Flutter:为什么我在使用斩波器的api调用中只得到了3个结果？

Question

当调用这个接口时，我使用chopper只能得到3个结果，但是当我使用普通的http包时，我得到了更多的结果

我的斩波服务文件和我已经生成了*.chopper.dart文件

import 'package:chopper/chopper.dart';

part 'chopper_api_service.chopper.dart';

@ChopperApi(baseUrl: 'https://newsapi.org/v2')
abstract class ChopperApiService extends ChopperService {
  @Get(path: '/top-headlines')
  Future<Response> getNews({
    @Query('apiKey') String apiKey = 'secret',
    @Query('category') String category = 'health',
    @Query('country') String country = 'in'
  });

  static ChopperApiService create() {
    final client = ChopperClient(
      baseUrl: 'https://newsapi.org/v2',
      services: [
        _$ChopperApiService(),
      ],
      converter: JsonConverter(),
    );
    return _$ChopperApiService(client);
  }
}

在我试图得到结果的UI中，

import 'dart:convert';
import 'package:cached_network_image/cached_network_image.dart';
import 'package:chopper/chopper.dart';
import 'package:flutter/material.dart';
import 'package:lottie/lottie.dart';
import '../../../constants/url.dart';
import '../models/chopper_api_service.dart';


class ChopperNewsCard extends StatefulWidget {
  @override
  _ChopperNewsCardState createState() => _ChopperNewsCardState();
}

class _ChopperNewsCardState extends State<ChopperNewsCard> {
  ChopperApiService chopperApiService;
  Future<Response> apiResponse;
  @override
  void initState() {
    super.initState();
    chopperApiService = ChopperApiService.create();
    apiResponse = chopperApiService.getNews();
  }

  @override
  Widget build(BuildContext context) {
    var height = MediaQuery.of(context).size.height;
    var width = MediaQuery.of(context).size.width;

    return FutureBuilder<Response>(
      future: apiResponse,
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.done) {
          final news = jsonDecode(snapshot.data.bodyString);
          print(news);  //<-----printing it
          return Container(
            height: height * 0.37,
            width: double.infinity,
            child: ListView.builder(
              itemCount: news.length,
              physics: AlwaysScrollableScrollPhysics(),
              scrollDirection: Axis.horizontal,
              shrinkWrap: true,
              itemBuilder: (context, index) {
                return Container(
                  width: width * 0.70,
                  padding: EdgeInsets.only(right: width * 0.05),
                  child: Card(
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(15),
                    ),
                    elevation: 3,
                    child: Column(
                      children: [
                        ClipRRect(
                          borderRadius: BorderRadius.circular(15),
                          child: CachedNetworkImage(
                            imageUrl:
                                news['articles'][index]['urlToImage'] == null
                                    ? Url.noImage
                                    : news['articles'][index]['urlToImage'],//<--- this 
                            fit: BoxFit.cover,
                            width: double.infinity,
                            height: height * 0.2,
                            placeholder: (context, url) =>
                                Center(child: CircularProgressIndicator()),
                            errorWidget: (context, url, error) =>
                                Icon(Icons.error_outline_sharp),
                          ),
                        ),
                        Padding(
                          padding: EdgeInsets.only(
                              right: width * 0.03,
                              left: width * 0.03,
                              top: width * 0.03),
                          child: Text(
                            news['articles'][index]['title'],
                            maxLines: 4,
                            overflow: TextOverflow.ellipsis,
                            style: TextStyle(
                              fontWeight: FontWeight.bold,
                              fontSize: 16,
                            ),
                          ),
                        ),
                      ],
                    ),
                  ),
                );
              },
            ),
          );
        } else {
          return Center(
              child: Lottie.asset('assets/lottie/loading.json',
                  height: width * 0.5, width: width * 0.5),);
        }
      },
    );
  }
}

当打印时，它也只显示3结果，但在totalResults类别中，它显示70，

{status: ok, totalResults: 70, articles: [{source: {id: null, name: Deseret News}, author: Herb Scribner, title: Why COVID symptoms still appears if you take zinc, vitamin c - Deseret News, description: Do vitamin C and zinc help fight off COVID-19? A new sutdy says that’s not the case., url: https://www.deseret.com/u-s-world/2021/2/18/22288048/covid-19-symptoms-zinc-vitamin-c, urlToImage: https://cdn.vox-cdn.com/thumbor/6Vl9l5InMVmP9-Oqu_WVvgcThYw=/0x147:2510x1461/fit-in/1200x630/cdn.vox-cdn.com/uploads/chorus_asset/file/22294628/AP20357531088811.jpg, publishedAt: 2021-02-19T04:00:00Z, content: A new study suggests that vitamin C and zinc dont help fight off COVID-19, even when theyre taken at high doses.
Whats going on?
The study published in mid-February in JAMA Network Open found that … [+1522 chars]}, {source: {id: google-news, name: Google News}, author: null, title: Sask. health-care worker dies after positive COVID-19 test - CBC News: The National, description: null, url:<…>

现在，我是否需要在查询参数中添加某些内容以获得更多结果

Answer 1

默认情况下，newsapi每页显示20个结果。您可以通过使用pageSize和page参数来控制它。

Top headlines documentation

print(news);的输出有限，不会打印整个地图。

使用以下打印语句检查articles列表中有多少个对象：print('Articles count: ${news['articles'].length}');

您需要更改此代码才能获得商品数量：

  child: ListView.builder(
              itemCount: news['articles'].length,