Thread messages

Updated

Show how to use the Agora Chat SDK to send, receive, recall, and retrieve thread messages in your app.

Threads enable users to create a separate conversation from a specific message within a chat group to keep the main chat uncluttered.

This page shows how to use the Chat SDK to send, receive, recall, and retrieve thread messages in your app.

Understand the tech

The Chat SDK provides the ChatThreadManager, ChatMessage, and ChatThread classes for thread messages, which allows you to implement the following features:

Prerequisites

Before proceeding, ensure that you meet the following requirements:

  • You have initialized the Chat SDK. For details, see SDK quickstart.
  • You understand the call frequency limit of the Chat APIs supported by different pricing plans as described in Limitations.

The thread feature is supported by all types of Pricing Plans and is enabled by default once you have enabled Chat in Agora Console.

Implementation

This section describes how to call the APIs provided by the Chat SDK to implement thread features.

Send a thread message

Sending a thread message is similar to sending a message in a chat group. The difference lies in the isChatThreadMessage field, as shown in the following code sample:

// Sets `targetId` to thread ID.
// Sets `content` to the message content.
ChatMessage msg = ChatMessage.createTxtSendMessage(
  targetId: threadId,
  content: content,
  chatType: ChatType.GroupChat,
);
// Sets `isChatThreadMessage` to `true` to mark this message as a thread message.
msg.isChatThreadMessage = true;
//  Sends the message.
ChatClient.getInstance.chatManager.sendMessage(msg);

For more information about sending a message, see Send Messages.

Receive a thread message

Once a thread has a new message, all chat group members receive the ChatThreadEventHandler#onChatThreadUpdated callback. Thread members can also listen for the ChatEventHandler#onMessagesReceived callback to receive thread messages, as shown in the following code sample:

  // Adds the chat event handler.
  ChatClient.getInstance.chatManager.addEventHandler(
    "UNIQUE_HANDLER_ID",
    ChatEventHandler(
      onMessagesReceived: (messages) {},
    ),
  );
  // Adds the thread event handler.
  ChatClient.getInstance.chatThreadManager.addEventHandler(
    "UNIQUE_HANDLER_ID",
    ChatThreadEventHandler(
      onChatThreadUpdate: (event) {},
    ),
  );
  ...
  // Removes the chat event handler.
  ChatClient.getInstance.chatManager.removeEventHandler("UNIQUE_HANDLER_ID");
  // Removes the chat thread event handler.
  ChatClient.getInstance.chatThreadManager.removeEventHandler("UNIQUE_HANDLER_ID");

For more information about receiving a message, see Receive Messages.

Recall a thread message

For details about how to recall a message, refer to Recall Messages.

Once a message is recalled in a thread, all chat group members receive the ChatThreadEventHandler#onChatThreadUpdated callback. Thread members can also listen for the ChatEventHandler#onMessagesRecalled callback, as shown in the following code sample:

  // Adds the chat event handler.
  ChatClient.getInstance.chatManager.addEventHandler(
    "UNIQUE_HANDLER_ID",
    ChatEventHandler(
      onMessagesRecalled: (messages) {},
    ),
  );
  // Adds the thread event handler.
  ChatClient.getInstance.chatThreadManager.addEventHandler(
    "UNIQUE_HANDLER_ID",
    ChatThreadEventHandler(
      onChatThreadUpdate: (event) {},
    ),
  );
  ...
  // Removes the chat event handler.
  ChatClient.getInstance.chatManager.removeEventHandler("UNIQUE_HANDLER_ID");
  // Removes the chat thread event handler.
  ChatClient.getInstance.chatThreadManager.removeEventHandler("UNIQUE_HANDLER_ID");

Retrieve thread messages

You can retrieve thread messages locally or from the server, depending on your production environment. You can check ChatConversation#isChatThread() to determine whether the current conversation is a thread conversation.

Retrieve messages of a thread from the server

You can call fetchHistoryMessages to retrieve messages of a thread from the server. The only difference between retrieving messages of a thread from the server and retrieving group messages is that a thread ID needs to be passed in for the former and a group ID is required for the latter.

try {
  // The thread ID.
  String threadId = "threadId";
  // The conversation type is set to `GroupChat` as a thread belongs to a group conversation.
  ChatConversationType convType = ChatConversationType.GroupChat;
  // The number of thread messages that you expect to get on each page.
  int pageSize = 10;
  // The starting message ID for retrieving.
  String startMsgId = "";
  ChatCursorResult cursor =
      await ChatClient.getInstance.chatManager.fetchHistoryMessages(
    conversationId: convId,
    type: convType,
    pageSize: pageSize,
    startMsgId: startMsgId,
  );
} on ChatError catch (e) {
}

Retrieve messages of a thread locally

By calling loadAllConversations, you can only retrieve local one-to-one chat conversations and group conversations. To retrieve messages of a thread locally, refer to the following code sample:

try {
  // The thread ID.
  String threadId = "threadId";
  // The conversation type is set to `GroupChat` as a thread belongs a group conversation.
  ChatConversationType convType = ChatConversationType.GroupChat;
  ChatConversation? conversation = await ChatClient.getInstance.chatManager
        .getThreadConversation(threadId);
  // The starting message for retrieving.
  String startMsgId = "startMsgId";
  // The number of messages that you expect to retrieve on each page.
  int pageSize = 10;
  List? list = await conversation?.loadMessages(
      startMsgId: startMsgId, loadCount: pageSize);
} on ChatError catch (e) {}