1 mTouchListener = new VelocityTrackingTouchListener();
 2 // Initialize the TextView which will be used to display the logged events
 3 mTextView = (TextView) findViewById(R.id.mytextview);
 4 mTextView.setOnTouchListener(mTouchListener);
 5 private class VelocityTrackingTouchListener implements View.OnTouchListener {
 6     @Override
 7     public boolean onTouch(View view, MotionEvent motionEvent) {
 8         ......
 9         mGestureDetector.onTouchEvent(motionEvent);
10         return true;
11     }
12 }

1 // Instantiate a gesture listener to consume scroll and fling events
2 FlingDetector flingDetector = new FlingDetector();
3 // Pass the FlingDetector to mGestureDetector to receive the appropriate callbacks
4 mGestureDetector = new GestureDetector(this, flingDetector);

 1 private class FlingDetector extends GestureDetector.SimpleOnGestureListener {
 2     public FlingDetector() {
 3         super();
 4     }
 5     @Override
 6     public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
 7     float velocityY) {
 8         updateText("in onFling");
 9         return true;
10     }
11     @Override
12     public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
13         updateText(String.format("onScroll velocity = (%f, %f)", mTouchListener.xVelocity, mTouchListener.yVelocity));
14         return false;
15     }
16 }

 1 switch (action) {
 2     case MotionEvent.ACTION_DOWN:
 3         if (mVelocityTracker == null) {
 4             // Retrieve a new VelocityTracker object to watch the velocity of a motion.
 5             mVelocityTracker = VelocityTracker.obtain();
 6         } else {
 7             // Reset the velocity tracker back to its initial state.
 8             mVelocityTracker.clear();
 9         }
10         // Add a user's movement to the tracker.
11         mVelocityTracker.addMovement(motionEvent);
12     break;
13     case MotionEvent.ACTION_MOVE:
14         mVelocityTracker.addMovement(motionEvent);
15         // When you want to determine the velocity, call
16         // computeCurrentVelocity(). Then call getXVelocity()
17         // and getYVelocity() to retrieve the velocity for each pointer ID.
18         mVelocityTracker.computeCurrentVelocity(1000);
19         // Log velocity of pixels per second
20         xVelocity = mVelocityTracker.getXVelocity(pointerId);
21         yVelocity = mVelocityTracker.getYVelocity(pointerId);
22     break;
23     case MotionEvent.ACTION_CANCEL:
24         // Return a VelocityTracker object back to be re-used by others.
25         mVelocityTracker.recycle();
26     break;
27 }