(3) Aplicación MQTT en Android

Prefacio

Hemos construido y probado el servidor Broker de MQTT.fx, y ahora queremos usar el punto de cliente de Android para comunicarnos con el servidor.
Una biblioteca existente para comunicarse con Android es Paho Android Service.

Paho Android Service es un paquete de servicio de cliente MQTT desarrollado en base a la biblioteca Paho MQTT del lenguaje Java.

Acceso

• Agregar la dirección del almacén en build.gradle

maven {
     url "https://repo.eclipse.org/content/repositories/paho-snapshots/"
}
或者是
maven {
     url "https://repo.eclipse.org/content/repositories/paho-releases/"
}

• Introducir dependencias en la aplicación o submódulo

dependencies {
    implementation 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.1.0'
    implementation 'org.eclipse.paho:org.eclipse.paho.android.service:1.1.1'
}

• Agregue permisos y registre el servicio en el archivo AndroidManifest

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="xxx.xxxx.mqtt">

    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

    <application>
        <service android:name="org.eclipse.paho.android.service.MqttService" />
    </application>

</manifest>

solicitud

• El siguiente es el código de establecimiento y suscripción.

public class IOT {
    private final String TAG = "MyIOT";

    private Context mContext;

    /* 用于上报消息 */
    final private String PUB_TOPIC = "/message/publish";
    /* 用于接受消息 */
    final private String SUB_TOPIC = "/message/publish";
    /* 自己部署到本地的服务器地址（协议+地址+端口号） */
    private final String HOST = "tcp://替换成自己的IP:1883";
    /* 用户名 */
    private String USERNAME = "admin";
    /* 密码 */
    private String PASSWORD = "admin";

    private MqttAndroidClient mqttAndroidClient;

    private static final class IOTHolder {
        private static final IOT instance = new IOT();
    }

    public static IOT getInstance() {
        return IOT.IOTHolder.instance;
    }

    /**
     * 初始化
     *
     * @param context
     */
    public void init(Context context) {
        mContext = context.getApplicationContext();
        connect();
    }

    /**
     * 订阅特定的主题
     *
     * @param topic mqtt主题
     */
    public void subscribeTopic(String topic) {
        try {
            mqttAndroidClient.subscribe(topic, 0, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Log.i(TAG, "subscribed succeed");
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Log.i(TAG, "subscribed failed");
                }
            });

        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    /**
     * 向默认的主题/user/update发布消息
     *
     * @param payload 消息载荷
     */
    public void publishMessage(String payload) {
        try {
            if (!mqttAndroidClient.isConnected()) {
                mqttAndroidClient.connect();
            }
            MqttMessage message = new MqttMessage();
            message.setPayload(payload.getBytes());
            message.setQos(0);
            mqttAndroidClient.publish(PUB_TOPIC, message, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Log.i(TAG, "publish succeed!");
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Log.i(TAG, "publish failed!");
                }
            });
        } catch (MqttException e) {
            Log.e(TAG, e.toString());
            e.printStackTrace();
        }
    }

    /**
     * 断开连接销毁资源
     */
    public void destroy() {
        try {
            if (mqttAndroidClient.isConnected()) {
                mqttAndroidClient.disconnect();
                mqttAndroidClient.unregisterResources();
            }
            mqttAndroidClient = null;
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    /**
     * 断开连接
     */
    public void disconnect() {
        try {
            if (mqttAndroidClient.isConnected()) {
                mqttAndroidClient.disconnect();
            }
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    /**
     * 重新连接
     */
    public void reInit() {
        connect();
    }


    /**
     * 连接
     */
    private void connect() {
        if (mqttAndroidClient != null && mqttAndroidClient.isConnected()) return;

        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName(USERNAME);
        mqttConnectOptions.setPassword(PASSWORD.toCharArray());
        mqttConnectOptions.setCleanSession(false); // 不清理离线消息。qos=1的消息，在设备离线期间会保存在云端。
        mqttConnectOptions.setAutomaticReconnect(false); //本demo关闭自动重连。强烈建议生产环境开启自动重连。
        mqttConnectOptions.setKeepAliveInterval(300);
        /* 创建MqttAndroidClient对象, 并设置回调接口 */
        mqttAndroidClient = new MqttAndroidClient(mContext, HOST, DeviceUuidFactory2.getDeviceUuidStr(mContext));
        mqttAndroidClient.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable cause) {
                Log.i(TAG, "connection lost");
            }

            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                Log.i(TAG, "topic: " + topic + ", msg: " + new String(message.getPayload()));
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {
                Log.i(TAG, "msg delivered");
            }
        });
        /* Mqtt建连 */
        try {
            mqttAndroidClient.connect(mqttConnectOptions, null, new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Log.i(TAG, "connect succeed");

                    //自动订阅
                    subscribeTopic(SUB_TOPIC);
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Log.i(TAG, "connect failed");
                }
            });

        } catch (MqttException e) {
            e.printStackTrace();
        }

    }

dirección de github

Alibaba Cloud MQTT utiliza el acceso Paho