text
stringlengths 1
474
|
---|
'/b': (context) => const MyPage(title: 'page B'),
|
'/c': (context) => const MyPage(title: 'page C'),
|
},
|
));
|
}<code_end>
|
Navigate to a route by pushing its name to the Navigator.
|
<code_start>Navigator.of(context).pushNamed('/b');<code_end>
|
The other popular use-case for Intents is to call external components such
|
as a Camera or File picker. For this, you would need to create a native platform
|
integration (or use an existing plugin).To learn how to build a native platform integration,
|
see developing packages and plugins.<topic_end>
|
<topic_start>
|
How do I handle incoming intents from external applications in Flutter?
|
Flutter can handle incoming intents from Android by directly talking to the
|
Android layer and requesting the data that was shared.The following example registers a text share intent filter on the native
|
activity that runs our Flutter code, so other apps can share text with
|
our Flutter app.The basic flow implies that we first handle the shared text data on the
|
Android native side (in our Activity), and then wait until Flutter requests
|
for the data to provide it using a MethodChannel.First, register the intent filter for all intents in AndroidManifest.xml:Then in MainActivity, handle the intent, extract the text that was
|
shared from the intent, and hold onto it. When Flutter is ready to process,
|
it requests the data using a platform channel, and it’s sent
|
across from the native side:Finally, request the data from the Flutter side
|
when the widget is rendered:
|
<code_start>import 'package:flutter/material.dart';
|
import 'package:flutter/services.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 MaterialApp(
|
title: 'Sample Shared App Handler',
|
theme: ThemeData(
|
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
|
),
|
home: const SampleAppPage(),
|
);
|
}
|
}
|
class SampleAppPage extends StatefulWidget {
|
const SampleAppPage({super.key});
|
@override
|
State<SampleAppPage> createState() => _SampleAppPageState();
|
}
|
class _SampleAppPageState extends State<SampleAppPage> {
|
static const platform = MethodChannel('app.channel.shared.data');
|
String dataShared = 'No data';
|
@override
|
void initState() {
|
super.initState();
|
getSharedText();
|
}
|
@override
|
Widget build(BuildContext context) {
|
return Scaffold(body: Center(child: Text(dataShared)));
|
}
|
Future<void> getSharedText() async {
|
var sharedData = await platform.invokeMethod('getSharedText');
|
if (sharedData != null) {
|
setState(() {
|
dataShared = sharedData;
|
});
|
}
|
}
|
}<code_end>
|
<topic_end>
|
<topic_start>
|
What is the equivalent of startActivityForResult()?
|
The Navigator class handles routing in Flutter and is used to get
|
a result back from a route that you have pushed on the stack.
|
This is done by awaiting on the Future returned by push().For example, to start a location route that lets the user select
|
their location, you could do the following:
|
<code_start>Object? coordinates = await Navigator.of(context).pushNamed('/location');<code_end>
|
And then, inside your location route, once the user has selected their location
|
you can pop the stack with the result:
|
<code_start>Navigator.of(context).pop({'lat': 43.821757, 'long': -79.226392});<code_end>
|
<topic_end>
|
<topic_start>
|
Async UI
|
<topic_end>
|
<topic_start>
|
What is the equivalent of runOnUiThread() in Flutter?
|
Dart has a single-threaded execution model, with support for Isolates
|
(a way to run Dart code on another thread), an event loop, and
|
asynchronous programming. Unless you spawn an Isolate, your Dart code
|
runs in the main UI thread and is driven by an event loop. Flutter’s event
|
loop is equivalent to Android’s main Looper—that is, the Looper that
|
is attached to the main thread.Dart’s single-threaded model doesn’t mean you need to run everything as a
|
blocking operation that causes the UI to freeze. Unlike Android, which
|
requires you to keep the main thread free at all times, in Flutter,
|
use the asynchronous facilities that the Dart language provides, such as
|
async/await, to perform asynchronous work. You might be familiar with
|
the async/await paradigm if you’ve used it in C#, Javascript, or if you
|
have used Kotlin’s coroutines.For example, you can run network code without causing the UI to hang by
|
using async/await and letting Dart do the heavy lifting:
|
<code_start>Future<void> loadData() async {
|
var dataURL = Uri.parse('https://jsonplaceholder.typicode.com/posts');
|
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