Reactions

Add, remove, and manage emoji reactions on messages in your Android chat application

Quick Reference for AI Agents & Developers

Kotlin

// Add reaction
CometChat.addReaction(messageId, "😊", object : CallbackListener<BaseMessage>() {
    override fun onSuccess(message: BaseMessage) { }
    override fun onError(e: CometChatException) { }
})

// Remove reaction
CometChat.removeReaction(messageId, "😊", object : CallbackListener<BaseMessage>() {
    override fun onSuccess(message: BaseMessage) { }
    override fun onError(e: CometChatException) { }
})

// Fetch reactions for a message
val reactionRequest = ReactionRequest.ReactionRequestBuilder()
    .setMessageId(messageId)
    .setLimit(30)
    .build()
reactionRequest.fetchNext(callback)

// Listen for real-time reaction events
CometChat.addMessageListener(listenerID, object : MessageReactionListener {
    override fun onMessageReactionAdded(reaction: MessageReaction) { }
    override fun onMessageReactionRemoved(reaction: MessageReaction) { }
})

Java

// Add reaction
CometChat.addReaction(messageId, "😊", new CallbackListener<BaseMessage>() {
    @Override
    public void onSuccess(BaseMessage message) { }
    @Override
    public void onError(CometChatException e) { }
});

// Remove reaction
CometChat.removeReaction(messageId, "😊", new CallbackListener<BaseMessage>() {
    @Override
    public void onSuccess(BaseMessage message) { }
    @Override
    public void onError(CometChatException e) { }
});

// Fetch reactions for a message
ReactionRequest reactionRequest = new ReactionRequest.ReactionRequestBuilder()
    .setMessageId(messageId)
    .setLimit(30)
    .build();
reactionRequest.fetchNext(callback);

// Listen for real-time reaction events
CometChat.addMessageListener(listenerID, new MessageReactionListener() {
    @Override
    public void onMessageReactionAdded(MessageReaction reaction) { }
    @Override
    public void onMessageReactionRemoved(MessageReaction reaction) { }
});

Available via: SDK | REST API | UI Kits

Enhance user engagement in your chat application with message reactions. Users can express their emotions using reactions to messages. This feature allows users to add or remove reactions, and to fetch all reactions on a message. You can also listen to reaction events in real-time. Let’s see how to work with reactions in CometChat’s Android SDK.

Add a Reaction

Users can add a reaction to a message by calling addReaction with the message ID and the reaction emoji.

Java

int messageId = 1;
String emoji = "😊";

CometChat.addReaction(messageId, emoji, new CometChat.CallbackListener<BaseMessage>() {
  @Override
  public void onSuccess(BaseMessage message) {
      Log.e(TAG, "Reaction added: " + message.getReactions());
  }

  @Override
  public void onError(CometChatException e) {
      Log.e(TAG, "Failed to add reaction: " + e.getMessage());
  }
});

Kotlin

val messageId = 1
val emoji = "😊"

CometChat.addReaction(messageId, emoji, object : CometChat.CallbackListener<BaseMessage>() {
  override fun onSuccess(message: BaseMessage?) {
      Log.e(TAG, "Reaction added: ${message.reactions}")
  }

  override fun onError(e: CometChatException?) {
      Log.e(TAG, "Failed to add reaction: ${e?.message}")
  }
})

You can react on Text, Media and Custom messages. For more details on message types, see Message Structure & Hierarchy.

Remove a Reaction

Removing a reaction from a message can be done using the removeReaction method.

Java

int messageId = 1;
String emoji = "😊";

CometChat.removeReaction(messageId, emoji, new CometChat.CallbackListener<BaseMessage>() {
  @Override
  public void onSuccess(BaseMessage message) {
      Log.e(TAG, "Reaction removed: " + message.getReactions());
  }

  @Override
  public void onError(CometChatException e) {
      Log.e(TAG, "Failed to remove reaction: " + e.getMessage());
  }
});

Kotlin

val messageId = 1
val emoji = "😊"

CometChat.removeReaction(messageId, emoji, object : CometChat.CallbackListener<BaseMessage>() {
  override fun onSuccess(message: BaseMessage?) {
      Log.e(TAG, "Reaction removed: ${message.reactions}")
  }

  override fun onError(e: CometChatException?) {
      Log.e(TAG, "Failed to remove reaction: ${e?.message}")
  }
})

Fetch Reactions for a Message

To get all reactions for a specific message, first create a ReactionRequest using ReactionRequestBuilder. You can specify the number of reactions to fetch with setLimit with max limit 100. For this, you will require the ID of the message. This ID needs to be passed to the setMessageId() method of the builder class. The setReaction() will allow you to fetch details for specific reaction or emoji.

Setting	Description
setMessageId(int value)	Specifies the unique identifier of the message for which you want to fetch reactions. This parameter is mandatory as it tells the SDK which message’s reactions are being requested.
setReaction(String value)	Filters the reactions fetched by the specified reaction type (e.g., ”😊”, ”😂”, ”👍”). When set, this method will cause the ReactionRequest to only retrieve details of the provided reaction for the given message.

Fetch Next

The fetchNext() method fetches the next set of reactions for the message.

Java

int limit = 30;
int messageId = 1;

ReactionRequest reactionRequest = new ReactionRequest.ReactionRequestBuilder()
      .setLimit(30)
      .setMessageId(1)
      .build();

reactionRequest.fetchNext(new CometChat.CallbackListener<List<MessageReaction>>() {
  @Override
  public void onSuccess(List<MessageReaction> reactions) {
      Log.e(TAG, "Total Reactions: " + reactions.size());
      for (MessageReaction reaction : reactions) {
          Log.e(TAG, "Reaction: " + reaction.getReaction());
      }
  }

  @Override
  public void onError(CometChatException e) {
      Log.e(TAG, "Reaction fetch error: " + e.getMessage());
  }
});

Kotlin

val limit = 30
val messageId = 1

val reactionRequest = ReactionRequest.ReactionRequestBuilder()
      .setLimit(limit)
      .setMessageId(messageId)
      .build()

reactionRequest.fetchNext(object : CometChat.CallbackListener<List<MessageReaction>>() {
  override fun onSuccess(reactions: List<MessageReaction>?) {
      Log.e(TAG, "Total Reactions: ${reactions?.size}")
      reactions?.forEach { reaction ->
          Log.e(TAG, "Reaction: ${reaction.reaction}")
      }
  }

  override fun onError(e: CometChatException?) {
      Log.e(TAG, "Reaction fetch error: ${e?.message}")
  }
})

Fetch Previous

The fetchPrevious() method fetches the previous set of reactions for the message.

Java

int limit = 30;
int messageId = 1;

ReactionRequest reactionRequest = new ReactionRequest.ReactionRequestBuilder()
      .setLimit(30)
      .setMessageId(1)
      .build();

reactionRequest.fetchPrevious(new CometChat.CallbackListener<List<MessageReaction>>() {
  @Override
  public void onSuccess(List<MessageReaction> reactions) {
      Log.e(TAG, "Total Reactions: " + reactions.size());
      for (MessageReaction reaction : reactions) {
          Log.e(TAG, "Reaction: " + reaction.getReaction());
      }
  }

  @Override
  public void onError(CometChatException e) {
      Log.e(TAG, "Reaction fetch error: " + e.getMessage());
  }
}); 

Kotlin

val limit = 30
val messageId = 1

val reactionRequest = ReactionRequest.ReactionRequestBuilder()
      .setLimit(limit)
      .setMessageId(messageId)
      .build()

reactionRequest.fetchPrevious(object : CometChat.CallbackListener<List<MessageReaction>>() {
  override fun onSuccess(reactions: List<MessageReaction>?) {
      Log.e(TAG, "Total Reactions: ${reactions?.size}")
      reactions?.forEach { reaction ->
          Log.e(TAG, "Reaction: ${reaction.reaction}")
      }
  }

  override fun onError(e: CometChatException?) {
      Log.e(TAG, "Reaction fetch error: ${e?.message}")
  }
})

Real-time Reaction Events

Keep the chat interactive with real-time updates for reactions. Register a listener for these events and make your UI responsive. For more information on listeners, see Real-Time Listeners.

Java

private String listenerID = "UNIQUE_LISTENER_ID";

CometChat.addMessageListener(listenerID, new CometChat.MessageReactionListener() {
  @Override
  public void onMessageReactionAdded(MessageReaction reaction) {
      Log.e(TAG, "Reaction added");
  }

  @Override
  public void onMessageReactionRemoved(MessageReaction reaction) {
      Log.e(TAG, "Reaction removed");
  }
});

Kotlin

val listenerID = "UNIQUE_LISTENER_ID"

CometChat.addMessageListener(listenerID, object : CometChat.MessageReactionListener {
  override fun onMessageReactionAdded(reaction: MessageReaction?) {
      Log.e(TAG, "Reaction added")
  }

  override fun onMessageReactionRemoved(reaction: MessageReaction?) {
      Log.e(TAG, "Reaction removed")
  }
})

Removing a Reaction Listener

To stop listening for reaction events, remove the listener as follows:

Java

private String listenerID = "UNIQUE_LISTENER_ID";

CometChat.removeMessageListener(listenerID);

Kotlin

val listenerID = "UNIQUE_LISTENER_ID"

CometChat.removeMessageListener(listenerID)   

Always remove listeners when they’re no longer needed (e.g., in onDestroy() or when navigating away). Failing to remove listeners can cause memory leaks and duplicate event handling.

Get Reactions List

To retrieve the list of reactions reacted on particular message, you can use the message.getReactions() method. This method will return an array containing the reactions, or an empty array if no one reacted on the message.

Java

message.getReactions()

Kotlin

message.reactions 

Check if Logged-in User has Reacted on Message

To check if the logged-in user has reacted on a particular message or not, You can use the getReactedByMe() method on any ReactionCount object instance. This method will return a boolean value, true if the logged-in user has reacted on that message, otherwise false.

Java

for (ReactionCount reactionCount : message.getReactions()) {
  Log.e(TAG, "isReactedByMe" + reactionCount.getReactedByMe()); //Return true is logged-in user reacted on that message, otherwise false
}

Kotlin

for (reactionCount in message.reactions) {
  Log.e(TAG, "isReactedByMe" + reactionCount.reactedByMe) //Return true is logged-in user reacted on that message, otherwise false
}

Update Message With Reaction Info

When a user adds or removes a reaction, you will receive a real-time event. Once you receive the real time event you would want to update the message with the latest reaction information. To do so you can use the updateMessageWithReactionInfo() method.

The updateMessageWithReactionInfo() method provides a seamless way to update the reactions on a message instance (BaseMessage) in real-time. This method ensures that when a reaction is added or removed from a message, the BaseMessage object’s getReactions() property reflects this change immediately.

When you receive a real-time reaction event (MessageReaction), call the updateMessageWithReactionInfo() method, passing the BaseMessage instance (message), event data (MessageReaction) and reaction event action type (CometChatConstants.REACTION_ADDED or CometChatConstants.REACTION_REMOVED) that corresponds to the message being reacted to.

Java

// The message to which the reaction is related
BaseMessage message = ...;

// The reaction event data received in real-time
MessageReaction messageReaction = ...;

// The recieved reaction event real-time action type. Can be CometChatConstants.REACTION_ADDED or CometChatConstants.REACTION_REMOVED
String action = CometChatConstants.REACTION_ADDED;

BaseMessage modifiedBaseMessage = CometChatHelper.updateMessageWithReactionInfo(
baseMessage, 
messageReaction, 
action
);

Kotlin

// The message to which the reaction is related
val message: BaseMessage = ...

// The reaction event data received in real-time
val messageReaction: MessageReaction = ...

// The recieved reaction event real-time action type. Can be CometChatConstants.REACTION_ADDED or CometChatConstants.REACTION_REMOVED
val action = CometChatConstants.REACTION_ADDED

// Update the BaseMessage instance with the new reaction information
val modifiedBaseMessage: BaseMessage = CometChatHelper.updateMessageWithReactionInfo(
  message, 
  messageReaction, 
  action
)

After calling this method, the message instance’s reactions are updated. You can then use message.getReactions() to get the latest reactions and refresh your UI accordingly.

Best Practices

Limit Reaction Types

Define a specific set of allowed emoji reactions in your app to maintain consistency and prevent inappropriate reactions. Consider using a reaction picker UI component with predefined options.

Update UI Optimistically

Update your UI immediately when a user adds or removes a reaction, then handle the server response. This provides instant feedback and improves perceived performance.

Use updateMessageWithReactionInfo()

Always use CometChatHelper.updateMessageWithReactionInfo() when receiving real-time reaction events to keep your message objects synchronized with the latest reaction data.

Handle Reaction Limits

Consider implementing limits on the number of reactions per message or per user to prevent spam and maintain a clean UI.

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Next Steps

Send Messages

Learn how to send text, media, and custom messages

Receive Messages

Handle real-time message events with listeners

Threaded Messages

Organize conversations with message threads

Mentions

Tag users in messages with @mentions