my screen doesn't update when i update my list flutter

Question

Hello i'm new in flutter development i try to make a simple quiz app and keep the score in a list.

I have a list of icons i put it in a Row widget so when i press the true or false button my list add a widget(icon) to my row and display it .

But my screen doesn't update when i press the button until i hot reload or hot restart the app

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() => runApp(Quizzler());

class Quizzler extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.grey.shade900,
        body: SafeArea(
          child: Padding(
            padding: EdgeInsets.symmetric(horizontal: 10.0),
            child: QuizPage(),
          ),
        ),
      ),
    );
  }
}

class QuizPage extends StatefulWidget {
  @override
  _QuizPageState createState() => _QuizPageState();
}

class _QuizPageState extends State<QuizPage> {
  List<Widget> scorekepper = [];

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: <Widget>[
        Expanded(
          flex: 5,
          child: Padding(
            padding: EdgeInsets.all(10.0),
            child: Center(
              child: Text(
                'This is where the question text will go.',
                textAlign: TextAlign.center,
                style: TextStyle(
                  fontSize: 25.0,
                  color: Colors.white,
                ),
              ),
            ),
          ),
        ),
        Expanded(
          child: Padding(
            padding: EdgeInsets.all(15.0),
            child: FlatButton(
              textColor: Colors.white,
              color: Colors.green,
              child: Text(
                'True',
                style: TextStyle(
                  color: Colors.white,
                  fontSize: 20.0,
                ),
              ),
              onPressed: () {
                scorekepper.add(Icon(
                  Icons.check,
                  color: Colors.green,
                ));
              },
            ),
          ),
        ),
        Expanded(
          child: Padding(
            padding: EdgeInsets.all(15.0),
            child: FlatButton(
              color: Colors.red,
              child: Text(
                'False',
                style: TextStyle(
                  fontSize: 20.0,
                  color: Colors.white,
                ),
              ),
              onPressed: () {
                scorekepper.add(
                  Icon(
                    Icons.close,
                    color: Colors.red,
                  ),
                );
              },
            ),
          ),
        ),
        Row(
          children: scorekepper,
        ),
      ],
    );
  }
}

akram abdullah · Accepted Answer · 2021-08-20 16:55:15Z

2

setState(() {
              scorekepper.add(
                Icon(
                  Icons.close,
                  color: Colors.red,
                ),
              );
            });

answered Aug 20, 2021 at 16:55

akram abdullah

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Comments

LITON · Accepted Answer · 2021-08-20 16:56:03Z

1

You need to put setState(() {}); after your function. This will run the build function so that it can refresh your screen and display the icon. See more here.

 onPressed: () {
                scorekepper.add(Icon(
                  Icons.check,
                  color: Colors.green,
                ));
                setState(() {});
              },

answered Aug 20, 2021 at 16:56

LITON

111 bronze badge

Comments

Mohamad Alzabibi · Accepted Answer · 2021-08-20 17:49:02Z

0

What is happening that you are adding item to list but not refreshing the UI,so in order to refresh the UI you have many options, the easiest way is to do setState(){} on add, Although i recommend you to search about state management like: Bloc, Provider ...etc, which will optimize the performance the app when rebuilding.

answered Aug 20, 2021 at 17:49

Mohamad Alzabibi

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