Soft Keys - More Settings

激活屏幕上的按键，尽情享受吧！不需要根。

Activate the on-screen keys, enjoy it! Don't need root.

simple and easy to use version here :

https://play.google.com/store/apps/details?id=com.dogusumit.softkeys2

source codes here :

https://github.com/dogusumit/SoftKeys-MoreSettings

This app uses Accessibility services.