public interface WindowManager implements ViewManager

float x = event.getRawX();
float y = event.getRawY()-25; //25是系统状态栏的高度

wmParams.x=(int)( x-mTouchStartX);
wmParams.y=(int) (y-mTouchStartY);

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

import android.app.Application;
import android.view.WindowManager;
public class MyApplication extends Application {
/**
* 创建全局变量
* 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;
}
}

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(Context.WINDOW_SERVICE);
//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();
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);
}
}

import android.app.Activity;
import android.content.Context;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.view.WindowManager.LayoutParams;
public class MyFloatViewActivity extends Activity{
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.angry_birds);
//获取WindowManager
wm=(WindowManager)getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
//设置LayoutParams(全局变量）相关参数
wmParams = ((MyApplication)getApplication()).getMywmParams();
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;
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);
}
}