PubSub - Android

PubSub feature allows the participant to send and receive messages of the topics which he has subscribed.

Methods

publish()

This method is use for publishing message of specific topic.

Syntax

public void publish(String topic, String message, PubSubPublishOptions options)

Parameter Name	Type	Description
topic	String	This should be the topic for which you are publishing a message.
message	String	This is the actual message, which will be published to participants, who had subscribed to a particular topic.
options	PubSubPublishOptions	This is an object of PubSubPublishOptions, which provides an option, such as persist, which persists message history for upcoming participants.

Example

Kotlin

private fun sendMessage() {
  val options = PubSubPublishOptions()
  options.isPersist = true
  meeting!!.pubSub.publish("CHAT", "Hello from Android", options)
}

Java

protected void sendMessage() {
  PubSubPublishOptions options = new PubSubPublishOptions();
  options.setPersist(true);
  meeting.pubSub.publish("CHAT", "Hello from Android", options);
}

subscribe()

This method is used to subscribe for particular topic. This method returns a list of messages which were sent earlier.

Syntax

public List<PubSubMessage> subscribe(String topic, PubSubMessageListener listener)

Parameter Name	Type	Description
topic	String	This should be the topic to be subscribed.
listener	PubSubMessageListener	This is an object of PubSubMessageListener, which listens for upcoming messages and calls onMessageReceived function, when new message received.

Example

Kotlin

val pubSubMessageListener = object : PubSubMessageListener {
    override fun onMessageReceived(message: PubSubMessage) {
        Log.d("#message", "onMessageReceived: ${message.message}")
    }
    override fun onOldMessagesReceived(messages: List<PubSubMessage>) {
        // Persisted message list
        Log.d("#message", "onOldMessagesReceived: $messages")
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
  //...
  
  // Subscribe for 'CHAT' topic
  meeting!!.pubSub.subscribe("CHAT", pubSubMessageListener)

}

Java

PubSubMessageListener pubSubMessageListener = new PubSubMessageListener() {
    @Override
    public void onMessageReceived(PubSubMessage message) {
        Log.d("#message", "onMessageReceived: " + message.getMessage());
    }
    
    @Override
      public void onOldMessagesReceived(List<PubSubMessage> messages) {
      // Persisted message list
      Log.d("#message", "onOldMessagesReceived: " + messages);
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
  //...

  // Subscribe for 'CHAT' topic
  meeting.pubSub.subscribe("CHAT",pubSubMessageListener);

}

unsubscribe()

This method is used to unsubscribe the message topic.

Syntax

public void unsubscribe(String topic, PubSubMessageListener listener)

Parameter Name	Type	Description
topic	String	This should be the topic to be unsubscribed.
listener	PubSubMessageListener	This is an object of PubSubMessageListener, which was passed in subscribe().

Example

Kotlin

fun unsubscribe() {
  // Unsubscribe 'CHAT' topic
  meeting!!.pubSub.unsubscribe("CHAT", pubSubMessageListener)
}

Java

public void unsubscribe(){
  // Unsubscribe 'CHAT' topic
  meeting.pubSub.unsubscribe("CHAT", pubSubMessageListener);
}

Sample Code

Kotlin

package live.videosdk.rtc.android.kotlin

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.EditText
import android.widget.Toast
import androidx.appcompat.widget.Toolbar
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import live.videosdk.rtc.android.Meeting
import live.videosdk.rtc.android.listeners.PubSubMessageListener
import live.videosdk.rtc.android.model.PubSubPublishOptions

class ChatActivity : AppCompatActivity() {

    // Meeting
    var meeting: Meeting? = null

    // PubSubMessageListener
        val pubSubMessageListener = object : PubSubMessageListener {
        override fun onMessageReceived(message: PubSubMessage) {
            Log.d("#message", "onMessageReceived: ${message.message}")
        }
        override fun onOldMessagesReceived(messages: List<PubSubMessage>) {
            // Persisted message list
            Log.d("#message", "onOldMessagesReceived: $messages")
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_chat)

        /**
         * Here, we have created 'MainApplication' class, which extends android.app.Application class.
         * It has Meeting property and getter and setter methods of Meeting property.
         * In your android manifest, you must declare the class implementing android.app.Application (add the android:name=".MainApplication" attribute to the existing application tag):
         * In MainActivity.kt, we have set Meeting property.
         *
         * For Example: (MainActivity.kt)
         * var meeting = VideoSDK.initMeeting(context, meetingId, ParticipantName, micEnabled, webcamEnabled, paricipantId, mode, customTrack, metaData,signalingBaseUrl,preferredProtocol)
         * (this.application as MainApplication).meeting = meeting
        */

        // Get Meeting
        meeting = (this.application as MainApplication).meeting

        // Subscribe for 'CHAT' topic
        meeting!!.pubSub.subscribe("CHAT", pubSubMessageListener)

        sendMessage()
    }

    private fun sendMessage() {
      val options = PubSubPublishOptions()
      options.isPersist = true
      meeting!!.pubSub.publish("CHAT", "Hello from Android", options)
    }

    override fun onDestroy() {
      // Unsubscribe for 'CHAT' topic
      meeting!!.pubSub.unsubscribe("CHAT", pubSubMessageListener)
      super.onDestroy()
    }
}

Java

package live.videosdk.rtc.android.java;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import java.util.List;
import live.videosdk.rtc.android.Meeting;
import live.videosdk.rtc.android.lib.PubSubMessage;
import live.videosdk.rtc.android.listeners.PubSubMessageListener;
import live.videosdk.rtc.android.model.PubSubPublishOptions;

public class ChatActivity extends AppCompatActivity {

    // Meeting
    Meeting meeting;

    // PubSubMessageListener
    PubSubMessageListener pubSubMessageListener = new PubSubMessageListener() {
        @Override
        public void onMessageReceived(PubSubMessage message) {
            Log.d("#message", "onMessageReceived: " + message.getMessage());
        }
        
        @Override
          public void onOldMessagesReceived(List<PubSubMessage> messages) {
          // Persisted message list
          Log.d("#message", "onOldMessagesReceived: " + messages);
        }
    };

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

        /**
         * Here, we have created 'MainApplication' class, which extends android.app.Application class.
         * It has Meeting property and getter and setter methods of Meeting property.
         * In your android manifest, you must declare the class implementing android.app.Application (add the android:name=".MainApplication" attribute to the existing application tag):
         * In MainActivity.java, we have set Meeting property.
         *
         * For Example: (MainActivity.java)
         * Meeting meeting = VideoSDK.initMeeting(context, meetingId, ParticipantName, micEnabled, webcamEnabled, participantId, mode, customTrack, metaData, signalingBaseUrl,preferredProtocol);
         * ((MainApplication) this.getApplication()).setMeeting(meeting);
        */

        // Get Meeting
        meeting = ((MainApplication) this.getApplication()).getMeeting();

        // Subscribe for 'CHAT' topic
        List<PubSubMessage> pubSubMessageList = meeting.pubSub.subscribe("CHAT", pubSubMessageListener);

        sendMessage();
    }

    protected void sendMessage() {
      PubSubPublishOptions publishOptions = new PubSubPublishOptions();
      publishOptions.setPersist(true);
      meeting.pubSub.publish("CHAT", "Hello from Android", publishOptions);
    }

    @Override
    protected void onDestroy() {
      // Unsubscribe for 'CHAT' topic
      meeting.pubSub.unsubscribe("CHAT", pubSubMessageListener);
      super.onDestroy();
    }
}