本文實例講述了Android中懸浮窗口的實現原理。分享給大家供大家參考。具體如下:
用了我一個周末的時間,個中憤懣就不說了,就這個問題,我翻遍全球網絡沒有一篇像樣的資料,現在將實現原理簡單敘述如下:
調用WindowManager,并設置WindowManager.LayoutParams的相關屬性,通過WindowManager的addView方法創建View,這樣產生出來的View根據WindowManager.LayoutParams屬性不同,效果也就不同了。比如創建系統頂級窗口,實現懸浮窗口效果!
WindowManager的方法很簡單,基本用到的就三個addView,removeView,updateViewLayout。
而WindowManager.LayoutParams的屬性就多了,非常豐富,具體請查看SDK文檔。這里給出Android中的WindowManager.java源碼,可以具體看一下。
下面是簡單示例代碼:
public class myFloatView extends Activity {/** Called when the activity is first created. */@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);setContentView(R.layout.main);Button bb=new Button(getApplicationContext());WindowManager wm=(WindowManager)getApplicationContext().getSystemService("window");WindowManager.LayoutParams wmParams = new WindowManager.LayoutParams(); /** *以下都是WindowManager.LayoutParams的相關屬性 * 具體用途請參考SDK文檔 */wmParams.type=2002; //這里是關鍵,你也可以試試2003wmParams.format=1; /** *這里的flags也很關鍵 *代碼實際是wmParams.flags |= FLAG_NOT_FOCUSABLE; *40的由來是wmParams的默認屬性(32)+ FLAG_NOT_FOCUSABLE(8) */wmParams.flags=40;wmParams.width=40;wmParams.height=40;wm.addView(bb, wmParams);//創建View}}
別忘了在AndroidManifest.xml中添加權限:
PS:這里舉例說明一下type的值的意思:
/** * 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;
這個FIRST_SYSTEM_WINDOW的值就是2000。2003和2002的區別就在于2003類型的View比2002類型的還要top,能顯示在系統下拉狀態欄之上!
希望本文所述對大家的Android程序設計有所幫助。
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