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import 'package:http/http.dart' as http;
void main() {
runApp(const SampleApp());
}
class SampleApp extends StatelessWidget {
const SampleApp({super.key});
@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<Map<String, dynamic>> data = <Map<String, dynamic>>[];
@override
void initState() {
super.initState();
loadData();
}
bool get showLoadingDialog => data.isEmpty;
Future<void> loadData() async {
final Uri dataURL = Uri.parse('https://jsonplaceholder.typicode.com/posts');
final http.Response response = await http.get(dataURL);
setState(() {
data = jsonDecode(response.body);
});
}
Widget getBody() {
if (showLoadingDialog) {
return getProgressDialog();
}
return getListView();
}
Widget getProgressDialog() {
return const Center(child: CircularProgressIndicator());
}
ListView getListView() {
return ListView.builder(
itemCount: data.length,
itemBuilder: (context, index) {
return getRow(index);
},
);
}
Widget getRow(int i) {
return Padding(
padding: const EdgeInsets.all(10),
child: Text("Row ${data[i]["title"]}"),
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Sample App'),
),
body: getBody(),
);
}
}<code_end>
<topic_end>
<topic_start>Flutter for React Native developers
This document is for React Native (RN) developers looking to apply their
existing RN knowledge to build mobile apps with Flutter. If you understand
the fundamentals of the RN framework then you can use this document as a
way to get started learning Flutter development.This document can be used as a cookbook by jumping around and finding
questions that are most relevant to your needs.<topic_end>
<topic_start>
Introduction to Dart for JavaScript Developers (ES6)
Like React Native, Flutter uses reactive-style views. However, while RN
transpiles to native widgets, Flutter compiles all the way to native code.
Flutter controls each pixel on the screen, which avoids performance problems
caused by the need for a JavaScript bridge.Dart is an easy language to learn and offers the following features:A few examples of the differences between JavaScript and Dart are described
below.<topic_end>
<topic_start>
Entry point
JavaScript doesn’t have a pre-defined entry
function—you define the entry point.In Dart, every app must have a top-level main() function that serves as the
entry point to the app.
<code_start>/// Dart
void main() {}<code_end>
Try it out in DartPad.<topic_end>
<topic_start>
Printing to the console
To print to the console in Dart, use print().
<code_start>/// Dart
print('Hello world!');<code_end>
Try it out in DartPad.<topic_end>
<topic_start>
Variables
Dart is type safe—it uses a combination of static type checking
and runtime checks to ensure that a variable’s value always matches
the variable’s static type. Although types are mandatory,