Android MotionEvent.getActionIndex() and MultiTouch

Question

I am trying to get the pointer id whene the event MotionEvent.ACTION_MOVE happens.

I am doing it by calling event.getActionIndex() but it always returns 0 for the second, the third, the forth and the fifth finger.

i am using Gingerbread 2.3.3 on Galaxy S I9000

here is my code

switch (event.getActionMasked()) {
case MotionEvent.ACTION_MOVE: {
    Log.d("D","  getActionIndex()="+event.getActionIndex());
    };break;
}

This is the debug results

05-02 19:20:08.628: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=1
05-02 19:20:08.781: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=1
05-02 19:20:08.820: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=1
05-02 19:20:08.914: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=1
05-02 19:20:09.070: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.187: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.324: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.460: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.523: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.542: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:09.679: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=3
05-02 19:20:09.703: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=3
05-02 19:20:09.847: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=3
05-02 19:20:10.117: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=3
05-02 19:20:10.261: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.281: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.304: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.371: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.410: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.433: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.519: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.558: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=4
05-02 19:20:10.613: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=3
05-02 19:20:10.640: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=2
05-02 19:20:10.656: DEBUG/D(4534): getActionIndex()=0  getPointerCount()=1

Answer 1

I am using this code to dump events, and it works pretty well.

/** Show an event in the LogCat view, for debugging */
private void dumpEvent(MotionEvent event) {
   String names[] = { "DOWN" , "UP" , "MOVE" , "CANCEL" , "OUTSIDE" ,
      "POINTER_DOWN" , "POINTER_UP" , "7?" , "8?" , "9?" };
   StringBuilder sb = new StringBuilder();
   int action = event.getAction();
   int actionCode = action & MotionEvent.ACTION_MASK;
   sb.append("event ACTION_" ).append(names[actionCode]);
   if (actionCode == MotionEvent.ACTION_POINTER_DOWN
         || actionCode == MotionEvent.ACTION_POINTER_UP) {
      sb.append("(pid " ).append(
      action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
      sb.append(")" );
   }
   sb.append("[" );
   for (int i = 0; i < event.getPointerCount(); i++) {
      sb.append("#" ).append(i);
      sb.append("(pid " ).append(event.getPointerId(i));
      sb.append(")=" ).append((int) event.getX(i));
      sb.append("," ).append((int) event.getY(i));
      if (i + 1 < event.getPointerCount())
         sb.append(";" );
   }
   sb.append("]" );
   Log.d(TAG, sb.toString());
}

I got it off this ZDNET article, so I can't take credit for it. I am running on Android 3.0, but the example code was originally written for earlier versions of Android, so it should work for you too.

It looks like you need to call getPointerId rather than getActionIndex.