myhomie_app/lib/Screens/Debug/DebugPage.dart

import 'package:flutter/material.dart';
import 'package:myhomie_app/Helpers/MQTTHelper.dart';
import 'package:myhomie_app/app_context.dart';
import 'package:provider/provider.dart';

class DebugPage extends StatefulWidget {
  DebugPage({Key key}) : super(key: key);

  @override
  _DebugPageState createState() => _DebugPageState();
}

class _DebugPageState extends State<DebugPage> {

  @override
  Widget build(BuildContext context) {
    final appContext = Provider.of<AppContext>(context);
    String lastMessage = "test";

    //lastMessage = MQTTHelper.instance.getLastMessage() == null ? "rien" : MQTTHelper.instance.getLastMessage();

    return Scaffold(
      appBar: AppBar(
        title: Text("Debug TODO"),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              "Last Message",
            ),
            Text(
              MQTTHelper.instance.getLastMessage() == null ? "rien" : MQTTHelper.instance.getLastMessage(),
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => {},
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}