InternalLinkedHashMap<string, dynamic> ' 不是类型 'List 的子类型<dynamic> '</dynamic></string,>

Question

希望对这个错误有一些帮助。 当我尝试运行我的自动填充建议时出现错误。 我有三个打印语句来检查代码的执行情况。 我得到了“working?222”打印，但它没有进入“我到这里了吗”打印声明。 我收到以下错误。 我得到的错误是我无法修复的类型错误。 错误：类型“_InternalLinkedHashMap<String, dynamic>”不是类型“List”的子类型。 我知道这是类型不匹配，但我未能成功修复它。 这是我的代码失败的地方。 导入“飞镖：转换”； 将“包：http/http.dart”导入为 http；

class SugCompound {
  final String compound;

  const SugCompound({
    required this.compound,
  });

  static SugCompound fromJson(Map<String, dynamic> json) => SugCompound(
    compound: json['compound'],
  );
}

class SugCompoundApi {
  static Future<List<SugCompound>> getSugCompoundSuggestions(String query) async {
    //   print('working?');
    final url = Uri.parse(
        'https://website.com/rest/autocomplete/compound/$query/json?limit=6');
    final response = await http.get(url);
    print('working?222');
    if (response.statusCode == 200) {
      final List sugCompounds = json.decode(response.body);
      print('did I get here');
      return sugCompounds.map((json) => 
SugCompound.fromJson(json)).where((sugCompound)  {
    final compoundLower = sugCompound.compound.toLowerCase();
    final queryLower = query.toLowerCase();
    return compoundLower.contains(queryLower);
  }).toList();
    } else {
      throw Exception();
     // }
   }
  }
}

json looks like this:
{
    "status": {
        "code": 0
    },
    "total": 6,
    "dictionary_terms": {
        "compound": [
            "aspirin",
            "Aspirina",
            "AspirinTest2",
            "ASPIRIN (MART.)",
            "ASPIRIN COMPONENT OF AXOTAL",
            "ASPIRIN COMPONENT OF AZDONE"
        ]
    }
}

Answer 1

错误是您将 map 分配给列表的地方：

final List sugCompounds = json.decode(response.body);

现在允许，您可以像这样更改您的 class：

class SugCompound {
  final List<String> compound;

  const SugCompound({
    required this.compound,
  });

  static SugCompound fromJson(Map<String, dynamic> json) => SugCompound(
        compound: json['dictionary_terms']['compound'],
  );
}

你的未来会是这样的：

Future<List> getSugCompoundSuggestions(String query) async {
  //   print('working?');
  final url = Uri.parse(
      'https://website.com/rest/autocomplete/compound/$query/json?limit=6');
  final response = await http.get(url);

  if (response.statusCode == 200) {
    SugCompound loadedSugCompound = SugCompound.fromJson(response.body);
    List<String> compoundList = loadedSugCompound.compound;
    compoundList = compoundList
        .where((element) => element.toLowerCase().contains(query.toLowerCase()))
        .toList();
    return compoundList;
  } else {
    throw Exception();
    // }
  }

现在 future 返回一个你搜索过的列表，把它放在FutureBuilder中并显示在屏幕上