There are 2 repositories under systemui topic.
Replacement/extension for the stock Android System UI Tuner.
Helper for dealing with Android System UI visibility
A custom SystemUI Android Application that shows screen decoration windows across other android apps.
Control Android's Demo Mode from your app.
管理System UI,显示与隐藏Navigation bar和Status bar。
lightweight ROM for S4 LTE based on latest official Samsung binaries, with the focus on speed and small memory footprint
对StatusBar和NavigationBar进行着色的工具类,有注释[DEPRECATED] Apply background tinting to the Android system UI when using KitKat translucent modes
How to show/hide status bar and navigation bar ?
Customizing android navigation bar - System UI