android怎么为activity开发手势识别

/*
 *  for左右手势
 *  1.复制下面的内容到目标Activity
 *  2.目标Activity的onCreate()调用initGesture()
 *  3.目标Activity需implements OnTouchListener, OnGestureListener
 */
   private GestureDetector mGestureDetector;
   private int verticalMinDistance = 180;
   private int minVelocity         = 0;

 

   private void initGesture() {
    mGestureDetector = new GestureDetector((OnGestureListener) this);
   }

  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

       if (e1.getX() - e2.getX() > verticalMinDistance && Math.abs(velocityX) > minVelocity) {

           // 切换Activity
           // Intent intent = new Intent(ViewSnsActivity.this, UpdateStatusActivity.class);
           // startActivity(intent);
           //Toast.makeText(this, "向左手势", Toast.LENGTH_SHORT).show();
       } else if (e2.getX() - e1.getX() > verticalMinDistance && Math.abs(velocityX) > minVelocity) {

           // 切换Activity
           // Intent intent = new Intent(ViewSnsActivity.this, UpdateStatusActivity.class);
           // startActivity(intent);
        //Toast.makeText(this, "向右手势", Toast.LENGTH_SHORT).show();
           finish();
           overridePendingTransition(R.anim.push_right_in, R.anim.push_right_out);
       }

       return false;
   }

@Override
public void onLongPress(MotionEvent arg0) {
 // TODO Auto-generated method stub

}

@Override
public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,
  float arg3) {
 // TODO Auto-generated method stub
 return false;
}

@Override
public void onShowPress(MotionEvent arg0) {
 // TODO Auto-generated method stub

}

@Override
public boolean onSingleTapUp(MotionEvent arg0) {
 // TODO Auto-generated method stub
 return false;
}

@Override
public boolean onTouch(View v, MotionEvent event) {
 // TODO Auto-generated method stub
 return mGestureDetector.onTouchEvent(event);
}

@Override
public boolean onDown(MotionEvent arg0) {
 // TODO Auto-generated method stub
 return false;
}

@Override 
public boolean dispatchTouchEvent(MotionEvent ev) {
 mGestureDetector.onTouchEvent(ev);
 return super.dispatchTouchEvent(ev);
  } 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="-100%p" android:toXDelta="0"
        android:duration="500" />
    <alpha android:fromAlpha="0.1" android:toAlpha="1.0"
        android:duration="500"/>
</set> 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="0" android:toXDelta="100%p"
        android:duration="500" />
    <alpha android:fromAlpha="1.0" android:toAlpha="0.1"
        android:duration="500"/>
</set>