UIActivityViewController doesn't show on iPhone + iOS 8

Question

I'm trying to present a UIActivityViewController from an OpenGL view (using libGDX/RoboVM) but am having mixed results.

It works fine on iOS 7 and on iOS 8 iPad, but on iOS 8 iPhone it simply pauses the application without anything happening. Nothing of note in the debug logs, except that the completion block never fires. This is the code:

    UIActivityViewController controller = new UIActivityViewController(activityItems, null);
    List<String> excludedTypes = new ArrayList<String>();
    excludedTypes.add("UIActivityTypePrint");
    excludedTypes.add("UIActivityTypeAssignToContact");
    excludedTypes.add("UIActivityTypeAddToReadingList");
    excludedTypes.add("UIActivityTypeAirDrop");
    excludedTypes.add("UIActivityTypeCopyToPasteboard");
    controller.setExcludedActivityTypes(excludedTypes);
    IOSApplication iosApplication = (IOSApplication)Gdx.app;
    // for iPad (https://groups.google.com/forum/#!topic/robovm/fiGDVf6AAsc)
    int majorOsVersion = Integer.parseInt(System.getProperty("os.version").substring(0, System.getProperty("os.version").indexOf('.')));
    if (majorOsVersion >= 8) 
    {
        UIView sourceView = iosApplication.getUIViewController().getView();
        if (width > 0 && height > 0)
        {
            UIView subView = new UIView(new CGRect(left, top, width, height));
            sourceView.addSubview(subView);
            sourceView = subView;
        }
        UIActivityViewControllerExtensions.getPopoverPresentationController(controller).setSourceView(sourceView);
    }
    iosApplication.getUIViewController().presentViewController(controller, true, null);

I have verified that the method is being called in the "main" thread (hopefully on libGDX that's the same main thread as in a CocoaTouch app)

Answer 1

NullPointerException here:

UIActivityViewControllerExtensions.getPopoverPresentationController(controller).setSourceView(sourceView);

getPopoverPresentationController() returns null on iPhones, which is not a problem in Objective-C land.