Flutter类型转换错误：期望int类型却获取到String类型

问题根源 #

你的错误是因为API返回的id字段为字符串类型，但你在Course实体类中把id定义为int类型，直接用as int强制转换字符串会触发类型不匹配异常。

解决方案 #

修改Course类的fromJson工厂方法，将字符串类型的id安全转换为整数：

import 'package:equatable/equatable.dart';
import 'package:corsiapp/Domain/Course/lesson.dart';

class Course extends Equatable {
  const Course(
      {required this.id,
      required this.title,
      required this.urlImage,
      required this.description});

  final int id;
  final String title;
  final String urlImage;
  final String description;

  factory Course.fromJson(Map<String, dynamic> json) {
    return Course(
        // 用tryParse避免非数字字符串导致崩溃，可根据业务调整默认值
        id: int.tryParse(json['id'] as String) ?? 0,
        title: json['title'] as String,
        urlImage: json['urlimage'] as String,
        description: json['description'] as String);
  }

  @override
  List<Object?> get props => [id, title, urlImage, description];
}

额外调试建议 #

如果后续还有类似类型错误，可在RemoteDataSourceImpl的getCoursefromAPI方法中打印API返回的原始数据，快速定位字段类型问题：

@override
Future<List<Course>> getCoursefromAPI() async {
  final response = await client
      .get(Uri.parse('https://638c1e60eafd555746a0b852.mockapi.io/Course'));

  if (response.statusCode == 200) {
    print(response.body); // 打印原始响应，确认字段类型
    return parseCourse(response.body);
  } else {
    print('Serch Local Repository');
    throw Exception();
  }
}

内容的提问来源于stack exchange，提问作者Aitor Parrilla