text stringlengths 1 474 |
|---|
a column of text, a star icon, and a number. |
Its first child, the column, contains two lines of text. |
That first column might need more space.Row 2, the Button section, has three children: each child contains |
a column which then contains an icon and text.After diagramming the layout, consider how you would code it.Would you write all the code in one class? |
Or, would you create one class for each part of the layout?To follow Flutter best practices, create one class, or Widget, |
to contain each part of your layout. |
When Flutter needs to re-render part of a UI, |
it updates the smallest part that changes. |
This is why Flutter makes “everything a widget”. |
If only the text changes in a Text widget, Flutter redraws only that text. |
Flutter changes the least amount of the UI possible in response to user input.For this tutorial, write each element you have identified as its own widget.<topic_end> |
<topic_start> |
Create the app base code |
In this section, shell out the basic Flutter app code to start your app.Set up your Flutter environment.Create a new Flutter app.Replace the contents of lib/main.dart with the following code. |
This app uses a parameter for the app title and the title shown |
on the app’s appBar. This decision simplifies the code. |
<code_start>import 'package:flutter/material.dart'; |
void main() => runApp(const MyApp()); |
class MyApp extends StatelessWidget { |
const MyApp({super.key}); |
@override |
Widget build(BuildContext context) { |
const String appTitle = 'Flutter layout demo'; |
return MaterialApp( |
title: appTitle, |
home: Scaffold( |
appBar: AppBar( |
title: const Text(appTitle), |
), |
body: const Center( |
child: Text('Hello World'), |
), |
), |
); |
} |
}<code_end> |
<topic_end> |
<topic_start> |
Add the Title section |
In this section, create a TitleSection widget that resembles |
the following layout.<topic_end> |
<topic_start> |
Add the TitleSection Widget |
Add the following code after the MyApp class. |
<code_start>class TitleSection extends StatelessWidget { |
const TitleSection({ |
super.key, |
required this.name, |
required this.location, |
}); |
final String name; |
final String location; |
@override |
Widget build(BuildContext context) { |
return Padding( |
padding: const EdgeInsets.all(32), |
child: Row( |
children: [ |
Expanded( |
/*1*/ |
child: Column( |
crossAxisAlignment: CrossAxisAlignment.start, |
children: [ |
/*2*/ |
Padding( |
padding: const EdgeInsets.only(bottom: 8), |
child: Text( |
name, |
style: const TextStyle( |
fontWeight: FontWeight.bold, |
), |
), |
), |
Text( |
location, |
style: TextStyle( |
color: Colors.grey[500], |
), |
), |
], |
), |
), |
/*3*/ |
Icon( |
Icons.star, |
color: Colors.red[500], |
), |
const Text('41'), |
], |
), |
); |
} |
}<code_end> |
<topic_end> |
<topic_start> |
Change the app body to a scrolling view |
In the body property, replace the Center widget with a |
SingleChildScrollView widget. |
Within the SingleChildScrollView widget, replace the Text widget with a |
Column widget.These code updates change the app in the following ways.<topic_end> |
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