Create a message thread

When a user replies to a message in a channel, it creates a message thread, which refers to a collection of messages consisting of a parent message and its replies. Message threading lets users ask questions, give feedback, or add context to a specific message without disrupting the flow of conversation. It can have the following elements.

• A message can have a thread of replies.

• A message that has a thread of replies is a parent message.

• A parent message and its threaded replies are collectively called a message thread.

• Every message within a thread, whether it's parent or reply, is a threaded message.

• A message that doesn't have any replies is an unthreaded message.

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Message threading has the following limitations.

• Only 1-depth threads are supported, meaning you can only add reply messages to non-reply messages. You can't add a reply to a reply message.

• Message threading is limited to text and file messages. You can't send admin messages as replies or add replies to admin messages.

You can reply to a message in a channel through the sendUserMessage() or sendFileMessage() method. To do so, you should create a UserMessageCreateParams or a FileMessageCreateParams object and then specify the parentMessageId property of the object. Sending reply messages works the same way as sending regular messages to a channel except that replies have an additional parentMessageId property.

When replying to a message through the sendUserMessage() method, you should specify and pass a UserMessageCreateParams object to the method as a parameter. The UserMessageCreateParams class is derived from the BaseMessageCreateParams class and can access all the methods and properties of BaseMessageCreateParams.

// Create a UserMessageCreateParams object.
val params = UserMessageCreateParams().apply {
    parentMessageId = PARENT_MESSAGE_ID
    message = MESSAGE_TEXT
    replyToChannel = false
}

// Pass the params to the parameter of the sendUserMessage() method.
channel.sendUserMessage(params) { message, e ->
    if (e != null) {
        // Handle error.
    }

    // A reply to a specific message is successfully sent as a text message.
}

To see the comprehensive list of all available methods and properties, see UserMessageCreateParams.

When replying with a file message through the sendFileMessage() method, you should specify and pass a FileMessageCreateParams object to the method as a parameter. The FileMessageCreateParams class is derived from the BaseMessageCreateParams class and can access all the methods and properties of BaseMessageCreateParams.

// Create a FileMessageCreateParams object.
val params = FileMessageCreateParams().apply {
    parentMessageId = PARENT_MESSAGE_ID
    file = FILE
    fileName = FILE_NAME
    mimeType = MIME_TYPE
    fileSize = FILE_SIZE
}

// Pass the params to the parameter in the sendFileMessage() method.
channel.sendFileMessage(params) { message, e ->
    if (e != null) {
        // Handle error.
    }

    // A reply to a specific message is successfully sent as a file message.
}

To see the comprehensive list of all available methods and properties, see FileMessageCreateParams.

When replying with more than two images or videos through the sendMultipleFilesMessage() method, you should specify and pass a MultipleFilesMessageCreateParams object to the method as a parameter. Just like FileMessageCreateParams, the MultipleFilesMessageCreateParams class is derived from the BaseMessageCreateParams class and can access all the methods and properties of BaseMessageCreateParams. To learn more about how to send a multiple file message, see the Send a message page.

// Create a MultipleFilesMessageCreateParams object.
val params = MultipleFilesMessageCreateParams(uploadableFileInfoList).apply {
    parentMessageId = PARENT_MESSAGE_ID
}

// Pass the params to the parameter in the sendMultipleFilesMessage() method.
channel.sendMultipleFilesMessage(params) { message, e ->
    if (e != null) {
        // Handle error.
    }

    // A reply to a specific message is successfully sent as a multiple file message.
}

When a reply is created in a channel, the onMessageReceived() and onThreadInfoUpdated() methods of the channel event handler in client apps are called. When a reply is deleted from a thread, the onThreadInfoUpdated() event handler is invoked. In both cases, onThreadInfoUpdated() takes a ThreadInfoUpdateEvent object as an argument that has the latest information about the thread. Apply the object to the parent message object through the parentMessage.applyThreadInfoUpdateEvent() method.

override fun onThreadInfoUpdated(channel: BaseChannel, threadInfoUpdateEvent: ThreadInfoUpdateEvent) {
    // Look for a message that has threadInfoUpdateEvent.targetMessageId.
    // Apply the event to the message.
    parentMessage.applyThreadInfoUpdateEvent(threadInfoUpdateEvent)
}