void printSamples(MotionEvent ev) {
      final int historySize = ev.getHistorySize();
      final int pointerCount = ev.getPointerCount();
      for (int h = 0; h < historySize; h++) {
          System.out.printf("At time %d:", ev.getHistoricalEventTime(h));
          for (int p = 0; p < pointerCount; p++) {
              System.out.printf("  pointer %d: (%f,%f)",
                  ev.getPointerId(p), ev.getHistoricalX(p, h), ev.getHistoricalY(p, h));
          }
      }
     System.out.printf("At time %d:", ev.getEventTime());
     for (int p = 0; p < pointerCount; p++) {
         System.out.printf("  pointer %d: (%f,%f)",
             ev.getPointerId(p), ev.getX(p), ev.getY(p));
     }
 }