Flutter-参数类型"Iterable>"无法分配为“列表"类型 [英] Flutter - The argument type 'Iterable>' can't be assigned to type 'List'

问题描述

我想在每个api调用中再获得5条记录，并将它们添加到现有列表中.但是，下面的结构给出了错误.错误屏幕快照和完整的代码结构在下面提供.

I want to get 5 more records in each api call and add them to the existing list. However, the structure below gives an error. The error screenshot and the complete code structure is available below.

浏览页面初始化

 @override
  void initState() {
        exploreController.fetchArticles(offsetCount: page);
    super.initState();
    _sc.addListener(() {
      if (_sc.position.pixels == _sc.position.maxScrollExtent) {
        page = page + 5;
        exploreController.fetchArticles(offsetCount: page);
      }
    });
  }

ExploreModel

ExploreModel

List<ExploreModel> exploreModelFromJson(String str) => List<ExploreModel>.from(
    json.decode(str).map((x) => ExploreModel.fromJson(x)));

String exploreModelToJson(List<ExploreModel> data) =>
    json.encode(List<dynamic>.from(data.map((x) => x.toJson())));

我的api调用

static Future<List<ExploreModel>> fetchArticleList(int offsetCount) async {
    var url = Uri.http(Config().baseUrl, Config().baseUrlPathGetArticles,
        {'offsetCount': '$offsetCount'});
    var response = await http.get(url);
    if (response.statusCode == 200) {
      return exploreModelFromJson(utf8.decode(response.bodyBytes));
    } else {
      return null;
    }
  }

和我的控制器

class ExploreController extends GetxController {
  var isLoading = true.obs;
  var articleList = <ExploreModel>[].obs;
  var offsetCount = 0;

  @override
  void onInit() {
    fetchArticles();
    super.onInit();
  }

  void fetchArticles({int offsetCount = 0}) async {
    try {
      isLoading(true);
      var articles = await ApiService.fetchArticleList(offsetCount);

      if (articles != null) {
        for (int i = 0; i < articles.length; i++) {
          articleList.addAll(articles[i]);
        }
      }
    } finally {
      isLoading(false);
    }
  }
}

这就是我要制作的

推荐答案

更改此内容:

List<ExploreModel> exploreModelFromJson(String str) => List<ExploreModel>.from(
    json.decode(str).map((x) => ExploreModel.fromJson(x)));

对此:

List<ExploreModel> exploreModelFromJson(String str) => List<ExploreModel>.from(
    json.decode(str).map((x) => ExploreModel.fromJson(x)).toList()); //add the toList().

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