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Manage chat rooms

Updated

Shows how to use the Agora Chat SDK to create and manage a chat room in your app.

Chat rooms enable real-time messaging among multiple users.

A chat room does not have a strict membership, and members do not retain any permanent relationship with each other. Once going offline, chat room members cannot receive any messages from the chat room and automatically leave the chat room after 2 minutes (members on the chat room allow list remain in the chat room even if they stay offline for 2 minutes or more). A chat room is widely applied in live broadcast use cases such as stream chat in Twitch.

This page shows how to use the Chat SDK to create and manage a chat room in your app.

Understand the tech

The Chat SDK provides the ChatRoom, ChatRoomManager, and ChatRoomEventHandler classes for chat room management, 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.
  • You understand the number of chat rooms supported by different pricing plans as described in Pricing Plan Details.
  • Only the app super admin has the privilege of creating a chat room. Ensure that you have added an app super admin by calling the super-admin RESTful API.

Implementation

This section introduces how to call the APIs provided by the Chat SDK to implement the features listed above.

Create a chat room

Only the app super admin can call createChatRoom to create a chat room and set the chat room attributes such as the chat room name, description, and maximum number of members. Once a chat room is created, the super admin automatically becomes the chat room owner.

You are advised to call the RESTful API to create a chat room from the server.

The following code sample shows how to create a chat room:

try {
  ChatRoom room = await ChatClient.getInstance.chatRoomManager.createChatRoom(name);
} on ChatError catch (e) {
}

Destroy a chat room

Only the chat room owner can call destroyChatRoom to disband a chat room. Once a chat room is disbanded, all chat room members receive the ChatRoomEventHandler#onChatRoomDestroyed callback and are immediately removed from the chat room.

The following code sample shows how to destroy a chat room:

try {
  await ChatClient.getInstance.chatRoomManager.destroyChatRoom(roomId);
} on ChatError catch (e) {
}

Join a chat room

Refer to the following steps to join a chat room:

  1. Call fetchPublicChatRoomsFromServer to retrieve the list of chat rooms from the server and locate the ID of the chat room that you want to join.

  2. Call joinChatRoom to pass in the chat room ID and join the specified chat room. Once a user joins a chat room, all the other chat room members receive the ChatRoomEventHandler#onMemberJoinedFromChatRoom callback.

Basic chat room joining

The following code sample shows how to join a chat room:

try {
   await ChatClient.getInstance.chatRoomManager.joinChatRoom(roomId);
} on ChatError catch (e) {
}

Advanced chat room joining with extended information

Call the ChatRoomManager#joinChatRoom(String, bool, String) method to set extended information when joining a chat room and specify whether to exit all other chat rooms. Other members in the chat room receive the ChatRoomEventHandler.onMemberJoinedFromChatRoom(String roomId, String participant, String? ext) callback with the extended information.

ChatClient.getInstance.chatRoomManager.joinChatRoom(
 "roomId",
 leaveOtherRooms: false,
 ext: 'ext',
);

// Add chat room event listener
ChatClient.getInstance.chatRoomManager.addEventHandler(
 "identifier",
 ChatRoomEventHandler(
   onMemberJoinedFromChatRoom: (roomId, participant, ext) {
     // Handle member joined event with extended information
   },
 ),
);

// Remove chat room event listener
ChatClient.getInstance.chatRoomManager.removeEventHandler("identifier");

When a user joins a chat room with extended information, other members in the chat room can access this extended information through the ext parameter in the onMemberJoinedFromChatRoom callback.

Leave a chat room

All chat room members can call leaveChatRoom to leave the specified chat room. Once a member leaves the chat room, all the other chat room members receive the ChatRoomEventHandler#onMemberExitedFromChatRoom callback.

Unlike chat group owners (who cannot leave their groups), a chat room owner can leave a chat room. After re-entering the chat room, this user remains the chat room owner.

The following code sample shows how to leave a chat room:

try {
   await ChatClient.getInstance.chatRoomManager.leaveChatRoom(roomId);
} on ChatError catch (e) {
}

By default, after a user leaves a chat room, the Chat SDK removes all chat room messages on the local device. If you do not want these messages removed, set ChatOptions#deleteMessagesAsExitChatRoom to false when initializing the SDK.

The following code sample shows how to retain the chat room messages after leaving a chat room:

ChatOptions options = ChatOptions(
      appKey: "",
      deleteMessagesAsExitChatRoom: false,
    );

Retrieve the chat room attributes

All chat room members can call fetchChatRoomInfoFromServer to retrieve the attributes of the a chat room, including the chat room ID, name, description, announcements, owner, admin list, maximum number of members, and whether all members are muted.

The following code sample shows how to retrieve the chat room attributes:

try {
  ChatRoom room = await ChatClient.getInstance.chatRoomManager.fetchChatRoomInfoFromServer(roomId);
} on ChatError catch (e) {
}

Retrieve the chat room list from the server

Users can call fetchPublicChatRoomsFromServer to retrieve the chat room list from the server.

try {
  ChatPageResult result = await ChatClient
      .getInstance.chatRoomManager
      .fetchPublicChatRoomsFromServer(
    // The page number from which to start retrieving chat rooms.
    pageNum: pageNum,
    // The maximum number of chat rooms to retrieve with pagination.
    pageSize: pageSize,
  );
} on ChatError catch (e) {
}

Listen for chat room events

To monitor the chat room events, you can listen for the callbacks in the ChatRoomEventHandler class and add app logics accordingly. If you want to stop listening for the callback, make sure that you remove the listener to prevent memory leakage.

The following code sample shows how to add and remove the chat room listener:

    /// Add a chat room event listener.
    ChatClient.getInstance.chatRoomManager.addEventHandler(
       'UNIQUE_HANDLER_ID',,
       ChatRoomEventHandler(),
        /// Occurs when a member is added to the chat room admin list.
        onAdminAddedFromChatRoom: (roomId, admin) {},

        /// Occurs when a member is removed from the chat room admin list.
        onAdminRemovedFromChatRoom: (roomId, admin) {},

        /// Occurs when the state of muting all the chat room members changes.
        onAllChatRoomMemberMuteStateChanged: (roomId, isAllMuted) {},

        /// Occurs when a member is added to the chat room allow list.
        onAllowListAddedFromChatRoom: (roomId, members) {},

        /// Occurs when a member is removed from the chat room allow list.
        onAllowListRemovedFromChatRoom: (roomId, members) {},

        /// Occurs when the chat room announcement is changed.
        onAnnouncementChangedFromChatRoom: (roomId, announcement) {},

        /// Occurs when custom chat room attributes are removed.
        onAttributesRemoved: (roomId, removedKeys, from) {},

        /// Occurs when custom chat room attributes are changed.
        onAttributesUpdated: (roomId, attributes, from) {},

        /// Occurs when the chat room instance is destroyed.
        onChatRoomDestroyed: (roomId, roomName) {},

        /// Occurs when a member leaves the chat room.
        onMemberExitedFromChatRoom: (roomId, roomName, participant) {},

        /// Occurs when a new member joins the chat room.
        onMemberJoinedFromChatRoom: (roomId, participant) {},

        /// Occurs when one or more members are added to the chat room mute list. The muted members receive this event.
        /// Since SDK v1.4.0, mutes is a Map<String, int> of each muted member's user ID to their mute expiration timestamp (a Unix timestamp in milliseconds).
        onMuteListAddedFromChatRoom: (roomId, mutes) {},

        /// Occurs when a member is removed from the chat room mute list.
        onMuteListRemovedFromChatRoom: (roomId, mutes) {},

        /// Occurs when the chat room ownership is transferred.
        onOwnerChangedFromChatRoom: (roomId, newOwner, oldOwner) {},

        ///Occurs when a chat room member is removed.
        onRemovedFromChatRoom: (roomId, roomName, participant, reason) {},

        /// Occurs when the specifications of a chat room is changed.
        onSpecificationChanged: (room) {},
      ),
    );
// ...
/// Remove a chat room event listener.
ChatClient.getInstance.chatRoomManager.removeEventHandler('UNIQUE_HANDLER_ID');

Update the chat room member count in real time

If many members join or leave a chat room in a very short time, you can update the chat room member count in real time:

  1. When a user joins a chat room, other members in the chat room receive the onMemberJoinedFromChatRoom event. When a member leaves or is removed from a chat room, other members in the chat room receive the onMemberExitedFromChatRoom event.

  2. After the event is received, you can call the getChatRoomWithId method to get local details of the chat room, including the current number of members in the chat room.

    ChatClient.getInstance.chatRoomManager.addEventHandler(
    'UNIQUE_HANDLER_ID',
    ChatRoomEventHandler(
      onMemberJoinedFromChatRoom: (roomId, participant) async {
        ChatRoom? room = await ChatClient.getInstance.chatRoomManager.getChatRoomWithId(roomId);
        debugPrint("current room member count ${room?.memberCount}");
      },
      onMemberExitedFromChatRoom: (roomId, roomName, participant) async {
        ChatRoom? room = await ChatClient.getInstance.chatRoomManager.getChatRoomWithId(roomId);
        debugPrint("current room member count ${room?.memberCount}");
      },
    ));

// ...
ChatClient.getInstance.chatRoomManager.removeEventHandler('UNIQUE_HANDLER_ID');

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