android 判断左右滑动，上下滑动的GestureDetector简单手势检测

直接加入监听GestureDetector放在需要判断滑动手势的地方：

 import android.app.Activity;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.GestureDetector;
 import android.view.GestureDetector.OnGestureListener;
 import android.view.MotionEvent;  

 public class MainActivity extends Activity {
     protected static final float FLIP_DISTANCE = ;
     GestureDetector mDetector;  

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);  

         mDetector = new GestureDetector(this, new OnGestureListener() {  

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

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

             }  

             @Override
             public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
                 // TODO Auto-generated method stub
                 return false;
             }  

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

             }  

             /**
              *
              * e1 The first down motion event that started the fling. e2 The
              * move motion event that triggered the current onFling.
              */
             @Override
             public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
                 if (e1.getX() - e2.getX() > FLIP_DISTANCE) {
                     Log.i("TAG", "<--- left, left, go go go");
                     return true;
                 }
                 if (e2.getX() - e1.getX() > FLIP_DISTANCE) {
                     Log.i("TAG", "right, right, go go go --->");  //忽然觉得这个log好智障...
                     return true;
                 }
                 if (e1.getY() - e2.getY() > FLIP_DISTANCE) {
                     Log.i("TAG", "向上滑...");
                     return true;
                 }
                 if (e2.getY() - e1.getY() > FLIP_DISTANCE) {
                     Log.i("TAG", "向下滑...");
                     return true;
                 }  

                 Log.d("TAG", e2.getX() + " " + e2.getY());  

                 return false;
             }  

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

     @Override
     public boolean onTouchEvent(MotionEvent event) {
         return mDetector.onTouchEvent(event);
     }
 }