在Android上查看通知栏上方

Question

如何在通知栏上方添加视图？我在服务中使用：

windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

    chatHead = new ImageView(this);
    chatHead.setImageResource(R.drawable.bg1);
    chatHead.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
            | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
            | View.SYSTEM_UI_FLAG_IMMERSIVE);


    final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.FLAG_FULLSCREEN, 
            WindowManager.LayoutParams.FLAG_FULLSCREEN,                 
                        WindowManager.LayoutParams.TYPE_SYSTEM_ALERT,               
                        WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN,
                        PixelFormat.TRANSLUCENT);


    params.gravity = Gravity.TOP | Gravity.LEFT;
    params.x = 0;
    params.y = 100;

    windowManager.addView(chatHead, params);

但是视图仍在通知栏中。我知道它是可行的，因为NotifierPro可以做到这一点。但是如何？