text
stringlengths 1
474
|
---|
}
|
Widget getRow(int i) {
|
return Padding(
|
padding: const EdgeInsets.all(10),
|
child: Text("Row ${widgets[i]["title"]}"),
|
);
|
}
|
Future<void> loadData() async {
|
ReceivePort receivePort = ReceivePort();
|
await Isolate.spawn(dataLoader, receivePort.sendPort);
|
// The 'echo' isolate sends its SendPort as the first message.
|
SendPort sendPort = await receivePort.first;
|
List msg = await sendReceive(
|
sendPort,
|
'https://jsonplaceholder.typicode.com/posts',
|
);
|
setState(() {
|
widgets = msg;
|
});
|
}
|
// The entry point for the isolate.
|
static Future<void> dataLoader(SendPort sendPort) async {
|
// Open the ReceivePort for incoming messages.
|
ReceivePort port = ReceivePort();
|
// Notify any other isolates what port this isolate listens to.
|
sendPort.send(port.sendPort);
|
await for (var msg in port) {
|
String data = msg[0];
|
SendPort replyTo = msg[1];
|
String dataURL = data;
|
http.Response response = await http.get(Uri.parse(dataURL));
|
// Lots of JSON to parse
|
replyTo.send(jsonDecode(response.body));
|
}
|
}
|
Future sendReceive(SendPort port, msg) {
|
ReceivePort response = ReceivePort();
|
port.send([msg, response.sendPort]);
|
return response.first;
|
}
|
}<code_end>
|
<topic_end>
|
<topic_start>
|
What is the equivalent of OkHttp on Flutter?
|
Making a network call in Flutter is easy when you use the
|
popular http package.While the http package doesn’t have every feature found in OkHttp,
|
it abstracts away much of the networking that you would normally implement
|
yourself, making it a simple way to make network calls.To add the http package as a dependency, run flutter pub add:To make a network call, call await on the async function http.get():
|
<code_start>import 'dart:developer' as developer;
|
import 'package:http/http.dart' as http;
|
Future<void> loadData() async {
|
var dataURL = Uri.parse('https://jsonplaceholder.typicode.com/posts');
|
http.Response response = await http.get(dataURL);
|
developer.log(response.body);
|
}<code_end>
|
<topic_end>
|
<topic_start>
|
How do I show the progress for a long-running task?
|
In Android you would typically show a ProgressBar view in your UI while
|
executing a long-running task on a background thread.In Flutter, use a ProgressIndicator widget.
|
Show the progress programmatically by controlling when it’s rendered
|
through a boolean flag. Tell Flutter to update its state before your
|
long-running task starts, and hide it after it ends.In the following example, the build function is separated into three different
|
functions. If showLoadingDialog is true (when widgets.isEmpty),
|
then render the ProgressIndicator. Otherwise, render the
|
ListView with the data returned from a network call.
|
<code_start>import 'dart:convert';
|
import 'package:flutter/material.dart';
|
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 MaterialApp(
|
title: 'Sample App',
|
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> {
|
List widgets = [];
|
@override
|
void initState() {
|
super.initState();
|
loadData();
|
}
|
Widget getBody() {
|
bool showLoadingDialog = widgets.isEmpty;
|
if (showLoadingDialog) {
|
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