Change Mode - Android

In a live stream, audience members usually join in RECV_ONLY mode, meaning they can only view and listen to the hosts. However, if a host invites an audience member to actively participate (e.g., to speak or present), the audience member can switch their mode to SEND_AND_RECV using the changeMode() method.

caution

changeMode() only ever changes the mode of the participant who calls it. There is no form of changeMode() that takes another participant's id, and a host cannot change an audience member's mode directly.

Promotion therefore takes two pieces of code, one on each side, and neither does anything on its own:

1. On the host — publish a request to the invited participant over PubSub. Step 1 and Step 2 below.
2. On the invited participant — subscribe to that same topic and, in the message handler, call changeMode() yourself. Step 3 below. Without this subscriber the request reaches nobody and no mode ever changes.

An implementation that only publishes the request looks finished and does nothing.

This guide explains how to use the changeMode() method and walks through a sample implementation where a host invites an audience member to become a host using PubSub.

changeMode()

• The changeMode() method from the Meeting class switches the calling participant's own mode during a live stream — for example, an audience member becoming a host.
• It takes only the target mode. To move a different participant between modes, send them a PubSub request and let their client call changeMode() itself, as shown in the Implementation Guide below.

Example: a participant changing its own mode

Kotlin

import live.videosdk.rtc.android.lib.MeetingMode

class LiveStreamActivity : AppCompatActivity() {
 override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_live_stream);
    // initialize the meeting
    liveStream = VideoSDK.initMeeting(... )
    ...

    // join meeting
    liveStream!!.join()

    // Button to change mode
    val changeModeBtn: Button = findViewById(R.id.btnChangeMode)
    changeModeBtn.setOnClickListener {
        liveStream.changeMode(MeetingMode.SEND_AND_RECV.name)
    }
  }
}

Java

import live.videosdk.rtc.android.lib.MeetingMode;

public class LiveStreamActivity extends AppCompatActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_live_stream);
    // initialize the meeting
    Meeting liveStream = VideoSDK.initMeeting( ...);
    ...

    // join meeting
    liveStream.join()  

    // Button to change mode
    Button changeModeBtn = findViewById(R.id.btnChangeMode);
    changeModeBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            liveStream.changeMode(MeetingMode.SEND_AND_RECV.name());
        }
    });
  
  }
}

Implementation Guide

Step 1 : Create a Pubsub Topic

• Set up a PubSub topic to send a mode change request from the host to a specific audience member.

Kotlin

fun sendInvite(livestream: Meeting, participantId: String) {
    val pubSubPublishOptions = PubSubPublishOptions().apply {
        isPersist = false
    }

    livestream.pubSub.publish(
        "REQUEST_TO_JOIN_AS_HOST_$participantId", // PubSub topic specific to participant
        "SEND_AND_RECV", // message
        pubSubPublishOptions
    )
}

Java

void sendInvite(Meeting livestream, String participantId) {
   PubSubPublishOptions pubSubPublishOptions = new PubSubPublishOptions(); 
   pubSubPublishOptions.setPersist(false);
   livestream.pubSub.publish(
        "REQUEST_TO_JOIN_AS_HOST_"+ participantId, // PubSub topic specific to participant
        "SEND_AND_RECV", // message
        pubSubPublishOptions
    );
}

Step 2 : Create an Invite Button

• Add an "Invite on Stage" button for each audience member. When clicked, it publishes a PubSub message with the mode "SEND_AND_RECV" to that participant.

Kotlin

// In ParticipantListAdapter.kt, inside showPopup method
if (participant!!.mode == "RECV_ONLY") {
    popup.menu.add("Add as a co-host")
    
    popup.setOnMenuItemClickListener { item: MenuItem ->
        if (item.toString() == "Add as a co-host") {
            sendInvite(liveStream,participantId);
            holder.requestedIndicator.visibility = View.VISIBLE
            holder.btnParticipantMoreOptions.isEnabled = false
            return@setOnMenuItemClickListener true
        }
        false
    }
}

Java

// In ParticipantListAdapter.java, inside showPopup method
if ("RECV_ONLY".equals(participant.getMode())) {
    popup.getMenu().add("Add as a co-host");

    popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            if ("Add as a co-host".equals(item.toString())) {
                sendInvite(liveStream,participantId);
                holder.requestedIndicator.setVisibility(View.VISIBLE);
                holder.btnParticipantMoreOptions.setEnabled(false);
                return true;
            }
            return false;
        }
    });
}

Step 3 : Create a Listener to Change the Mode

• On the audience side, subscribe to the specific PubSub topic. When a mode request is received, update the participant’s mode using changeMode().

Kotlin

// In your class where you define coHostListener
val coHostListener = object : PubSubMessageListener {
    override fun onMessage(pubSubMessage: PubSubMessage) {
        showCoHostRequestDialog()
    }
}

liveStream.pubSub.subscribe(
    "REQUEST_TO_JOIN_AS_HOST_${liveStream.localParticipant.id}", 
    coHostListener
)

// In the showCoHostRequestDialog method
private fun showCoHostRequestDialog() {
    // Dialog setup code...

    acceptBtn.setOnClickListener {
        liveStream.changeMode("SEND_AND_RECV")
    }
    // Rest of the dialog code...
}

Java

// In your class where you define coHostListener
PubSubMessageListener coHostListener = new PubSubMessageListener () {
    @Override
    public void onMessage(PubSubMessage pubSubMessage) {
        showCoHostRequestDialog();
    }
};

liveStream.pubSub.subscribe("REQUEST_TO_JOIN_AS_HOST_" + liveStream.getLocalParticipant().getId(), coHostListener);

// In the showCoHostRequestDialog method
private void showCoHostRequestDialog() {
    // Dialog setup code...

    acceptBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            liveStream.changeMode("SEND_AND_RECV");
        }
    });

    // Rest of the dialog code...
}

note

Calling changeMode() changes only the caller's mode. Every other client must rebuild its host and audience lists from the participant-mode-changed event, as described in Updating the UI on mode change.

Updating the UI on mode change

changeMode() updates the mode of the participant who calls it. The room then broadcasts a participant-mode-changed event to every participant, including clients that did not initiate the change. Each client should use that event to update its UI.

In the event handler, rebuild the lists that drive your UI by filtering participants by their current mode, then refresh the view. Simply pinning, unpinning, or displaying a message is not enough: when a participant is promoted, their mode changes, but other clients will not automatically move them from the audience to the stage.

meeting.addEventListener(object : MeetingEventListener() {
    override fun onParticipantModeChanged(data: JSONObject) {
        // Rebuild both lists from the current participant state, then refresh.
        speakers = participantsWithMode("SEND_AND_RECV")
        viewers  = participantsWithMode("SIGNALLING_ONLY")
        notifyDataSetChanged()
    }
})

caution

Rebuild both lists — the speakers and the viewers. Removing the participant from the audience list alone is the common half-fix: they disappear from the audience and never appear on stage.

API Reference

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

• changeMode()
• Participant
• Meeting
• pubSub()