How to capture the onSwipeDown event on google glass using a native app?

Question

I was able to capture most of the events triggered by the touchpad of a google glass using the SimpleOnGestureListener in a native app.

With the following code you can capture these events

MainActivity.java:

private GestureDetector gestureDetector;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    gestureDetector = new GestureDetector(this, new MyGestureListener());
}

@Override
public boolean onGenericMotionEvent(MotionEvent event)
{
    gestureDetector.onTouchEvent(event);
    return true;
}

MyGestureListener:

public class MyGestureListener extends android.view.GestureDetector.SimpleOnGestureListener
{
    @Override
    public boolean onFling(MotionEvent start, MotionEvent finish, float velocityX, float velocityY)
    {     
        // check for velocity direction to identify swipe forward / backward / up and down
        return true;
    } 
}

I found two different sources for gesture processing I tried:

1. Capture Glass D-Pad events in Android
2. Capturing Gesture Controls for Use in Native Android Glass Apps

But with none of them I was able to catch the swipeDown event.

The callback onFling() is only called on "swipe forward", "swipe backward" and "swipe up" but never called when I do a "swipe down".

Any hints or have you already managed to catch the swipe down? I am really clueless here.

Answer 1

Here is the (weird) solution.

It seems that the swipeDown gesture is not really a gesture but more a button click.

That means that you should use the callback methods of your activity to capture these events.

private static final int KEY_SWIPE_DOWN = 4;

@Override
public boolean onKeyUp(int keyCode, KeyEvent event)
{
    if (keyCode == KEY_SWIPE_DOWN)
    {
        // there was a swipe down event
        return true;
    }
    return false;
}

I think you do not need to care about the onKeyDown() callback because this callback is only triggered directly before the onKeyUp() event and not when you are beginning the gesture.