Android Enthusiasts Stack Exchange is a question and answer site for enthusiasts and power users of the Android operating system. It only takes a minute to sign up.
Sign up to join this community
I want to take an old android phone and turn it into a dedicated calculator. In other words, I'd like to make it so I boot up the phone and my calculator app is running, and there is no way to access any other app, the home screen, app drawer, anything. No lock screen either. Just this app and the settings app, which there would be a shortcut too in this app.
Is this possible? Is android the best OS for this project? Is there an easy way to make this happen?
If you didn't have the requirement of being able to access the settings (the settings app is part of the launcher in some ROMs), this would probably be easier. In that case, you could simply build a custom ROM that boots straight to calculator. The main disadvantage would be the absence of even a battery indicator.
There is screen pinning in lollipop which you can access from the recent apps screen. This will keep the pinned app open. The home button will be disabled, no notifications will show, and the lock screen is bypassed. If you need to unpin the app, you hold the back and recent apps buttons for about a second.
You did mention this is an old android phone, which will most likely not have lollipop (Android 5.0+), so unless you can somehow update it or flash an updated ROM, then you can't use screen pinning.
