json - 未处理的异常:类型 '_InternalLinkedHashMap'不是类型转换中类型 'List'的子类型吗？

Question

这是回应

{
"overview": "A ticking-time-bomb insomniac and a slippery soap salesman channel primal male aggression into a shocking new form of therapy. Their concept catches on, with underground "fight clubs" forming in every town, until an eccentric gets in the way and ignites an out-of-control spiral toward oblivion.",
"title": "Fight Club",
}

该模型

class Movies {
  String title;
  String overview;
  

  Movies(
      {this.title , this.overview});

      factory Movies.fromJson(Map <String, dynamic> parsedJson){
        return Movies(title: parsedJson['title'] , overview: parsedJson['overview']);
      }

}

和

  Future <List<Movies>> fetchMovies () async {
    var response = await http.get(url);
    var jsonData = jsonDecode(response.body) as List ;
    List<Movies> movies = jsonData.map((e) => Movies.fromJson(e)).toList();
    
    print(movies.length);
    return movies;

  }

我收到此错误(未处理的异常:类型'_InternalLinkedHashMap '不是强制类型转换中类型'List'的子类型)

Answer 1

您尝试将jsonData转换为List，但解码器说它的类型为Map(也显示为Map类型)

Future <List<Movies>> fetchMovies () async {
  var response = await http.get(url);
  var jsonData = jsonDecode(response.body);
  if(jsonData is List) //check if it's a List
    return List<Movies>.from(jsonData.map(map) => Movies.fromJson(map));
  else if(jsonData is Map) //check if it's a Map
    return [Movies.fromJson(jsonData)]; //return a List of length 1

}