How to hide the Android Status Bar in a Flutter App?
You can use SystemChrome.setEnabledSystemUIOverlays([]) to hide and SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values) to bring it back again.
However, there will be slight grey area and there is not fix for this as of right now. When status bar is hidden, app bar's height remains the same.
See the github issue: https://github.com/flutter/flutter/issues/14432