为什么将地图数据解析为对象跳转

我使用这段代码将散列映射数据解析为flatter中的一个对象:

factory Channel.fromMap(Map<String, dynamic> json) => Channel(
    id: json["id"],
    author: json["author"] == null ? "" : json["author"],
    deleted: json["deleted"] == null ? false : json["deleted"],
    content: json["content"] == null ? "" : json["content"],
    dead: json["dead"] == null ? false : json["dead"],
    poll: json["poll"] == null ? null : json["poll"],
    parent: json["parent"] == null ? null : json["parent"],
    parts: json["parts"] == null
        ? []
        : List<int>.from(json["parts"].map((x) => x)),
    descendants: json["descendants"] == null ? 0 : json["descendants"],
    kids: json["kids"] == null
        ? []
        : List<int>.from(json["kids"].map((x) => x)),
    score: json["score"] == null ? 0 : json["score"],
    pubTime: json["pubTime"] == null ? 0 : json["pubTime"],
    title: json["title"] == null ? "" : json["title"],
    subName: json["subName"] == null?"":json["subName"],
    subUrl: json["subUrl"] == null?"":json["subUrl"],
    isFav: json["isFav"] == null?"":json["isFav"],
    intro: json["intro"] == null?"":json["intro"],
  );

当代码运行到此行时 isFav: json["isFav"] == null?"":json["isFav"], 对于代码,只需跳转并不返回任何内容,没有错误输出,我应该怎么做来解决这个问题?

static List<Channel> convertTheResult(Response response) {
    if (RestClient.respSuccess(response)) {
      var channelResult = response.data["result"];
      if (channelResult == null) {
        return null;
      }
      var channelListResult = channelResult["list"];
      List<Channel> channels = [];
      channelListResult.forEach((element) {
        try {
          Channel parsedChannel = Channel.fromMap(element);
          if (parsedChannel != null) {
            channels.add(parsedChannel);
          }
        } on Exception catch (e) {
          CruiseLogHandler.logError(CruiseApiError('Channel parsed failed.'), JsonEncoder().convert(response));
        }
      });
      return channels;
    }
  }

仍然没有捕捉到任何异常线索。