"The body might complete normally, causing 'null' to be returned, but the return type, 'FutureOr<List<Article>>', is a potentially non-nullable type."

Question

I was trying to make a News App with newsapi.org, but got this error:

The body might complete normally, causing 'null' to be returned, 
but the return type, 'FutureOr<List<Article>>', is a potentially non-nullable type.
Try adding either a return or a throw statement at the end.

Error from:

getArticle()

I've read a lot of ppl with the same problem and most of them told me to add return or a throw, which I already did but the error still appears.

So here's my code:

import 'dart:convert';
import 'package:http/http.dart';
import 'package:medreminder/NewsArticle/models/article_models.dart';

class ApiService {
  final endPointUrl = 
      "https://newsapi.org/v2/top-headlines?country=us&apiKey=cacee27fff544eb39d5fb29b28ca3788"; 

  Future<List<Article>> getArticle() async {
    Response res = await get(Uri.parse(endPointUrl));

    if(res.statusCode == 200) {
      Map<String, dynamic> json = jsonDecode(res.body);
      List<dynamic> body = json['articles'];
      List<Article> articles = 
          body.map((dynamic item) => Article.fromJson(item)).toList();
    } else {
      throw("Cant get the News");
    }
  }
}

Let me know if you guys need to see my other code if necessary. Thank you guys

Answer 1

As the error states:

Try adding either a return or a throw statement at the end.

You need to return something. In your case it's a List<Article>.

I've read a lot of ppl with the same problem, most of them told to add return or a throw, which I already did but the error still appearing.

This is probably because you are adding the return statement within your if/else statement, so if your condition isn't met, then you still might not return anything.

To avoid the error, your code should look like this (null safe):

 Future<List<Article>?> getArticle() async{
    Response res = await get(Uri.parse(endPointUrl));

    if(res.statusCode==200){
      Map<String, dynamic> json = jsonDecode(res.body);

      List<dynamic> body = json['articles'];

      List<Article> articles = body.map((dynamic item) => Article.fromJson(item)).toList();
      return articles;
    }else{

      return null;
    }

  }

Now, this function is nullable - which means that if the response is 200, it will return the articles. Otherwise, it will return null