`_CastError（型別 '_InternalLinkedHashMap<String, dynamic>' 不是型別轉換中的型別 'List?' 的子型別）
我正在嘗試從 jikan 我的動漫串列非官方 api 獲取 rest api。
如您所見，我正在嘗試將其轉換為串列，但我失敗了，需要幫助，它給了我頂部的錯誤。請有人讓我解決這個問題`
class HomePage extends StatefulWidget {
const HomePage({super.key});
@override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
late final future = getTopAnime();
@override
Widget build(BuildContext context) {
return Scaffold(
body: FutureBuilder<List<TopAnime>?>(
future: future,
builder: (context, snapshot) {
if (snapshot.hasData) {
return GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
),
itemCount: 10,
itemBuilder: ((context, index) {
final model = snapshot.data![index].data[index].rank;
final modell = snapshot.data![index].data[index].title;
return Card(
elevation: 20,
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(20)),
padding: EdgeInsets.all(20),
child: Column(children: [Text(modell), Text("$model")]),
),
);
}));
}
return CircularProgressIndicator();
},
),
);
}
}
Future<List<TopAnime>?> getTopAnime() async {
final response =
await http.get(Uri.parse("https://api.jikan.moe/v4/top/anime"));
if (response.statusCode == 200) {
final data = jsonDecode(response.body) as List?;
return data?.map((e) => TopAnime.fromJson(e)).toList();
} else {
throw Exception("hey");
}
}
TopAnime topAnimeFromJson(String str) => TopAnime.fromJson(json.decode(str));
String topAnimeToJson(TopAnime data) => json.encode(data.toJson());
class TopAnime {
TopAnime({
required this.data,
required this.pagination,
});
List<Datum> data;
Pagination pagination;
factory TopAnime.fromJson(Map<String, dynamic> json) => TopAnime(
data: List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
pagination: Pagination.fromJson(json["pagination"]),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
"pagination": pagination.toJson(),
};
}
class Datum {
Datum({
required this.malId,
required this.url,
required this.images,
required this.trailer,
required this.approved,
required this.titles,
required this.title,
required this.titleEnglish,
required this.titleJapanese,
required this.titleSynonyms,
required this.type,
required this.source,
required this.episodes,
required this.status,
required this.airing,
required this.aired,
required this.duration,
required this.rating,
required this.score,
required this.scoredBy,
required this.rank,
required this.popularity,
required this.members,
required this.favorites,
required this.synopsis,
required this.background,
required this.season,
required this.year,
required this.broadcast,
required this.producers,
required this.licensors,
required this.studios,
required this.genres,
required this.explicitGenres,
required this.themes,
required this.demographics,
});
int malId;
String url;
Map<String, Image> images;
Trailer trailer;
bool approved;
List<Title> titles;
String title;
String titleEnglish;
String titleJapanese;
List<String> titleSynonyms;
String type;
String source;
int episodes;
String status;
bool airing;
Aired aired;
String duration;
String rating;
int score;
int scoredBy;
int rank;
int popularity;
int members;
int favorites;
String synopsis;
String background;
String season;
int year;
Broadcast broadcast;
List<Demographic> producers;
List<Demographic> licensors;
List<Demographic> studios;
List<Demographic> genres;
List<Demographic> explicitGenres;
List<Demographic> themes;
List<Demographic> demographics;
class Image {
Image({
required this.imageUrl,
required this.smallImageUrl,
required this.largeImageUrl,
});
String imageUrl;
String smallImageUrl;
String largeImageUrl;
factory Image.fromJson(Map<String, dynamic> json) => Image(
imageUrl: json["image_url"],
smallImageUrl: json["small_image_url"],
largeImageUrl: json["large_image_url"],
);
Map<String, dynamic> toJson() => {
"image_url": imageUrl,
"small_image_url": smallImageUrl,
"large_image_url": largeImageUrl,
};
}
uj5u.com熱心網友回復：
像這樣改變你的getTopAnime()方法。回傳型別不是List. 它Map包含“資料”和“分頁”。在這里，您似乎不需要“分頁”，所以只使用這樣的“資料”。
Future<List<Datum>?> getTopAnime() async {
final response =
await http.get(Uri.parse("https://api.jikan.moe/v4/top/anime"));
if (response.statusCode == 200) {
/// Change these lines
final data = jsonDecode(response.body);
List<dynamic> res = data['data'];
final movies = res.map((dynamic d) => Datum.fromJson(d)).toList();
return movies;
} else {
throw Exception("hey");
}
}
你可以GridView像這樣使用。
itemBuilder: ((context, index) {
final model = snapshot.data![index].rank;
final modell = snapshot.data![index].title;
/// *** your code ***
}
獎勵：我已經簡化了您的代碼并實作了您想要實作的目標。隨心所欲地使用它。
代碼可以在這里找到：https ://gist.github.com/YeLwinOo-Steve/d7619f9ea53a75c6bcdb8b074b3e0e2d
而且我還建議您更深入地了解 Json Serialization and Fetching data from Api。
這里是官方資源。獲取資料：https ://dart.dev/tutorials/web/fetch-data
Json 序列化：https ://docs.flutter.dev/development/data-and-backend/json
玩得開心！
轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/529386.html
標籤：扑镖
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