Question

我正在尝试读取JSON响应并使用Flutter的FutureBuilder构建UI，但无法在客户端上获得整个JSON响应。当我尝试在两个不同的打印语句中打印响应时，它们之间的内容差别很小。请注意，以下控制台打印输出对于我的帖子API响应和我的帖子Json响应字符串。

有人可以解释这种行为以及如何在客户端接收到完整的JSON数组之前实施适当的侦听吗？

预期的API响应-

[{"_id":"5bd11c9b8a9fc0a744d1bebc","postId":1,"postUserId":1,"postDescription":"First Post with 2 Photos","postLongDescription":"First Post with 2 Photos","postDateTime":"2018-07-27T10:50:42.389Z","postLocationId":1,"postHasMedia":true,"postActive":true,"postLikesCount":3,"postCommentsCount":1},{"_id":"5bd11c9b8a9fc0a744d1bebd","postId":2,"postUserId":2,"postDescription":"Second Post with 1 Video","postLongDescription":"Second Post with 1 Video","postDateTime":"2018-07-27T11:02:00.389Z","postLocationId":2,"postHasMedia":true,"postActive":true,"postLikesCount":12,"postCommentsCount":2},{"_id":"5bd11c9b8a9fc0a744d1bebe","postId":3,"postUserId":2,"postDescription":"Third Post with No Video","postLongDescription":"Third Post with No Video","postDateTime":"2018-07-27T11:12:34.389Z","postLocationId":3,"postHasMedia":false,"postActive":true,"postLikesCount":9,"postCommentsCount":0},{"_id":"5bd11c9b8a9fc0a744d1bebf","postId":4,"postUserId":3,"postDescription":"Fourth Post with 1 Photo but Disabled","postLongDescription":"Fourth Post with 1 Photo but Disabled","postDateTime":"2018-07-27T11:12:34.389Z","postLocationId":2,"postHasMedia":true,"postActive":false,"postLikesCount":4,"postCommentsCount":0}]

颤振区码-

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:MyApp/models/post_model.dart';    
import 'package:http/http.dart' as http;    

enum storyTypes {
    timeline,
    myposts
}

class PostsBloc {

Future<PostModel> getPosts(storyTypes storyType) async {
    if (storyType == storyTypes.myposts) {
        final String url = "http://127.0.0.1:8081/posts/all";
        return await http.get(url).then((getMyPostsApiResponse) {
            if (getMyPostsApiResponse.statusCode != 200) {
            throw Exception("Error with http over network");
            }
            else {
            if (getMyPostsApiResponse.statusCode == 200) {
                print('My Posts API Response - ' + getMyPostsApiResponse.body);                    
                print('My Posts Json Response String - ' + json.decode(getMyPostsApiResponse.body).toString());
                return PostModel.fromJson(json.decode(getMyPostsApiResponse.body));
            }
            else {
                throw Exception('Failed to load post');
            }
            }
        });
    }
}

Flutter控制台输出-

I/flutter (32316): My Posts API Response - [{"_id":"5bd11c9b8a9fc0a744d1bebc","postId":1,"postUserId":1,"postDescription":"First Post with 2 Photos","postLongDescription":"First Post with 2 Photos","postDateTime":"2018-07-27T10:50:42.389Z","postLocationId":1,"postHasMedia":true,"postActive":true,"postLikesCount":3,"postCommentsCount":1},{"_id":"5bd11c9b8a9fc0a744d1bebd","postId":2,"postUserId":2,"postDescription":"Second Post with 1 Video","postLongDescription":"Second Post with 1 Video","postDateTime":"2018-07-27T11:02:00.389Z","postLocationId":2,"postHasMedia":true,"postActive":true,"postLikesCount":12,"postCommentsCount":2},{"_id":"5bd11c9b8a9fc0a744d1bebe","postId":3,"postUserId":2,"postDescription":"Third Post with No Video","postLongDescription":"Third Post with No Video","postDateTime":"2018-07-27T11:12:34.389Z","postLocationId":3,"postHasMedia":false,"postActive":true,"postLikesCount":9,"postCommentsCount":0},{"_id":"5bd11c9b8a9fc0a744d1bebf","postId":4,"postUserId":3,"postDescription":"Fourth Post with 1 Photo but Dis    
I/flutter (32316): My Posts Json Response String - [{_id: 5bd11c9b8a9fc0a744d1bebc, postId: 1, postUserId: 1, postDescription: First Post with 2 Photos, postLongDescription: First Post with 2 Photos, postDateTime: 2018-07-27T10:50:42.389Z, postLocationId: 1, postHasMedia: true, postActive: true, postLikesCount: 3, postCommentsCount: 1}, {_id: 5bd11c9b8a9fc0a744d1bebd, postId: 2, postUserId: 2, postDescription: Second Post with 1 Video, postLongDescription: Second Post with 1 Video, postDateTime: 2018-07-27T11:02:00.389Z, postLocationId: 2, postHasMedia: true, postActive: true, postLikesCount: 12, postCommentsCount: 2}, {_id: 5bd11c9b8a9fc0a744d1bebe, postId: 3, postUserId: 2, postDescription: Third Post with No Video, postLongDescription: Third Post with No Video, postDateTime: 2018-07-27T11:12:34.389Z, postLocationId: 3, postHasMedia: false, postActive: true, postLikesCount: 9, postCommentsCount: 0}, {_id: 5bd11c9b8a9fc0a744d1bebf, postId: 4, postUserId: 3, postDescription: Fourth Post with 1 Photo but Disabled, postLongDescr

Answer 1

好像您在Android上尝试打印长字符串。引用documentation about debugging：

Dart print（）函数输出到系统控制台，您可以   使用颤动日志（基本上是adb的包装器）进行查看   logcat）。

如果一次输出太多，则Android有时会丢弃一些   日志行。为避免这种情况，您可以使用Flutter的   基础图书馆。这是围绕打印的包装，可限制打印   输出到避免被Android内核丢弃的水平。

所以您可以尝试使用debugPrint。

导入Flutter软件包以使用debugPrint-import 'package:flutter/foundation.dart';

Answer 2

那只是控制台在输入这么多字符后被截断。

请注意，您要打印两种不同的东西：

getMyPostsApiResponse.body是从服务器接收的json。

json.decode(getMyPostsApiResponse.body).toString()是解码后的List的toString（不包括引号，这就是字符串长度不同的原因）

Dart Http客户端返回截断的响应，当我打印到控制台时截断略有不同

2 个答案: