lunasea/lib/core/ui/will_pop_scope.dart

import 'package:flutter/material.dart';

class LunaWillPopScope extends WillPopScope {
    LunaWillPopScope({
        @required GlobalKey<ScaffoldState> scaffoldKey,
        @required Widget child,
    }) : super(
        onWillPop: () async {
            if(scaffoldKey?.currentState?.hasDrawer ?? false) {
                if(scaffoldKey?.currentState?.isDrawerOpen ?? false) return true;
                scaffoldKey?.currentState?.openDrawer();
                return false;
            }
            return true;
        },
        child: child,
    );
}