I am having problems establishing connection to the HIVEMQ broker.
Initially, just trying to initiate a connection .
I am using the Flutter pub package ‘mqtt_client’
I have tried to follow the video and the github example but still not able to establish connection
Be great if the HIVEMQ team could provide an updated "cookbook’ recipe using Flutter and the ‘mqtt_client’ package to connect, sub/pub to HIVEMQ. This would be a huge help to the entire development community.
import ‘package:flutter/material.dart’;
import ‘package:mqtt_client/mqtt_client.dart’ as mqtt;
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: ‘MQTT Demo’,
home: const MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});
@override
State createState() => _MyHomePageState();
}
class _MyHomePageState extends State {
String broker = ‘b20661310cc048cfb9583aac0be45323.s1.eu.hivemq.cloud’;
int port = 8883;
String username = ‘myUsername’;
String passwd = ‘myPassword’;
String clientIdentifier = ‘myId’;
late mqtt.MqttClient client;
// mqtt.MqttConnectionState connectionState;
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
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(‘MQTT Cient Test’),
),
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: [
const Text(
‘MQTT Client’,
),
TextButton(onPressed: () {
_connect();
},
child: Text(
‘Connect’
),)
],
),
),
);
}
}
void _connect() async {
/// First create a client, the client is constructed with a broker name, client identifier
/// and port if needed. The client identifier (short ClientId) is an identifier of each MQTT
/// client connecting to a MQTT broker. As the word identifier already suggests, it should be unique per broker.
/// The broker uses it for identifying the client and the current state of the client. If you don’t need a state
/// to be hold by the broker, in MQTT 3.1.1 you can set an empty ClientId, which results in a connection without any state.
/// A condition is that clean session connect flag is true, otherwise the connection will be rejected.
/// The client identifier can be a maximum length of 23 characters. If a port is not specified the standard port
/// of 1883 is used.
/// If you want to use websockets rather than TCP see below.
///
var client = mqtt.MqttClient(‘b20661310cc048cfb9583aac0be45323.s1.eu.hivemq.cloud’, ‘’);
client.port = 1883;
/// A websocket URL must start with ws:// or wss:// or Dart will throw an exception, consult your websocket MQTT broker
/// for details.
/// To use websockets add the following lines -:
/// client.useWebSocket = true;
/// client.port = 80; ( or whatever your WS port is)
/// Note do not set the secure flag if you are using wss, the secure flags is for TCP sockets only.
/// Set logging on if needed, defaults to off
client.logging(on: true);
/// If you intend to use a keep alive value in your connect message that is not the default(60s)
/// you must set it here
client.keepAlivePeriod = 30;
/// Add the unsolicited disconnection callback
// client.onDisconnected = _onDisconnected;
/// Connect the client, any errors here are communicated by raising of the appropriate exception. Note
/// in some circumstances the broker will just disconnect us, see the spec about this, we however will
/// never send malformed messages.
try {
await client.connect(‘username’,‘myPassword’);
} catch (e) {
print(e);
// _disconnect();
}
}
