点击button拖动效果

这个简单的代码段可以熟悉getX(),getRawX()等方法,实现按钮的拖动效果:
Java代码 
package com.example;  
 
import android.app.Activity;  
import android.os.Bundle;  
import android.widget.Button;  
import android.view.MotionEvent;  
import android.view.View;  
import android.view.View.OnTouchListener;  
 
public class ButtonDrag extends Activity {  
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        final Button btn = (Button) findViewById(R.id.btn_hello);  
 
        btn.setOnTouchListener(new OnTouchListener() {  
            int[] temp = new int[] { 0, 0 };  
 
            public boolean onTouch(View v, MotionEvent event) {  
 
                int eventaction = event.getAction();  
 
                int x = (int) event.getRawX();  
                int y = (int) event.getRawY();  
 
                switch (eventaction) {  
 
                case MotionEvent.ACTION_DOWN:  
                    temp[0] = (int) event.getX();  
                    temp[1] = (int) event.getY();  
                    break;  
                case MotionEvent.ACTION_MOVE:  
                    v.layout(x - temp[0], y - temp[1], x + v.getWidth()  
                            - temp[0], y + v.getHeight() - temp[1]);  
                    // run in non_UI thread  
                    v.postInvalidate();  
                    break;  
 
                case MotionEvent.ACTION_UP:  
                    break;  
                }  
                return false;  
            }  
 
        });  
 
    }  
 
}