工作中遇到一些項目需要把窗體顯示在最上層，像來電彈窗顯示電話號碼等信息或攔截短信信息顯示給用戶，我們想這些數據放在最上層，activity就滿足不了我們的需求了，有些開發者使用了循環顯示Toast的方式，toast是不能獲得焦點的，這種方法是不可取的。這個時候，我們如何處理呢？
?????? 原來，整個Android的窗口機制是基于一個叫做 WindowManager，這個接口可以添加view到屏幕，也可以從屏幕刪除view。它面向的對象一端是屏幕，另一端就是View，直接忽略我們以前的Activity或者Dialog之類的東東。其實我們的Activity或者Diolog底層的實現也是通過WindowManager，這個 WindowManager是全局的，整個系統就是這個唯一的東東。它是顯示View的最底層了。

???WindowManager主要用來管理窗口的一些狀態、屬性、view增加、刪除、更新、窗口順序、消息收集和處理等。通過Context.getSystemService(Context.WINDOW_SERVICE)的方式可以獲得WindowManager的實例.

WindowManager繼承自ViewManager，里面涉及到窗口管理的三個重要方法，分別是：

??? ?* addView();

???? * updateViewLayout();

???? * removeView();?

?

效果圖如下：

?

?

可以移動的懸浮框實現代碼如下：

[java]?view plaincopyprint?

public?class?WindowManageDemoActivity?extends?Activity?{??

???

private?WindowManager?mWindowManager;??

?private?WindowManager.LayoutParams?param;??

?private?FloatView?mLayout;??

????/**?Called?when?the?activity?is?first?created.?*/??

????@Override??

????public?void?onCreate(Bundle?savedInstanceState)?{??

????????super.onCreate(savedInstanceState);??

????????setContentView(R.layout.main);??

????????????????

????????showView();??

????}??

????private?void?showView(){??

?????mLayout=new?FloatView(getApplicationContext());??

?????mLayout.setBackgroundResource(R.drawable.faceback_head);??

?????//獲取WindowManager??

?????mWindowManager=(WindowManager)getApplicationContext().getSystemService(Context.WINDOW_SERVICE);??

????????//設置LayoutParams(全局變量）相關參數??

?????param?=?((MyApplication)getApplication()).getMywmParams();??

??

?????param.type=WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;?????//?系統提示類型,重要??

?????param.format=1;??

?????param.flags?=?WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;?//?不能搶占聚焦點??

?????param.flags?=?param.flags?|?WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH;??

?????param.flags?=?param.flags?|?WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;?//?排版不受限制??

????????

?????param.alpha?=?1.0f;??

??????????

?????param.gravity=Gravity.LEFT|Gravity.TOP;???//調整懸浮窗口至左上角??

????????//以屏幕左上角為原點，設置x、y初始值??

?????param.x=0;??

?????param.y=0;??

??????????

????????//設置懸浮窗口長寬數據??

?????param.width=140;??

?????param.height=140;??

??????????

????????//顯示myFloatView圖像??

?????mWindowManager.addView(mLayout,?param);??

???????

????}??

????@Override??

????public?void?onDestroy(){??

?????super.onDestroy();??

?????//在程序退出(Activity銷毀）時銷毀懸浮窗口??

?????mWindowManager.removeView(mLayout);??

????}??

}??

?

[java]?view plaincopyprint?

public?class?FloatView?extends?View?{??

?private?float?mTouchStartX;??

????private?float?mTouchStartY;??

????private?float?x;??

????private?float?y;??

??????

????private?WindowManager?wm=(WindowManager)getContext().getApplicationContext().getSystemService(Context.WINDOW_SERVICE);??

????private?WindowManager.LayoutParams?wmParams?=?((MyApplication)getContext().getApplicationContext()).getMywmParams();??

??

?public?FloatView(Context?context)?{??

??super(context);????

??//?TODO?Auto-generated?constructor?stub??

?}??

???

??@Override??

??public?boolean?onTouchEvent(MotionEvent?event)?{??

?????

?????

???//獲取相對屏幕的坐標，即以屏幕左上角為原點?????

??????x?=?event.getRawX();?????

??????y?=?event.getRawY()-25;???//25是系統狀態欄的高度??

??????Log.i("currP",?"currX"+x+"====currY"+y);??

??????switch?(event.getAction())?{??

?????????case?MotionEvent.ACTION_DOWN:??

??????????//獲取相對View的坐標，即以此View左上角為原點??

??????????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(){??

??//更新浮動窗口位置參數??

??wmParams.x=(int)(?x-mTouchStartX);??

??wmParams.y=(int)?(y-mTouchStartY);??

?????wm.updateViewLayout(this,?wmParams);??

???????

??}??

??

}??

?

?

?

[java]?view plaincopyprint?

public?class?MyApplication?extends?Application?{??

???

/**?

??*?創建全局變量?

??*?全局變量一般都比較傾向于創建一個單獨的數據類文件，并使用static靜態變量?

??*??

??*?這里使用了在Application中添加數據的方法實現全局變量?

??*?注意在AndroidManifest.xml中的Application節點添加android:name=".MyApplication"屬性?

??*??

??*/??

?private?WindowManager.LayoutParams?wmParams=new?WindowManager.LayoutParams();??

??

??

?public?WindowManager.LayoutParams?getMywmParams(){??

??return?wmParams;??

?}??

??

}??

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