Android中懸浮窗口的實現原理和示例代碼

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;   //這裏是關鍵，你也可以試試2003
        wmParams.format=1;
         /**
         *這裏的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
    }
}

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

        /**
         * 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;