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samples/isolate_example/lib/page_two.dart

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7.2 KiB

// Copyright 2019-present the Flutter authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'dart:isolate';
import 'dart:math';
class InfiniteProcessPageStarter extends StatelessWidget {
@override
Widget build(context) {
return ChangeNotifierProvider(
builder: (context) => InfiniteProcessIsolateController(),
child: InfiniteProcessPage(),
);
}
}
class InfiniteProcessPage extends StatelessWidget {
@override
Widget build(context) {
final controller = Provider.of<InfiniteProcessIsolateController>(context);
return Column(
mainAxisSize: MainAxisSize.min,
children: [
Padding(
child: Text(
'Summation Results',
style: Theme.of(context).textTheme.title,
),
padding: EdgeInsets.all(8),
),
Expanded(child: RunningList()),
SafeArea(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [newButtons(context)],
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Switch(
value: !controller.paused,
onChanged: (_) => controller.pausedSwitch(),
activeTrackColor: Colors.lightGreenAccent,
activeColor: Colors.black,
inactiveTrackColor: Colors.deepOrangeAccent,
inactiveThumbColor: Colors.black,
),
Text('Pause/Resume'),
],
),
radioButtonWidget(context),
],
),
),
],
);
}
}
class InfiniteProcessIsolateController extends ChangeNotifier {
Isolate newIsolate;
ReceivePort mIceRP;
SendPort newIceSP;
Capability capability;
int _currentMultiplier = 1;
List<int> _currentResults = [];
bool _running = false;
bool _paused = false;
InfiniteProcessIsolateController() {
start();
_running = true;
}
Future<void> createIsolate() async {
mIceRP = ReceivePort();
newIsolate = await Isolate.spawn(_secondIsolateEntryPoint, mIceRP.sendPort);
}
void listen() {
mIceRP.listen((dynamic message) {
if (message is SendPort) {
newIceSP = message;
newIceSP.send(_currentMultiplier);
} else if (message is int) {
setCurrentResults(message);
}
});
}
Future<void> start() async {
if (_running == false && _paused == false) {
await createIsolate();
if (newIsolate == null) return;
listen();
_running = true;
notifyListeners();
}
}
void terminate() {
newIsolate.kill();
_running = false;
_currentResults.clear();
notifyListeners();
}
void pausedSwitch() {
(_paused) ? newIsolate.resume(capability) : capability = newIsolate.pause();
_paused = !_paused;
notifyListeners();
}
void setMultiplier(int newMultiplier) {
_currentMultiplier = newMultiplier;
newIceSP.send(_currentMultiplier);
notifyListeners();
}
void setCurrentResults(int newNum) {
_currentResults.insert(0, newNum);
notifyListeners();
}
int get multiplier => _currentMultiplier;
bool get paused => _paused;
bool get running => _running;
List<int> get currentResults => _currentResults;
void dispose() {
super.dispose();
newIsolate?.kill(priority: Isolate.immediate);
newIsolate = null;
}
}
class RunningList extends StatelessWidget {
@override
Widget build(context) {
final controller = Provider.of<InfiniteProcessIsolateController>(context);
List<int> sums = controller.currentResults;
return DecoratedBox(
decoration: BoxDecoration(
color: Colors.grey[200],
),
child: ListView.builder(
itemCount: sums.length,
itemBuilder: (context, index) {
return Column(
children: [
Card(
child: ListTile(
leading: Text('${sums.length - index}.'),
title: Text('${sums[index]}.'),
),
color: (controller.running && !controller.paused)
? Colors.lightGreenAccent
: Colors.deepOrangeAccent,
),
Divider(
color: Colors.blue,
height: 3,
),
],
);
},
),
);
}
}
Future<void> _secondIsolateEntryPoint(SendPort callerSP) async {
int multiplyValue = 1;
ReceivePort newIceRP = ReceivePort();
callerSP.send(newIceRP.sendPort);
newIceRP.listen((dynamic message) {
if (message is int) multiplyValue = message;
});
int forEnd = 10000;
while (true) {
int sum = 0;
for (int i = 0; i < forEnd; i++) {
sum += await brokenUpComputation(1000);
}
forEnd += 10;
callerSP.send(sum * multiplyValue);
}
}
Future<int> brokenUpComputation(int num) {
Random rng = Random();
return Future(() {
int sum = 0;
for (int i = 0; i < num; i++) {
sum += rng.nextInt(100);
}
return sum;
});
}
Widget newButtons(BuildContext context) {
final controller =
Provider.of<InfiniteProcessIsolateController>(context, listen: false);
return ButtonBar(
alignment: MainAxisAlignment.center,
children: [
RaisedButton(
child: const Text('Start'),
elevation: 8.0,
onPressed: () => controller.start(),
),
RaisedButton(
child: const Text('Terminate'),
elevation: 8.0,
onPressed: () => controller.terminate(),
),
],
);
}
Widget radioButtonWidget(BuildContext context) {
final controller = Provider.of<InfiniteProcessIsolateController>(context);
return Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Radio(
value: 1,
groupValue: controller.multiplier,
// The following is a result of https://github.com/dart-lang/linter/issues/695
// ignore: avoid_types_on_closure_parameters
onChanged: (int _) => controller.setMultiplier(1),
),
Text('1x'),
Radio(
value: 2,
groupValue: controller.multiplier,
// ignore: avoid_types_on_closure_parameters
onChanged: (int _) => controller.setMultiplier(2),
),
Text('2x'),
Radio(
value: 3,
groupValue: controller.multiplier,
// ignore: avoid_types_on_closure_parameters
onChanged: (int _) => controller.setMultiplier(3),
),
Text('3x'),
],
);
}