我试图从Heroku的自定义API中下载json数据,大部分时间代码都能正常工作,但随机得到以下错误信息。
flutter: FormatException: Unexpected character (at character 1)
<meta name="viewport" content="width=device-width,initial-scale=1.0,maximum...
^
我有时会出现这个错误,但如果我使用相同的链接重新下载相同的文件,它就会工作,我尝试了所有的方法,但仍然无法解决。
RandomData.dart
import 'package:digest/random.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
class RandomData extends ChangeNotifier {
List<Random> articles = [];
String utf8convert(String text) {
List<int> bytes = text.toString().codeUnits;
return utf8.decode(bytes);
}
Future addArticle(String url) async {
try {
http.Response _response = await http.get("http://randomapi.com/1?q=${url.trim()}");
var decoded = utf8convert(_response.body.toString());
var decodedData = jsonDecode(decoded);
articles.add(Random(
title: decodedData['title'],
dateAdded: 'Added ${monthNames[date.month-1]} ${date.day}, ${date.year}',
link: url,
imageUrl: decodedData['image'],
));
notifyListeners();
} catch (e) {
print(e);
}
}
}
JSON响应。
{
"item_id": 5,
"title": "Example Domain",
"image": "",
"authors": [],
"date": null,
"video_links": [],
"full_text": "Example Domain\n\nThis domain is for use in illustrative examples in documents. You may use this domain in literature without prior coordination or asking for permission.\n\nMore information...",
}
请帮我解决这个问题。
我们最近在应用中遇到了类似的问题。它是由服务器返回一个 502 Bad Gateway
状态,因此响应没有包含JSON-body,而是HTML。你可以通过在解码前检查状态码来检查是否是这种情况。
if (_response.statusCode == 200) {
var decoded = // ...
} else {
print('Something went wrong; status: ${_response.statusCode}');
}
我很确定这里的情况是这样的,因为你得到的异常显示的是HTML而不是预期的JSON。<meta name="viewport" content="width=device-width,initial-scale=1.0,maximum...