list - 指定要通过json添加到列表中的项目数

Question

如何加载要通过json添加到列表中的特定数量的项目？例如，要通过json从20个列表中加载20个项目。

 Future<List<Mentor>> _getUsers() async {
    sharedPreferences = await SharedPreferences.getInstance();
    var data = await http.get(
      NetworkUtils.host + AuthUtils.endPointMentors,
      headers: {
        'Authorization': "Bearer " + sharedPreferences.getString("token"),
        'Accept': 'application/json'
      },
    );
    var jsonData = json.decode(data.body);
    for (var u in jsonData["data"]) {
      Mentor user = Mentor(
        u["id"]!=null ? u["id"]: "",
        u["category"]!=null ? u["category"] : "",
        u["email"]!=null ? u["email"]: "",
        u["email_verified_at"] !=null ? u["email_verified_at"]: "",
        u["first_name"] !=null ? u["first_name"]: "",
        u["last_name"] != null ?u["last_name"]: "",
        u["other_name"] !=null ? u["other_name"]: "",
        u["country"] !=null ? u["country"]: "",
        u["industry"] !=null ? u["industry"]: "",
        u["gender"] !=null ? u["gender"]: "",
        u["bio_interest"] !=null ? u["bio_interest"]: "",
        u["phone"] !=null ?u["phone"]: "",
        u["state_of_origin"] !=null ? u["state_of_origin"]: "",
        u["fav_quote"] != null ? u["fav_quote"]: "",
        u["profile_image"] != null ? u["profile_image"] : "",
        u["terms"] !=null ? u["terms"]: "",
        u["check_status"] !=null ? u["check_status"]: "",
        u["current_job"] != null ? u["current_job"]: "",
        u["created_at"] !=null ? u["created_at"]: "",
        u["updated_at"]!=null ? u["updated_at"]: "",
        u["social_id"] !=null ? u["social_id"]: "",
        getFromList(u["employment"], 'company'),
        getFromList(u['employment'], 'position'),
        getFromList(u['education'], 'institution'),
        getFromList(u['education'], 'degree'),);

      users.add(user);
//this adds all the users to the list. I want say 10 items to be loaded into the list.
    }
    return filteredData;
  }

因此，这会将所有数据加载到我的列表中。如何从列表中加载而不是全部加载10个项目？

Answer 1

您可以在take上使用 Iterable 方法返回新的Iterable，该Iterable仅返回前n个条目。因此，您应该能够像这样获得前10个条目:

...
    var jsonData = json.decode(data.body);
    for (var u in jsonData["data"].take(10)) {
      Mentor user = Mentor(
...