flutter_app/lib/views/doublecolview.dart

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
import '../main.dart';
import '../model.dart';
import '../settings.dart';
import 'contactsview.dart';
import 'messageview.dart';

class DoubleColumnView extends StatefulWidget {
  @override
  _DoubleColumnViewState createState() => _DoubleColumnViewState();
}

class _DoubleColumnViewState extends State<DoubleColumnView> {
  @override
  Widget build(BuildContext context) {
    var flwtch = Provider.of<AppState>(context);
    var cols = Provider.of<Settings>(context).uiColumns(true);
    return Flex(
      direction: Axis.horizontal,
      children: <Widget>[
        Flexible(
          flex: cols[0],
          child: ContactsView(
            key: widget.key,
          ),
        ),
        Flexible(
          flex: cols[1],
          child: flwtch.selectedConversation == null
              ? Card(child:Center(child: Text(AppLocalizations.of(context)!.addContactFirst)))
              : //dev
              MultiProvider(providers: [
                  ChangeNotifierProvider.value(value: Provider.of<ProfileInfoState>(context)),
                  ChangeNotifierProvider.value(value: Provider.of<ProfileInfoState>(context).contactList.getContact(flwtch.selectedConversation!)!),
                ], child: Container(child: MessageView())),
        ),
      ],
    );
  }
}