Raise Hand using PubSub - Android

Let us see, how we can use PubSub to implement Raise Hand functionality. If you are not familiar with the PubSub mechanism and pubSub class, you can follow this guide.

Implementing Raise Hand

1. First step in raise hand is choosing the topic which all the participants will publish and subscribe to know some participant raise their hand. We will be using RAISE_HAND as the topic for this one.
2. On the raiseHand button, publish any message to that specific topic.

Kotlin

class MainActivity : AppCompatActivity() {

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

    //...

    findViewById(R.id.btnRaiseHand).setOnClickListener(view -> sendRaiseHandMessage());
  }

  private fun sendRaiseHandMessage() {
    val publishOptions = PubSubPublishOptions()
    publishOptions.setPersist(false)

    // Sending the Message using the publish method
    meeting!!.pubSub.publish("RAISE_HAND", "Raise Hand", publishOptions)
  }
}

Java

public class MainActivity extends AppCompatActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_chat);

    //...

    findViewById(R.id.btnRaiseHand).setOnClickListener(view -> sendRaiseHandMessage());
  }

  private void sendRaiseHandMessage()
  {
    PubSubPublishOptions publishOptions = new PubSubPublishOptions();
    publishOptions.setPersist(false);

    // Sending the Message using the publish method
    meeting.pubSub.publish("RAISE_HAND", "Raise Hand", publishOptions);
  }
}

3. Now let us show an alert to all the participants showing who raised the hand.

Kotlin

class MainActivity : AppCompatActivity() {

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

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

    //...

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

Java

public class MainActivity extends AppCompatActivity {

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

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

    //..

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

API Reference

The API references for all the methods and events utilised in this guide are provided below.

• pubSub()