SystemChrome.setEnabledSystemUIOverlays([])
should do what you want.
You can bring it back with SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values)
.
Import it using
import 'package:flutter/services.dart';
Update answer (from Flutter 2.5 or latest):
SystemChrome.setEnabledSystemUIMode(SystemUiMode.leanBack);
Or you can use another options like:
SystemChrome.setEnabledSystemUIMode(SystemUiMode.manual, overlays: [
SystemUiOverlay.bottom
]); // to hide only bottom bar
Then when you need to re-show it (like when dispose) use this:
@override
void dispose() {
super.dispose();
SystemChrome.setEnabledSystemUIMode(SystemUiMode.manual, overlays: SystemUiOverlay.values); // to re-show bars
}