This demonstrates how to implement the onTouch(...) callback method within a Fragment in order to scale/zoom out the Fragment's root view when a user drags their finger up or down. Note: You can use the nineoldandroids lib to get this to work on pre-Honeycomb devices.

ZoomFragment.java

public class ZoomFragment implements OnTouchListener {

    private static final float MIN_SCALE = 0.95f;
    
    private float mLastScaleFactor = 0;
    private float mTouchY;

    @Override
    public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
        mView = inflater.inflate(R.layout.fragment_layout, container, false);
        mView.setOnTouchListener(this);  
        return mView;
    }
    
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mLastScaleFactor = 0;
                mTouchY = event.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                int[] viewCoords = new int[2];
                v.getLocationOnScreen(viewCoords);
                
                int touchY = (int) event.getY();
                float yDiff = Math.abs(mTouchY - touchY);
                float dragHeightPercentage = yDiff / (float) getView().getHeight();
                
                mLastScaleFactor = 1 - ((1 - MIN_SCALE) * dragHeightPercentage);
                
                ObjectAnimator scaleDownX = ObjectAnimator.ofFloat(v, "scaleX", mLastScaleFactor);
                ObjectAnimator scaleDownY = ObjectAnimator.ofFloat(v, "scaleY", mLastScaleFactor);

                scaleDownX.setDuration(0);
                scaleDownY.setDuration(0);

                AnimatorSet scaleDown = new AnimatorSet();
                scaleDown.play(scaleDownX).with(scaleDownY);
                scaleDown.start();
                break;
            case MotionEvent.ACTION_UP:
                ObjectAnimator scaleUpX = ObjectAnimator.ofFloat(v, "scaleX", 1f);
                ObjectAnimator scaleUpY = ObjectAnimator.ofFloat(v, "scaleY", 1f);

                scaleUpX.setDuration(250);
                scaleUpY.setDuration(250);

                AnimatorSet scaleUp = new AnimatorSet();
                scaleUp.play(scaleUpX).with(scaleUpY);
                scaleUp.start();
                
                mLastScaleFactor = 0;
                mTouchY = 0;
                break;
            default:
                break;
        }
        
        return true;
    }
    
}

It's been a long time since you wrote this "how to," so the API has probably change since. I'm struggling with this now and can't get onTouch to catch events in a fragment. I noticed in your example that your class doesn't extend Fragment (in my case android.support.v4.app.Fragment). Because I'm extending Fragment, I had to set the listener in my onViewCreated() method: view.setOnTouchListener(this). I don't have any syntax or runtime errors, the touch events simply don't fire. Do you have any words of wisdom? Thanks.

@ward459 i know this is old but it might help someone who comes back here, but maybe create a baseZoomFragment

public class BaseZoomFragment extends android.support.v4.app.Fragment implements OnTouchListener