestureRecognizers(); // This does both up and down.

I.e. commenting that code out to ignore the swipe up/down would stop the app from crashing.

Is this something you or anyone has seen before?

Thanks

[ghost]

Actually, having just downloaded a fresh copy of the code from this repo, it doesn't work correctly on my iPad.

The app loads ok but most (if not all) pages appear blank, i.e. when I tap "Swipe" to test the swiping features I am presented with a blank screen.

The iPad is running iOS 9.2.

Again, however, the emulator runs perfectly with no issues and swipe gestures work correctly. And that's iOS 9.2 too.

Cheers

[ckogevina]

I think this is a Xamarin bug similar to this mentioned here: https://bugzilla.xamarin.com/show_bug.cgi?id=37563
You can bypass it if you set linker behavior: Don't link

[rohitvipin]

run into it and only suggested approach is dont link?

[rohitvipin]

To ensure linker does not remove your Gestures add the following to your AppDelegate FinishedLaunching method

    /// <summary>
    /// To ensure gestures not getting stripped out in linking. 
    /// </summary>
    private static void InitializeGestures()
    {
        GestureRecognizerExtensions.Factory = new NativeGestureRecognizerFactory();
        var uiSwipeGestureRecognizer = new UISwipeGestureRecognizer(() => { });
        var nativeSwipeGestureRecognizer = new NativeSwipeGestureRecognizer();
        var uiSwipeGestureRecognizer2 = new UISwipeGestureRecognizer(nativeSwipeGestureRecognizer2 => { });
        var uiSwipeGestureRecognizer3 = new UISwipeGestureRecognizer();
    }