Is it possible to lock fullscreen on Android? Basically hide toasts, hide home/back/switch, hide notification bar, make it so swiping from bottom or top doesn\'t work.
Depending on the version of Android you're targeting you could use Screen Pinning.
From Android Documentation (https://developer.android.com/about/versions/android-5.0.html):
Screen pinning
Android 5.0 introduces a new screen pinning API that lets you temporarily restrict users from leaving your task or being interrupted by notifications. This could be used, for example, if you are developing an education app to support high stakes assessment requirements on Android, or a single-purpose or kiosk application. Once your app activates screen pinning, users cannot see notifications, access other apps, or return to the home screen, until your app exits the mode.
There are two ways to activate screen pinning:
When task locking is active, the following behavior happens:
One way to do it is to use an overlay which requires SYSTEM_ALERT_WINDOW permission, while setting up the app with/as a service. See the prior answer with code example by yoah at Disable home button in android toddler app?