CODEWITHSUNDEEP
flutterdart
Kagimura
Kagimura

Reputation: 417

'List<dynamic>' is not a subtype of type 'List<Widget>' when trying to display a list of items

I've created a list of dates. I want to render it in a list of widgets but I'm getting an error: type 'List' is not a subtype of type 'List'. Is there a better way to render a list of dates?

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final title = 'Basic List';

    var start = DateTime.now();
    var end = DateTime(2021, 12, 31);
    var list = [];

    while (start.isBefore(end)) {
        list.add(start);
        start = start.add(Duration(days: 1));
    }


    return MaterialApp(
      title: title,
      home: Scaffold(
        appBar: AppBar(
          title: Text(title),
        ),
        body: Container(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: getDaysInWeek(),
          ),
        ),
      ),
    );
  }
}

List<Widget> getDaysInWeek() {
  var start = DateTime.now();
  var end = DateTime(2021, 12, 31);
  var list = [];
  while (start.isBefore(end)) {
    list.add(start);
    start = start.add(Duration(days: 1));
  }

  return list.toList();
}

Upvotes: 1

Views: 664

Answers (1)

creativecreatorormaybenot
creativecreatorormaybenot

Reputation: 126684

You need to map your List<DateTime to List<Widget. Intuitively this is necessary because you cannot display DateTime in Flutter, you can only display Widgets!

This could look like this:

List<Widget> get daysInWeek {
  final end = DateTime(2021, 12, 31), list = <DateTime>[];
  DateTime start = DateTime.now();

  while (start.isBefore(end)) {
    list.add(start);
    start = start.add(const Duration(days: 1));
  }

  return list.map((DateTime time) {
    return Text(time.toString());
  }).toList();
}

You will notice two things:

  1. I mapped the DateTime objects to Text objects and Text is a widget that displays Strings as text.

  2. The syntax is a little different in a few places to be more idiomatic Dart code. I am sure you will intuitively understand this syntax.

Upvotes: 1

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