Flutter List 未在异步方法之外更新

Question

我在 2 个字符串列表中添加数据，但在它们显示 0 长度的方法之外。但在 fetchList 方法中，它们显示 1643 长度。

  fetchList() async {
setState(() {
  isLoading=true;
});

var response = await http.get(Uri.parse("https://type.fit/api/quotes"));
var data = json.decode(response.body);

if (response.statusCode == 200) {
  for (var i in data) {
    var response2 = await http.get(Uri.parse(
        "https://api.unsplash.com/search/photos?client_id=$unsplashAPIKey&query=${i['author']}"));
    quoteList.add(
      QuoteListClass(
        quote: i['text'] != null ? i['text'] : 'Anonymous',
        author: i['author'] != null ? i['author'] : '',
        image: response2.statusCode == 200
            ? json.decode(response2.body)['results'][0]['urls']['raw']
            : '',
      ),
    );
    print(json.decode(response2.body)['results'][0]['urls']['raw']);
  }
} else {
  throw Exception('Failed to load quotes');
}

setState(() {
  isLoading = false;
});
}
 @override
   void initState() {
      super.initState();
      Future.delayed(Duration.zero,()async{
        this.fetchList();
      });
   }

现在有一个新错误。

E/flutter (9830): [错误:flutter/lib/ui/ui_dart_state.cc(186)] 未处理的异常：RangeError（索引）：无效值：有效值 范围为空：0 E/flutter（9830）：#0 List.[] (dart:core-patch/growable_array.dart:254:60)

Answer 1

如下编辑initState函数

@override
  void initState() {
    super.initState();
    Future.delayed(Duration.zero,()async{
       this.fetchList();
    });
}