GestureDetector应用实例 - JAVA

MotionEvent中定义了基本事件，View中定义了一些简单事件的处理接口，GestureDetector拓展了View中的事件接口，提供了一些复杂事件的接口。框架接口(API)的好处是框架已经帮我们定义好了为什么onDoubleClick表示双击事件，而我们只需要直接使用即可。下面通过实例说明如何使用GestureDetector类实现复杂事件。

package com.sean.gesturetest;  
  
import android.app.Activity;  
import android.content.Context;  
import android.os.Bundle;  
import android.view.GestureDetector;  
import android.view.GestureDetector.OnGestureListener;  
import android.view.MotionEvent;  
import android.widget.Toast;  
  
public class MainActivity extends Activity {  
  
    private GestureDetector gesture;  
    CharSequence onDown = "onDown Event";  
    CharSequence onFling = "onFling Event";  
    CharSequence onLongPress = "onLongPress Event";  
    CharSequence onScroll = "onScroll Event";  
    CharSequence onShowPress = "onShowPress Event";  
    CharSequence onSingleTapUp = "onSingleTapUp Event";  
    private Context mContext = this;  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        gesture = new GestureDetector(this, new myGestureListener() {  
  
        });  
    }  
  
    @Override  
    public boolean onTouchEvent(MotionEvent event) {  
        // TODO Auto-generated method stub  
        return gesture.onTouchEvent(event);  
    }  
  
    private class myGestureListener implements OnGestureListener {  
  
        @Override  
        public boolean onDown(MotionEvent e) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onDown, Toast.LENGTH_SHORT).show();  
            return false;  
        }  
  
        @Override  
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,  
                float velocityY) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onFling, Toast.LENGTH_SHORT).show();  
            return false;  
        }  
  
        @Override  
        public void onLongPress(MotionEvent e) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onLongPress, Toast.LENGTH_SHORT).show();  
        }  
  
        @Override  
        public boolean onScroll(MotionEvent e1, MotionEvent e2,  
                float distanceX, float distanceY) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onScroll, Toast.LENGTH_SHORT).show();  
            return false;  
        }  
  
        @Override  
        public void onShowPress(MotionEvent e) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onShowPress, Toast.LENGTH_SHORT).show();  
        }  
  
        @Override  
        public boolean onSingleTapUp(MotionEvent e) {  
            // TODO Auto-generated method stub  
            Toast.makeText(mContext, onSingleTapUp, Toast.LENGTH_SHORT).show();  
            return false;  
        }  
    }  
}