Question 78478 in Flutter Question posted in
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2 positional argument(s) expected, but 1 found. Try adding the missing – Flutter

Hello guys im new to flutter and was trying to make a news app with API. but i have an error in my homepage class, in

itemBuilder: (context, index) => listTile(articles[index])

in the (articles[index]) there is a red underland says "2 positional argument(s) expected, but 1 found. Try adding the missing". this error happen after i add "BuildContext context" to add an InkWell widget in my ListTile class

Widget listTile(Article article, BuildContext context) {
  return InkWell(
    onTap: (){
      Navigator.push(
        context, MaterialPageRoute(
          builder: (
            context) => NewsDetail(
              article: article))
      );
    },

so here is my full homepage class code

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:medreminder/NewsArticle/components/list_tile.dart';
import 'package:medreminder/NewsArticle/models/article_models.dart';
import 'package:medreminder/NewsArticle/services/api_service.dart';


class NewsHomePage extends StatelessWidget {
  //const NewsHomePage({super.key});

  ApiService client = ApiService();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Get.isDarkMode?Colors.grey[600]:Colors.white,
        leading: IconButton(
          onPressed: ()=>Get.back(),
          icon: Icon(Icons.arrow_back_ios,
          color: Get.isDarkMode?Colors.white:Colors.grey
          ),
        ),
        title:  Text("News & Article", style: TextStyle(
          color: Get.isDarkMode?Colors.white:Colors.black
        ),),
      ),
      body: FutureBuilder<List<Article>>(
        future: client.getArticle(),
        builder: (BuildContext context, AsyncSnapshot<List<Article>> snapshot) {
          if(snapshot.hasData&&snapshot.data!=null&& snapshot.data!.isNotEmpty){
            List<Article>? articles = snapshot.data;
            return ListView.builder(
              itemCount: articles!.length,
              itemBuilder: (context, index) => listTile(articles[index])
            );
          }
          return Center(child: CircularProgressIndicator(),);
        },
      ),
    );
  }
}

and here is my ListTile class

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:medreminder/NewsArticle/models/article_models.dart';
import 'package:medreminder/NewsArticle/pages/news_detail.dart';
import 'package:medreminder/Reminder/ui/theme.dart';

 Widget listTile(Article article, BuildContext context) {
  return InkWell(
    onTap: (){
      Navigator.push(
        context, MaterialPageRoute(
          builder: (
            context) => NewsDetail(
              article: article))
      );
    },
    child: Container(
      margin: EdgeInsets.all(12),
      padding: EdgeInsets.all(8),
      decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.circular(13),
          boxShadow: [BoxShadow(color: Colors.black, blurRadius: 3)]),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.start,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Container(
            height: 180,
            width: double.infinity,
            decoration: BoxDecoration(
              image: DecorationImage(image: NetworkImage(article.urlToImage!),
              fit: BoxFit.cover),
              borderRadius: BorderRadius.circular(10),
            ),
          ),
          SizedBox(height: 9),
          Container(
            padding: EdgeInsets.all(6),
            decoration: BoxDecoration(
              color: lightblueColor,
              borderRadius: BorderRadius.circular(20),
            ),
            child: Text(article.source!.name!, style: TextStyle(color: Get.isDarkMode?Colors.white:Colors.black),),
          ),
          SizedBox(
            height: 8,
          ),
          Text(
            article.title!,
            style: TextStyle(
              fontWeight: FontWeight.bold,
              fontSize: 16,
            ),
          )
        ],
      ),
    ),
  );
}

let me know if you guys needs to see more of my codes if necessary. thankyou guys

Tags:

5

Answers


  1. 0

    Try This

    itemBuilder: (context, index) => listTile(articles[index],context)

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  2. 0

    your listTile widget needs buildContext also change your code to this

    itemBuilder: (context, index) => listTile(articles[index],context)
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  3. 0

    Your listTile takes two positional argument. 1st one article and the next one is BuildContext

    Widget listTile(Article article, BuildContext context) {

    You can do

    itemBuilder: (context, index) => listTile(articles[index], context)

    But I will prefer switching the position and make the context at first. For more prefer required named argument.

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  4. 0

    You can use like below

    itemBuilder: (BuildContext  context, int index) => listTile(articles[index], context)
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  5. 0

    Okay, since you are new in flutter, I should first give you an advice and then answer your question.

    Advice

    If you starting with flutter without any previous programming experience, You should let things take time, and first start with programming basics then move to flutter.

    Now about Your Question

    Describe the problem and the solution

    In Programming, We have something called methods or functions,
    Functions are block of lines code, but separated from main program.

    and in your code above,

    Widget listTile(Article article, BuildContext context) {
 /// body
 }

    Here, ListTile is simply a function, and

    (Article article, BuildContext context)

    called function arguments, these arguments need to be passed from out side from where we call out function, in your code you call it here :

    itemBuilder: (context, index) => listTile(articles[index])

    But, what you missed that, when you create your function you create it and make it taking 2 arguments, first one is "Article", and the second is context,

    and when you call it, you forget to pass context to it, so that error shown to you says "2 positional argument(s) expected, but 1 found. "

    Final Answer

    after adding the missing parameter to function, it will be like this and the error will solved:

    itemBuilder: (context, index) => listTile(articles[index])
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