roslib_dart/example/subscriber/lib/main.dart
2022-02-22 21:54:27 +08:00

80 lines
1.8 KiB
Dart

import 'package:flutter/material.dart';
import 'package:roslibdart/roslibdart.dart';
import 'dart:async';
import 'dart:convert';
void main() {
runApp(const ExampleApp());
}
class ExampleApp extends StatelessWidget {
const ExampleApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return const MaterialApp(
title: 'Roslibdart subscriber Example',
home: HomePage(),
);
}
}
class HomePage extends StatefulWidget {
const HomePage({Key? key}) : super(key: key);
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
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(const Duration(seconds: 3), () async {
await chatter.subscribe(subscribeHandler);
// await chatter.subscribe();
});
}
void destroyConnection() async {
await chatter.unsubscribe();
await ros.close();
setState(() {});
}
String msgReceived = '';
Future<void> subscribeHandler(Map<String, dynamic> msg) async {
msgReceived = json.encode(msg);
setState(() {});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Roslibdart Subscriber Example'),
),
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: <Widget>[
Text(msgReceived + ' received'),
],
),
),
);
}
}