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 = 50;  
    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);  
    }  
}