loadMessage method
- String messageId
~english Gets the message with a specific message ID.
If the message is already loaded into the memory cache, the message will be directly returned; otherwise, the message will be loaded from the local database and loaded in the memory.
Param messageId The message ID.
Return The message instance.
Throws A description of the exception. See ChatError. ~end
~chinese 获取指定 ID 的消息。
优先从内存中加载,如果内存中没有则从数据库中加载,并将其插入到内存中。
Param messageId 消息 ID。
Return 消息实例。
Throws 如果有异常会在这里抛出,包含错误码和错误描述,详见 ChatError。 ~end
Implementation
Future<ChatMessage?> loadMessage(String messageId) async {
  Map req = this._toJson();
  req['msg_id'] = messageId;
  Map result = await _emConversationChannel.invokeMethod(
      ChatMethodKeys.loadMsgWithId, req);
  try {
    ChatError.hasErrorFromResult(result);
    if (result[ChatMethodKeys.loadMsgWithId] != null) {
      return ChatMessage.fromJson(result[ChatMethodKeys.loadMsgWithId]);
    } else {
      return null;
    }
  } on ChatError catch (e) {
    throw e;
  }
}