import 'dart:async';
import 'question.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
String opentdb = 'https://opentdb.com/api.php?amount=15&type=boolean';
class QuestionServices {
Future<List<Question>> getData() async {
List<Question> questions;
String link = opentdb;
var res = await http
.get(Uri.encodeFull(link), headers: {"Accept": "application/json"});
print(res.body);
if (res.statusCode == 200) {
var data = json.decode(res.body);
var rest = data['results'] as List;
print(rest);
questions =
rest.map<Question>((json) => Question.fromJson(json)).toList();
}
print("List Size: ${questions.length}");
// _questions = questions;
return questions;
}
List<Question> newQuestions = getData();
}
class Question {
final String question;
final bool answer;
Question({this.question, this.answer});
factory Question.fromJson(Map<String, dynamic> json) {
return Question(
question: json['question'] as String,
answer: json['correct_answer'] as bool,
);
}
}
我正在尝试从JSON数据库创建问题列表,但是每当尝试获取返回的列表时,都会出现错误:
"A value of type 'Future<List<Question>>' can't be assigned to a variable of type 'List<Question>'."
我不确定为什么我要返回的列表给出了该错误。是否有其他方法可以将json放入列表?
最佳答案
List<Question> getData() async { // remove Future
List<Question> questions;
String link = opentdb;
...
//how to access now you will get instance of List<Question>
getData().then((List<Question> newQuestions){
})
关于json - 不能将 'Future<List<Question>>'类型的值分配给 'List<Question>'类型的变量,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/60262715/