Flutter Tutorial for Beginners #18 - Custom Classes

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[ahjed]

if u have Non-nullable instance field error
just add "?" like this.

String? text;
String? author;

[IRDazza]

I found I had to add 'required' to the parameters in the quote.dart file:
Quote({ required this.text, required this.author });
Otherwise I was getting an error : "can't have a value of 'null' because of its type."

[yahyafati]

If you are having a problem with creating the String fields, you have two choices:
1. Instead of "String quote" use "late String quote" or
2. Instead of "String quote" use "String? quote"

[Samir-jyxp]

"This is the qite text" - Oscar Wilde

[techchak]

Quote(author: 'Oscar Wilde', text: 'Be yourself; everyone else is already taken'),
Quote(author: 'Oscar Wilde', text: 'I have nothing to declare except my genius'),
Quote(author: 'Oscar Wilde', text: 'The truth is rarely pure and never simple')

[jashwanthgowda]

solution for new flutter version:


quote.dart

class Quote {

String? text;
String? author;

// normal constructor, as we've already seen

// Quote(String author, String text){
// this.text = text;
// this.author = author;
// }

// constructor with named parameters

// Quote({ String author, String text }){
// this.text = text;
// this.author = author;
// }

// constructor with named parameters
// & automatically assigns named arguments to class properties

Quote({ required this.text, required this.author });

}


main.dart

import
import 'quote.dart';

void main() {
runApp(MaterialApp(
home: QuoteList(),
));
}

class QuoteList extends StatefulWidget {
const QuoteList({Key? key}) : super(key: key);

@override
_QuoteListState createState() => _QuoteListState();
}

class _QuoteListState extends State<QuoteList> {
List<Quote> quotes = [
Quote(author: 'Oscar Wilde', text: 'Be yourself; everyone else is already taken'),
Quote(author: 'Oscar Wilde', text: 'I have nothing to declare except my genius'),
Quote(author: 'Oscar Wilde', text: 'The truth is rarely pure and never simple')
];

@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[300],
appBar: AppBar(
title: Text('Shani Quote App'),
centerTitle: true,
backgroundColor: Colors.redAccent,
),
body: Column(
children: quotes.map((quote) => Text('${quote.text} - ${quote.author}')).toList(),
),
);
}
}

[TheLyricalBrother]

You are awesome! This series is simply incredible. Easy to follow and good depth of content. Keep up the awesome work!

[mohamedsatti]

The way that you simplification these complex concepts is just awesome 🥰

[MojaveHigh]

What a great series! I am caught up and appreciate the breather, though I'm excited for more. :)

[MrRoxx]

A nice feature of Dart is the sugar for the construter, you can do it like this:


class Quote {
String text;
String author;


Quote(this.text, this.author);
}

[Magnetron]

Superb tutorial, Net Ninja! The best I found among the several I know! Many thanks!! Flutter rocks! 👍🏻😃

[lenzpaul]

Gonna state the obvious here. You're an amazing teacher/content creator. Thank you for the quality content

[sphereintelligence]

quote.dart needs required with the latest flutter/dart like so: Quote({required this.text, required this.author}) and an extra {} before the last }. I don't know why but it gave errors and this needed to be added. Have fun!

[algeriennesaffaires]

5:40 i stopped the video to comment and tell you man you are a live saver i never understood those named parameters just now thank you Sir

[abdullahmoiz]

Man i really can't believe how simple you make everything look

[gabrieluca]

Thanks for this amazing series! Even I'm not an expert at coding, I'm now starting to really understand Flutter.

[ahmimo]

Watching every video in this series! Great work, keep it up :)

[kosovarepublik]

Awesome job, thank you for your excellent teaching.

[amnesia]

I was wondering is there anything i can use equal like in C# List<T> and this is nice to have, custom class and lists.

[andreabollato]

Very very clear desciption; thanks very much for tutorials they're very cool