怎样手势的判断android GestureDetector在android开发中

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;

import android.view.View;

import android.view.View.OnTouchListener;

import android.widget.TextView;

import android.widget.Toast;



public class GestureActivity extends Activity implements OnTouchListener,

        OnGestureListener {



    GestureDetector detector;



    public GestureActivity() {

        detector = new GestureDetector(this);

    }

    

    public void onCreate(Bundle savedInstanceState) {  

            super.onCreate(savedInstanceState);  

            setContentView(R.layout.main);  

            TextView tv = (TextView) findViewById(R.id.TextView001);

            //设置tv的******  

            tv.setOnTouchListener(this);  

            tv.setFocusable(true);

            //必须，view才能够处理不同于Tap（轻触）的hold

            tv.setClickable(true);  

            tv.setLongClickable(true);  

            detector.setIsLongpressEnabled(true);  

    }  

    

    

    /* 

     * 在onTouch()方法中，我们调用GestureDetector的onTouchEvent()方法，将捕捉到的MotionEvent交给GestureDetector 

     * 来分析是否有合适的callback函数来处理用户的手势 

     */   

    public boolean onTouch(View v, MotionEvent event) {  

        return detector.onTouchEvent(event);  

    }  

  

    // 用户轻触触摸屏，由1个MotionEvent ACTION_DOWN触发  

    public boolean onDown(MotionEvent arg0) {  

        Log.i("MyGesture", "onDown");  

        Toast.makeText(this, "onDown", Toast.LENGTH_SHORT).show();  

        return true;  

    }  

      

    /* 

     * 用户轻触触摸屏，尚未松开或拖动，由一个1个MotionEvent ACTION_DOWN触发 



     * 注意和onDown()的区别，强调的是没有松开或者拖动的状态 

     */  

    public void onShowPress(MotionEvent e) {  

        Log.i("MyGesture", "onShowPress");  

        Toast.makeText(this, "onShowPress", Toast.LENGTH_SHORT).show();  

    }  

      

    // 用户（轻触触摸屏后）松开，由一个1个MotionEvent ACTION_UP触发  

    public boolean onSingleTapUp(MotionEvent e) {  

        Log.i("MyGesture", "onSingleTapUp");  

        Toast.makeText(this, "onSingleTapUp", Toast.LENGTH_SHORT).show();  

        return true;  

    }  

      

    // 用户按下触摸屏、快速移动后松开，由1个MotionEvent ACTION_DOWN, 多个ACTION_MOVE, 1个ACTION_UP触发  

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

        Log.i("MyGesture", "onFling");  

        

        // 参数解释：  

        // e1：第1个ACTION_DOWN MotionEvent  

        // e2：最后一个ACTION_MOVE MotionEvent  

        // velocityX：X轴上的移动速度，像素/秒  

        // velocityY：Y轴上的移动速度，像素/秒  

      

        // 触发条件 ：  

        // X轴的坐标位移大于FLING_MIN_DISTANCE，且移动速度大于FLING_MIN_VELOCITY个像素/秒  

          

        final int FLING_MIN_DISTANCE = 100, FLING_MIN_VELOCITY = 200;  

        if (e1.getX() - e2.getX() > FLING_MIN_DISTANCE && Math.abs(velocityX) > FLING_MIN_VELOCITY) {  

            // Fling left  

            Log.i("MyGesture", "Fling left");  

            Toast.makeText(this, "Fling Left", Toast.LENGTH_SHORT).show();  

        } else if (e2.getX() - e1.getX() > FLING_MIN_DISTANCE && Math.abs(velocityX) > FLING_MIN_VELOCITY) {  

            // Fling right  

            Log.i("MyGesture", "Fling right");  

            Toast.makeText(this, "Fling Right", Toast.LENGTH_SHORT).show();  

        } else if(e2.getY()-e1.getY()>FLING_MIN_DISTANCE && Math.abs(velocityY)>FLING_MIN_VELOCITY) {

            // Fling down  

            Log.i("MyGesture", "Fling down");  

            Toast.makeText(this, "Fling down", Toast.LENGTH_SHORT).show();

        } else if(e1.getY()-e2.getY()>FLING_MIN_DISTANCE && Math.abs(velocityY)>FLING_MIN_VELOCITY) {

            // Fling up  

            Log.i("MyGesture", "Fling up");  

            Toast.makeText(this, "Fling up", Toast.LENGTH_SHORT).show();

        }  

        

        

        return false; 

         

    }  

      

    // 用户按下触摸屏，并拖动，由1个MotionEvent ACTION_DOWN, 多个ACTION_MOVE触发  

    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {  

        Log.i("MyGesture", "onScroll");  

        Toast.makeText(this, "onScroll", Toast.LENGTH_LONG).show();  

        return true;  

    }  

      

    // 用户长按触摸屏，由多个MotionEvent ACTION_DOWN触发  

    public void onLongPress(MotionEvent e) {  

        Log.i("MyGesture", "onLongPress");  

        Toast.makeText(this, "onLongPress", Toast.LENGTH_LONG).show();  

    }  

    



}