I want to create a custom application that is stored at a system level and should display information or a floating dialog box all the time (based on the application logic I code) The app should be visible even if the SystemUser switches his profile.
This could be your starting point - https://cs.android.com/android/platform/superproject/main/+/main:frameworks/base/services/core/java/com/android/server/am/UserController.java;l=173?q=Usercontroller&sq=&ss=android%2Fplatform%2Fsuperproject%2Fmain
My Progress - I've created an application that has this floating widget & is stored as System App.
I've been finding way to do achieve it or modifying the UserSwitchingDialog that system shows and modify it based on my needs.