相关:Service中创建窗口显示(TYPE_SYSTEM_ALERT, TYPE_SYSTEM_OVERLAY)
请求权限:
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"></uses-permission>
设置
dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);//这里设置的可以在桌面中显示对话框
转自:http://blog.csdn.net/rodulf/article/details/51550416