MQTT: Android Client Example

settings.gradle

pluginManagement {
    repositories {
        gradlePluginPortal()
        google()
        mavenCentral()
        maven {
            url "https://repo.eclipse.org/content/repositories/paho-releases/"
        }
    }
}
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
        mavenCentral()
        maven {
            url "https://repo.eclipse.org/content/repositories/paho-releases/"
        }
    }
}
rootProject.name = "ITTSPahoMQTT"
include ':app'

build.gradle :app

dependencies { 
    .....
    implementation('org.eclipse.paho:org.eclipse.paho.android.service:1.0.2') {
        exclude module: 'support-v4'
    }
    implementation 'androidx.localbroadcastmanager:localbroadcastmanager:1.0.0'
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="itts.onno.ittspahomqtt">

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

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

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="236dp"
        android:onClick="published"
        android:text="PUBLISH"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 

    <TextView
        android:id="@+id/subText"
        android:layout_width="141dp"
        android:layout_height="68dp"
        android:layout_marginTop="360dp"
        android:text="TextView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 

    <Button
        android:id="@+id/connBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="524dp"
        android:onClick="conn"
        android:text="connect"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.201"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 

    <Button
        android:id="@+id/disconnBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="524dp"
        android:onClick="disconn"
        android:text="disconnect"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.78"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package itts.onno.ittspahomqtt;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class MainActivity extends AppCompatActivity {

    MqttAndroidClient client;
    TextView subText; 

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main); 

        subText = (TextView)findViewById(R.id.subText);

        String clientId = MqttClient.generateClientId();
        // client = new MqttAndroidClient(this.getApplicationContext(), "tcp://broker.mqttdashboard.com:1883",clientId);
        client = new MqttAndroidClient(this.getApplicationContext(), "tcp://192.168.0.111:1883",clientId);

//* -------------- masalah membuat aplikasi crash ------------------------
        try {
            IMqttToken token = client.connect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"connected!!",Toast.LENGTH_LONG).show();
                    setSubscription();
               }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"connection failed!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }

//* ---------------------------------------------------------------------------

        client.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable cause) {
            }
            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                subText.setText(new String(message.getPayload()));
            }
            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {
            }
        });
    }


    public void published(View v){

        String topic = "event";
        String message = "the payload";
        try {
            client.publish(topic, message.getBytes(),0,false);
            Toast.makeText(this,"Published Message",Toast.LENGTH_SHORT).show();
        } catch ( MqttException e) {
            e.printStackTrace();
        }
    } 

    private void setSubscription(){ 
        try{
            client.subscribe("event",0);
        }catch (MqttException e){
            e.printStackTrace();
        }
    }

    public void conn(View v){
        try {
            IMqttToken token = client.connect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"connected!!",Toast.LENGTH_LONG).show();
                    setSubscription(); 
                }
                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"connection failed!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    public void disconn(View v){
         try {
            IMqttToken token = client.disconnect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"Disconnected!!",Toast.LENGTH_LONG).show();
                }
                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"Could not diconnect!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }
}

Referensi

• https://people.utm.my/shaharil/mqtt-android-studio/