PubSub

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

var pubSubMessageListener =
  PubSubMessageListener { message ->
    // Logs new message
    Log.v("New Message Received", "Message : " + message.message)
  }

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

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

  // Logs persisted message list
  for (message in pubSubMessageList) {
    Log.v("Message List: ", "Message : " + message.message)
  }
}

Java

PubSubMessageListener pubSubMessageListener = new PubSubMessageListener() {
  @Override
  public void onMessageReceived(PubSubMessage message) {
    // Logs new message
    Log.v("New Message Received", "Message : " + message.getMessage());
  }
};

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

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

  // Logs persisted message list
  for(PubSubMessage message : pubSubMessageList){
    Log.v("Message List: ", "Message : " + message.getMessage());
  }
}

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
    var pubSubMessageListener =
      PubSubMessageListener { message ->
        // Logs new message
        Log.v("New Message Received", "Message : " + message.message)
    }

    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)
         * (this.application as MainApplication).meeting = meeting
        */

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

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

        for (message in pubSubMessageList) {
          // Logs persisted messages
           Log.v("Message List: ", "Message : " + message.message)
        }

        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
    private PubSubMessageListener pubSubMessageListener = new PubSubMessageListener() {
      @Override
      public void onMessageReceived(PubSubMessage message) {
          // Logs new message
          Log.v("New Message Received : ", "Message : " + message.getMessage());
      }
    };

    @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);
         * ((MainApplication) this.getApplication()).setMeeting(meeting);
        */

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

        // Subscribe for 'CHAT' topic
        List<PubSubMessage> pubSubMessageList = meeting.pubSub.subscribe("CHAT", pubSubMessageListener);
        for(PubSubMessage message : pubSubMessageList){
            // Logs persisted messages
            Log.v("Message List : ", "Message : " + message.getMessage());
        }

        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();
    }
}