android 悬浮窗口的拖动

最近看了一篇博文帮助挺大，我想好多学习android 的人都看过，转过来做个本备份。

package net.xsmile.fv;


import android.app.Application;
import android.view.WindowManager;


public class MyApplication extends Application {
	
	/**
	 * 创建全局变量
	 * 全局变量一般都比较倾向于创建一个单独的数据类文件，并使用static静态变量
	 * 
	 * 这里使用了在Application中添加数据的方法实现全局变量
	 * 注意在AndroidManifest.xml中的Application节点添加android:name=".MyApplication"属性
	 * 
	 */
	private WindowManager.LayoutParams wmParams=new WindowManager.LayoutParams();


	public WindowManager.LayoutParams getMywmParams(){
		return wmParams;
	}
}

package net.xsmile.fv;

import android.content.Context;
import android.util.Log;
import android.view.MotionEvent;
import android.view.WindowManager;
import android.widget.ImageView;

public class MyFloatView extends ImageView {
	private float mTouchStartX;
    private float mTouchStartY;
    private float x;
    private float y;
    
    
    private WindowManager wm=(WindowManager)getContext().getApplicationContext().getSystemService("window");
    
    //此wmParams为获取的全局变量，用以保存悬浮窗口的属性
    private WindowManager.LayoutParams wmParams = ((MyApplication)getContext().getApplicationContext()).getMywmParams();

	public MyFloatView(Context context) {
		super(context);		
		// TODO Auto-generated constructor stub
	}
	
	 @Override
	 public boolean onTouchEvent(MotionEvent event) {
		 
		 
		 //获取相对屏幕的坐标，即以屏幕左上角为原点		 
	     x = event.getRawX();   
	     y = event.getRawY()-25;   //25是系统状态栏的高度
	     Log.i("currP", "currX"+x+"====currY"+y);
	     switch (event.getAction()) {
	        case MotionEvent.ACTION_DOWN:
	        	//获取相对View的坐标，即以此View左上角为原点
	        	mTouchStartX =  event.getX();  
                mTouchStartY =  event.getY();
                
	            Log.i("startP", "startX"+mTouchStartX+"====startY"+mTouchStartY);
	            
	            break;
	        case MotionEvent.ACTION_MOVE:	            
	            updateViewPosition();
	            break;

	        case MotionEvent.ACTION_UP:
	        	updateViewPosition();
	        	mTouchStartX=mTouchStartY=0;
	        	break;
	        }
	        return true;
		}
	 
	 private void updateViewPosition(){
		//更新浮动窗口位置参数
		wmParams.x=(int)( x-mTouchStartX);
		wmParams.y=(int) (y-mTouchStartY);
	    wm.updateViewLayout(this, wmParams);
	    
	 }

}

package net.xsmile.fv;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.Gravity;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

public class MyFloatViewActivity extends Activity {
    /** Called when the activity is first created. */
	
	private WindowManager wm=null;
	private WindowManager.LayoutParams wmParams=null;
	
	private MyFloatView myFV=null;

	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //创建悬浮窗口
        createView();
    
    }
    
  
    
    private void createView(){
    	myFV=new MyFloatView(getApplicationContext());
    	myFV.setImageResource(R.drawable.icon);
    	//获取WindowManager
    	wm=(WindowManager)getApplicationContext().getSystemService("window");
        //设置LayoutParams(全局变量）相关参数
    	wmParams = ((MyApplication)getApplication()).getMywmParams();

         /**
         *以下都是WindowManager.LayoutParams的相关属性
         * 具体用途可参考SDK文档
         */
        wmParams.type=LayoutParams.TYPE_PHONE;   //设置window type
        wmParams.format=PixelFormat.RGBA_8888;   //设置图片格式，效果为背景透明

        //设置Window flag
        wmParams.flags=LayoutParams.FLAG_NOT_TOUCH_MODAL
                              | LayoutParams.FLAG_NOT_FOCUSABLE;
        /*
         * 下面的flags属性的效果形同“锁定”。
         * 悬浮窗不可触摸，不接受任何事件,同时不影响后面的事件响应。
         wmParams.flags=LayoutParams.FLAG_NOT_TOUCH_MODAL 
                               | LayoutParams.FLAG_NOT_FOCUSABLE
                               | LayoutParams.FLAG_NOT_TOUCHABLE;
        */
        
        
        wmParams.gravity=Gravity.LEFT|Gravity.TOP;   //调整悬浮窗口至左上角
        //以屏幕左上角为原点，设置x、y初始值
        wmParams.x=0;
        wmParams.y=0;
        
        //设置悬浮窗口长宽数据
        wmParams.width=40;
        wmParams.height=40;
    
        //显示myFloatView图像
        wm.addView(myFV, wmParams);
    	
    }
    
    @Override
    public void onDestroy(){
    	super.onDestroy();
    	//在程序退出(Activity销毁）时销毁悬浮窗口
    	wm.removeView(myFV);
    }
    
   
    
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="net.xsmile.fv"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:name=".MyApplication" android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".MyFloatViewActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />


</manifest> 

转自：http://www.xsmile.net/?p=452