在骇客新闻中的颤振小部件测试中，类型“int”不是“String”类型的子类型

Posted 2023-02-23

【中文标题】在骇客新闻中的颤振小部件测试中，类型“int”不是“String”类型的子类型

【英文标题】：type 'int' is not a subtype of type 'String' in flutter widget test in hacker news

【发布时间】：2020-12-28 16:17:14

【问题描述】：

正如你已经知道的那样，他们制作了一个 Flutter 黑客新闻应用程序，这是一个无聊的 Flutter 节目。如果我正在实施相同的操作来了解应用程序的测试。我遇到了这个问题。 “int”类型不是“String”类型的子类型。 我只实施了三个测试。 json_test.dart

import 'package:flutter_test/flutter_test.dart';
import '../lib/jsonparsing.dart';

void main() async 
  test("parses topstories.json", () 
    const jsonString =
        "[24429012,24426500,24426882,24422593,24426407,24427978,24420177,24428206,24426617,24427417,24428755,24422897,24410641,24424910,24422432,24423463,24424462,24428693,24421907,24427617,24426917,24423637,24426641,24425843,24411110,24404595,24428907,24424073,24409543,24422491,24425424,24403827,24422472,24428810,24423544,24423023,24421331,24428943,24422808,24420120,24427311,24427596,24402763,24425870,24426207,24422441,24419441,24423610,24424698,24427706,24428633,24424992,24426131,24426441,24422416,24413394,24421018,24422547,24419042,24423208,24421247,24427930,24428402,24420874,24417015,24408509,24412970,24419081,24407432,24401999,24422092,24406193,24424040,24417319,24416908,24413705,24416807,24402839,24422333,24427247,24419803,24412881,24422720,24415760,24428372,24414497,24402429,24425776,24419660,24426023,24419947,24425121,24428572,24424335,24403076,24428554,24417482,24402202,24401927,24416005,24419844,24425625,24410596,24404189,24414949,24417079,24423614,24423600,24414252,24425268,24418854,24425111,24411344,24407706,24424989,24422729,24423540,24410530,24412179,24410627,24415872,24421934,24407204,24423602,24423534,24419875,24401439,24427083,24406714,24424208,24418838,24426107,24401664,24411357,24424829,24420304,24404814,24419574,24410113,24416112,24427169,24427165,24422599,24422365,24422358,24404002,24412810,24411991,24421073,24427696,24422148,24406611,24401085,24411076,24421034,24421767,24424621,24427045,24425909,24404808,24409093,24412687,24425797,24423484,24407241,24424872,24414877,24413629,24408077,24409334,24404628,24407323,24411540,24425146,24426014,24420692,24403070,24408185,24421020,24408511,24407674,24405632,24426573,24401805,24408324,24406366,24403464,24402419,24411786,24405758,24407005,24426178,24424804,24426132,24426108,24426631,24407849,24407272,24402937,24413746,24403211,24401748,24410681,24405981,24401546,24404742,24411315,24405884,24407232,24421061,24405941,24403351,24423612,24420975,24405776,24425056,24418802,24407601,24411162,24426728,24407321,24410472,24407844,24422487,24402107,24401462,24423332,24401565,24418930,24415294,24415252,24403236,24402467,24423399,24416458,24401246,24403392,24401206,24404555,24414671,24406921,24406829,24408717,24422463,24412936,24404681,24408201,24412549,24418171,24405214,24425068,24411693,24411554,24403566,24419664,24416977,24407122,24409695,24404113,24417890,24425794,24418248,24420592,24408813,24403461,24420359,24415180,24407444,24410575,24403095,24401112,24402543,24409919,24411253,24404671,24416894,24402125,24404357,24406683,24413393,24413737,24406046,24409972,24405876,24413045,24405946,24413554,24405517,24418345,24418856,24408773,24405960,24401221,24410652,24418598,24409327,24418523,24404968,24410991,24411834,24401124,24414153,24413823,24406276,24424567,24423129,24425498,24415528,24422788,24403306,24403255,24414448,24405833,24414301,24401287,24411683,24406577,24403862,24406418,24416379,24421236,24412657,24404704,24420996,24420777,24406341,24405512,24402885,24405253,24404200,24414222,24421155,24408228,24419521,24407430,24411758,24405455,24421761,24405294,24401352,24411207,24403633,24411030,24406818,24402075,24405279,24418561,24401245,24405942,24420567,24405634,24405583,24413574,24404921,24401450,24405651,24410121,24401519,24403647,24406270,24413835,24412451,24405814,24405736,24402536,24405600,24422368,24405438,24425763,24404549,24404182,24410125,24413607,24408109,24406632,24410299,24401107,24405100,24402849,24406446,24404657,24426389,24425252,24409970,24402841,24402617,24401415,24405318,24402404,24403967,24415907,24407797,24412792,24428579,24424763]";
    expect(
      parseTopStories(jsonString).first,
      24429012,
    );
  );
  test("parses Articles.json", () 
    const jsonString =
        """"by":"dhouston","descendants":71,"id":8863,"kids":[9224,8917,8952,8958,8884,8887,8869,8940,8908,9005,8873,9671,9067,9055,8865,8881,8872,8955,10403,8903,8928,9125,8998,8901,8902,8907,8894,8870,8878,8980,8934,8943,8876],"score":104,"time":1175714200,"title":"My YC app: Dropbox - Throw away your USB drive","type":"story","url":"http://www.getdropbox.com/u/2/screencast.html"""";
    expect(
      parseArticle(jsonString).by,
      "dhouston",
    );
  );

json_parsing.dart

import './models/article.dart';
import 'dart:convert' as json;

List<int> parseTopStories(String jsonStr) 
  final parsed = json.jsonDecode(jsonStr);
  final listofIds = List<int>.from(parsed);
  return listofIds;


Article parseArticle(String jsonStr) 
  final parsed = json.jsonDecode(jsonStr);
  Article article = Article.fromJson(parsed);
  return article;

article.dart

class Article 
  final int id;
  final String title;
  final String url;
  final String type;
  final String by;
  final int time;
  final int score;
  final int descendants;
  final List<int> kids;

  const Article(
    this.id,
    this.title,
    this.url,
    this.type,
    this.by,
    this.time,
    this.score,
    this.descendants,
    this.kids,
  );
  factory Article.fromJson(Map<String, dynamic> json) 
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['score'],
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  

widget_test.dart

// This is a basic Flutter widget test.
//
// To perform an interaction with a widget in your test, use the WidgetTester
// utility that Flutter provides. For example, you can send tap and scroll
// gestures. You can also use WidgetTester to find child widgets in the widget
// tree, read text, and verify that the values of widget properties are correct.

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:hacker_app/main.dart';

void main() 
  testWidgets('Hacker News', (WidgetTester tester) async 
    // Build our app and trigger a frame.
    await tester.pumpWidget(MyApp());
    expect(find.byIcon(Icons.launch), findsNothing);

    await tester.tap(find.byType(ExpansionTile).first);

    await tester.pumpAndSettle();
    expect(find.byIcon(Icons.launch), findsOneWidget);
  );

00:06 +1 -1: C:\Users\Shary\Desktop\Development\practice\hackerapp\test\json_test.dart: parses item.json [E]
  type 'int' is not a subtype of type 'String'
  ..\lib\models\article.dart 30:18  new Article.fromJson
  ..\lib\jsonparsing.dart 12:29     parseArticle
  json_test.dart 17:7               main.<fn>

【问题讨论】：

您遇到错误的地方，确切的行会有所帮助

请发布完整的错误消息，因为它将包含有关问题发生位置的有用信息。

00:06 +1 -1: C:\Users\Shary\Desktop\Development\practice\hackerapp\test\json_test.dart: 解析 item.json [E] type 'int' 不是'String' 类型的子类型 ..\lib\models\article.dart 30:18 new Article.fromJson ..\lib\jsonparsing.dart 12:29 parseArticle json_test.dart 17:7 main.

article.dart 30:18 ... 意思是在您的文件 article.dart，第 30 行，字符 18... 发生错误

是的，但我正在传递字符串

【参考方案1】：

编辑：虽然我的回答回答了您提出的问题，正如另一个回答中指出的那样，您可能不想使用title: json['score']，而是使用title: json['title']。

您正在尝试将 int 用作字符串。查看错误代码，它会告诉您是哪一行导致了错误。

根据您的错误代码，该错误发生在 article.dart 的第 30 行。

这个：

title: json['score']

title 可能期待 String 而json['score'] 可能返回一个 int。

只需像这样添加.toString()：

title: json['score'].toString()  //now it is a String

【参考方案2】：

对 score 属性的 JSON 解析错误，您必须使用全局提到的 String 的相应字段

替换

 factory Article.fromJson(Map<String, dynamic> json) 
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['score'], // This should be title as score you alredy added at the bottom
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  

有

 factory Article.fromJson(Map<String, dynamic> json) 
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['title'],
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  

【讨论】：

@Shahryar Rafique：完全不同意你我的回答是正确的，如果我没有错，因为你使用了错误的属性。你能解释为什么它不准确吗？