How to hide the Android Status Bar in a Flutter App?
SystemChrome.setEnabledSystemUIOverlays([]) should do what you want.
You can bring it back with SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values).
SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values)
Import it using
import 'package:flutter/services.dart';