Question

我正在扑朔迷离地学习TDD（测试驱动开发）。在这里，我试图解析我的JSON数据，但是每次运行测试时，我都会得到一个错误提示。

错误：类型'String'不是'索引'的类型'int'的子类型

这些是我的代码

weather_app_model_test.dart

  group('fromJson', () {
    test('should return a valid model', () async {
      final Map<String, dynamic> jsonMap =
          json.decode(fixture('weather_app.json'));
      final result = WeatherAppModel.fromJson(jsonMap);
      expect(result, tWeatherAppModel);
    });
  });

weather_app_model.dart

factory WeatherAppModel.fromJson(Map<String, dynamic> json) {
    return WeatherAppModel(
      weatherMain: json['weather']['main'],
      weatherDescription: json['weather']['description'],
      temp: json['main']['temp'],
      minTemp: json['main']['temp_min'],
      maxTemp: json['main']['temp_main'],
      country: json['sys']['country'],
    );
  }

fixtures / weather_app.json

{
  "coord": {
    "lon": 78,
    "lat": 20
  },
  "weather": [
    {
      "id": 500,
      "main": "Rain",
      "description": "light rain",
      "icon": "10d"
    }
  ],
  "base": "model",
  "main": {
    "temp": 301.51,
    "pressure": 1014,
    "humidity": 67,
    "temp_min": 301.51,
    "temp_max": 301.51,
    "sea_level": 1014,
    "grnd_level": 979
  },
  "wind": {
    "speed": 3.19,
    "deg": 77
  },
  "rain": {
    "3h": 1.81
  },
  "clouds": {
    "all": 45
  },
  "dt": 1572672029,
  "sys": {
    "country": "IN",
    "sunrise": 1572655775,
    "sunset": 1572696807
  },
  "timezone": 19800,
  "id": 1272596,
  "name": "Digras",
  "cod": 200
}

任何帮助都会很棒。

Answer 1

factory WeatherAppModel.fromJson(Map<String, dynamic> json) {
    return WeatherAppModel(
      weatherMain: json['weather'][0]['main'],
      weatherDescription: json['weather'][0]['description'],
      temp: json['main']['temp'],
      minTemp: json['main']['temp_min'],
      maxTemp: json['main']['temp_main'],
      country: json['sys']['country'],
    );
  }

这将解决您的问题。 json['weather']不像map那样返回，它是一个数组。它以[0]为第一个值。

错误：在flutter中使用fromjson时，类型'String'不是'index'类型'int'的子类型

1 个答案: