import 'dart:async'; import 'package:flutter/material.dart'; import 'package:roslibdart/roslibdart.dart'; void main() { runApp(const MyApp()); } class MyApp extends StatelessWidget { const MyApp({Key? key}) : super(key: key); // This widget is the root of your application. @override Widget build(BuildContext context) { return MaterialApp( title: 'Roslibdart Publisher Example', theme: ThemeData( primarySwatch: Colors.blue, ), home: const MyHomePage(title: 'Roslibdart Publisher Example'), ); } } class MyHomePage extends StatefulWidget { const MyHomePage({Key? key, required this.title}) : super(key: key); final String title; @override State createState() => _MyHomePageState(); } class _MyHomePageState extends State { late Ros ros; late Topic chatter; @override void initState() { ros = Ros(url: 'ws://127.0.0.1:9090'); chatter = Topic( ros: ros, name: '/topic', type: "std_msgs/String", reconnectOnClose: true, queueLength: 10, queueSize: 10); super.initState(); ros.connect(); Timer.periodic(const Duration(seconds: 3), (timer) async { msgToPublished++; Map json = {"data": msgToPublished.toString()}; await chatter.publish(json); setState(() {}); }); } int msgToPublished = 0; void initConnection() async { setState(() {}); } void destroyConnection() async { await ros.close(); setState(() {}); } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( // Here we take the value from the MyHomePage object that was created by // the App.build method, and use it to set our appbar title. title: Text(widget.title), ), body: Center( // Center is a layout widget. It takes a single child and positions it // in the middle of the parent. child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Text(msgToPublished.toString() + ' published'), ], ), ), ); } }