使用onFling和ViewPager

Question

我正在尝试为GestureDetector实现一个水平navegation和onFling的ViewPager，用于垂直navegation。 ViewPager没关系，但onFling不起作用。代码：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.test_flipper);
    cxt = this;

    viewPageAdapter = new MyPagerAdapter();
    viewPager = (ViewPager) findViewById(R.id.mypager);
    viewPager.setAdapter(viewPageAdapter);

    viewFlipper = (ViewFlipper)findViewById(R.id.flipper);
    slideLeftIn = AnimationUtils.loadAnimation(this, R.anim.slide_left_in);
    slideLeftOut = AnimationUtils.loadAnimation(this, R.anim.slide_left_out);
    slideRightIn = AnimationUtils.loadAnimation(this, R.anim.slide_right_in);
    slideRightOut = AnimationUtils.loadAnimation(this, R.anim.slide_right_out);

    gestureDetector = new GestureDetector(new VerticalGesture());

    gestureListener = new View.OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {
            if (gestureDetector.onTouchEvent(event)) {
                return true;
            }
            return false;
        }
    };      



}

public boolean onTouchEvent(MotionEvent event) {
    if (gestureDetector.onTouchEvent(event))
        return true;
    else
        return false;
}

和onFling工具：

    public  class VerticalGesture extends GestureDetector.SimpleOnGestureListener{

    private static final float SWIPE_MAX_OFF_PATH = 200;
    private static final float MIN_DISTANCE_SWIPE = 10;
    private static final float MIN_VELOCITY = 10;

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        try {
            if (Math.abs(e1.getX() - e2.getX()) > SWIPE_MAX_OFF_PATH)
                return false;
            // top to down swipe
            if(e1.getY() - e2.getY() > MIN_DISTANCE_SWIPE && Math.abs(velocityY) > MIN_VELOCITY) {
                viewFlipper.setInAnimation(slideLeftIn);
                viewFlipper.setOutAnimation(slideLeftOut);
                viewFlipper.showNext();
            }  else if (e2.getY() - e1.getY() > MIN_DISTANCE_SWIPE && Math.abs(velocityY) > MIN_VELOCITY) {
                viewFlipper.setInAnimation(slideRightIn);
                viewFlipper.setOutAnimation(slideRightOut);
                viewFlipper.showPrevious();
            }
        } catch (Exception e) {
            // nothing
        }
        return false;
    }

    @Override
    public boolean onDown(MotionEvent e) {
        return true;        
    }
}

PagerAdapter类：

public class MyPagerAdapter extends PagerAdapter{


    @Override
    public int getCount() {
        return NUM_MAX_VIEWS;
    }

    @Override
    public Object instantiateItem(View collection, int position) {
        TextView tv = new TextView(cxt);
        tv.setText("Dashboard " + position);
        tv.setTextColor(Color.WHITE);
        tv.setTextSize(30);

        ((ViewPager) collection).addView(tv,0);

        return tv;
    }

    @Override
    public void destroyItem(View collection, int position, Object view) {
        ((ViewPager) collection).removeView((TextView) view);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view==((TextView)object);
    }

    @Override
    public void finishUpdate(View arg0) {}


    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {}

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void startUpdate(View arg0) {}

}

欢迎任何指南或资源。感谢