How to display fullscreen apps when WindowManager.LayoutParams.TYPE changed from STATUS_BAR to SYSTEM_OVERLAY

I'm trying to modify an user interface by alter status bar. In order to make it overlap with apps, I changed the WindowManager.LayoutParams.TYPE from STATUS_BAR to OVERLAY. The background of status bar is now transparent. Thus there's no obvious side line in the whole scene. B开发者_运维知识库ut after changing, the FULLSCREEN doesn't work. Is there any way to solve this?

Thanks in advance.