This app is intended for dual SIM Samsung phones: it won't (probably) work on different brands and will be useless on single SIM phones.
The two features of the app are:
- schedule an alarm that reminds you to enable or disable work SIM at shceduled times (for example at 9am when you go to work and at 6pm when you go home)
- a widget lets you open Dual SIM settings directly from the home screen
Currently supported phones:
- Huawei P9, Mate 10 Pro (and probably all other Huawei/Honor phones)
- Samsung S4 mini (and probably all other Samsung phones)
- ZTE Blade S6 (and probably all other ZTE and Nubia phones)
You can find a compiled and ready-to-use version on the app on the Play Store: https://play.google.com/store/apps/details?id=it.mauriziopinotti.dualsimwidget