What happens when Android app goes to background?

How to change the wallpaper on an Android device

Foreground refers to the active apps which consume data and are currently running on the mobile. Background refers to the data used when the app is doing some activity in the background, which is not active right now .

Open the Settings option on the phone. Look for the section called “Application Manager” or simply “Apps”. On some other phones, go to Settings > General > Apps. Go to the “All apps” tab, scroll to the application(s) that’s running, and open it.

When an App is put on background and then resumed, it resumes the specific Activity it was in before going to background . This means that you would need to implement whatever you want done on resuming from background in all Activity of your Application.