Android中可自由移动悬浮窗口的实现

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变量为获取的全局变量，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:    //捕获手指触摸按下动作
//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:	//捕获手指触摸移动动作
updateViewPosition();
break;

case MotionEvent.ACTION_UP:    //捕获手指触摸离开动作
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);  //刷新显示
}

}

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;
}
}

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);  //这里简单的用自带的Icom来做演示
//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，便于调整坐标
//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);
}
}

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

/**
* Window type: phone.  These are non-application windows providing
* user interaction with the phone (in particular incoming calls).
* These windows are normally placed above all applications, but behind
* the status bar.
*/
public static final int TYPE_PHONE              = FIRST_SYSTEM_WINDOW+2;

/**
* Window type: system window, such as low power alert. These windows
* are always on top of application windows.
*/
public static final int TYPE_SYSTEM_ALERT       = FIRST_SYSTEM_WINDOW+3;

/** Window flag: this window won't ever get focus. */
public static final int FLAG_NOT_FOCUSABLE      = 0x00000008;

/** Window flag: this window can never receive touch events. */
public static final int FLAG_NOT_TOUCHABLE      = 0x00000010;

/** Window flag: Even when this window is focusable (its
* {@link #FLAG_NOT_FOCUSABLE is not set), allow any pointer events
* outside of the window to be sent to the windows behind it.  Otherwise
* it will consume all pointer events itself, regardless of whether they
* are inside of the window. */
public static final int FLAG_NOT_TOUCH_MODAL    = 0x00000020;