text
stringlengths
1
372
for further details on internationalization and localization in flutter,
see the internationalization guide, which has sample code
with and without the intl package.
<topic_end>
<topic_start>
managing dependencies
in iOS, you add dependencies with CocoaPods by adding to your podfile.
flutter uses dart’s build system and the pub package manager
to handle dependencies. the tools delegate the building of the
native android and iOS wrapper apps to the
respective build systems.
while there is a podfile in the iOS folder in your
flutter project, only use this if you are adding native
dependencies needed for per-platform integration.
in general, use pubspec.yaml to declare external dependencies in flutter.
a good place to find great packages for flutter is on pub.dev.
<topic_end>
<topic_start>
ViewControllers
this section of the document discusses the equivalent
of ViewController in flutter and how to listen to
lifecycle events.
<topic_end>
<topic_start>
equivalent of ViewController in flutter
in UIKit, a ViewController represents a portion of user interface,
most commonly used for a screen or section.
these are composed together to build complex user interfaces,
and help scale your application’s UI.
in flutter, this job falls to widgets.
as mentioned in the navigation section,
screens in flutter are represented by widgets since
“everything is a widget!”
use a navigator to move between different routes
that represent different screens or pages,
or maybe different states or renderings of the same data.
<topic_end>
<topic_start>
listening to lifecycle events
in UIKit, you can override methods to the ViewController
to capture lifecycle methods for the view itself,
or register lifecycle callbacks in the AppDelegate.
in flutter, you have neither concept, but you can instead
listen to lifecycle events by hooking into
the WidgetsBinding observer and listening to
the didChangeAppLifecycleState() change event.
the observable lifecycle events are:
for more details on the meaning of these states, see
AppLifecycleState documentation.
<topic_end>
<topic_start>
layouts
this section discusses different layouts in flutter
and how they compare with UIKit.
<topic_end>
<topic_start>
displaying a list view
in UIKit, you might show a list in
either a UITableView or a UICollectionView.
in flutter, you have a similar implementation using a ListView.
in UIKit, these views have delegate methods
for deciding the number of rows,
the cell for each index path, and the size of the cells.
due to flutter’s immutable widget pattern,
you pass a list of widgets to your ListView,
and flutter takes care of making sure that
scrolling is fast and smooth.
<code_start>
import 'package:flutter/material.dart';
void main() {
runApp(const SampleApp());
}
class SampleApp extends StatelessWidget {
const SampleApp({super.key});
// this widget is the root of your application.
@override
widget build(BuildContext context) {
return const MaterialApp(
title: 'sample app',
home: SampleAppPage(),
);
}
}
class SampleAppPage extends StatefulWidget {
const SampleAppPage({super.key});
@override
State<SampleAppPage> createState() => _SampleAppPageState();
}
class _SampleAppPageState extends State<SampleAppPage> {
List<Widget> _getListData() {
final List<Widget> widgets = [];
for (int i = 0; i < 100; i++) {
widgets.add(Padding(
padding: const EdgeInsets.all(10),
child: Text('Row $i'),
));
}
return widgets;
}
@override