Quarterly maintenance on isolate_example (#142)

MAINTENANCE.md

@@ -10,7 +10,7 @@ match any new language/SDK features, etc.).
 | chrome-os-best-practices  |                    |                |
 | experimental              |                    |                |
 | flutter_maps_firestore    |                    |                |
-| isolate_example           |                    |                |
+| isolate_example           | redbrogdon         | 9/12/19        |
 | jsonexample               |                    |                |
 | material_studies/shrine   |                    |                |
 | place_tracker             |                    |                |

isolate_example/.gitignore

@@ -15,8 +15,10 @@
 *.iws
 .idea/
 
-# Visual Studio Code related
+# The .vscode folder contains launch configuration and tasks you configure in
-.vscode/
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
 
 # Flutter/Dart/Pub related
 **/doc/api/
@@ -59,6 +61,7 @@
 **/ios/Flutter/app.flx
 **/ios/Flutter/app.zip
 **/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
 **/ios/ServiceDefinitions.json
 **/ios/Runner/GeneratedPluginRegistrant.*
 
@@ -67,5 +70,4 @@
 !**/ios/**/default.mode2v3
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
-!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
-bash: parse_git_branch: command not found

isolate_example/.metadata

@@ -0,0 +1,10 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: 2d2a1ffec95cc70a3218872a2cd3f8de4933c42f
+  channel: stable
+
+project_type: app

isolate_example/android/app/src/main/kotlin/dev/flutter/isolate_example/MainActivity.kt

@@ -0,0 +1,13 @@
+package dev.flutter.isolate_example
+
+import android.os.Bundle
+
+import io.flutter.app.FlutterActivity
+import io.flutter.plugins.GeneratedPluginRegistrant
+
+class MainActivity: FlutterActivity() {
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    GeneratedPluginRegistrant.registerWith(this)
+  }
+}

isolate_example/ios/Runner/AppDelegate.swift

@@ -0,0 +1,13 @@
+import UIKit
+import Flutter
+
+@UIApplicationMain
+@objc class AppDelegate: FlutterAppDelegate {
+  override func application(
+    _ application: UIApplication,
+    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+  ) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+  }
+}

isolate_example/ios/Runner/Runner-Bridging-Header.h

@@ -0,0 +1 @@
+#import "GeneratedPluginRegistrant.h"

isolate_example/lib/main.dart

@@ -15,10 +15,16 @@
 import 'package:flutter/material.dart';
 
 import 'page_one.dart';
-import 'page_two.dart';
 import 'page_three.dart';
+import 'page_two.dart';
 
-void main() => runApp(MaterialApp(home: StartApp()));
+void main() {
+  runApp(
+    MaterialApp(
+      home: StartApp(),
+    ),
+  );
+}
 
 class StartApp extends StatelessWidget {
   @override
@@ -30,9 +36,18 @@ class StartApp extends StatelessWidget {
           appBar: AppBar(
             bottom: TabBar(
               tabs: [
-                Tab(icon: Icon(Icons.flash_on), text: 'Performance'),
+                Tab(
-                Tab(icon: Icon(Icons.sync), text: 'Infinite Process'),
+                  icon: Icon(Icons.flash_on),
-                Tab(icon: Icon(Icons.storage), text: 'Data Transfer'),
+                  text: 'Performance',
+                ),
+                Tab(
+                  icon: Icon(Icons.sync),
+                  text: 'Infinite Process',
+                ),
+                Tab(
+                  icon: Icon(Icons.storage),
+                  text: 'Data Transfer',
+                ),
               ],
             ),
             title: Text('Isolate Example'),

isolate_example/lib/page_one.dart

@@ -15,6 +15,20 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 
+// Computes the nth number in the Fibonacci sequence.
+int fib(int n) {
+  int number1 = n - 1;
+  int number2 = n - 2;
+
+  if (n == 1) {
+    return 0;
+  } else if (n == 0) {
+    return 1;
+  } else {
+    return (fib(number1) + fib(number2));
+  }
+}
+
 class PerformancePage extends StatefulWidget {
   @override
   _PerformancePageState createState() => _PerformancePageState();
@@ -65,7 +79,9 @@ class _PerformancePageState extends State<PerformancePage> {
   }
 
   VoidCallback createMainIsolateCallBack(
-      BuildContext context, AsyncSnapshot snapshot) {
+    BuildContext context,
+    AsyncSnapshot snapshot,
+  ) {
     if (snapshot.connectionState == ConnectionState.done) {
       return () {
         setState(() {
@@ -101,27 +117,20 @@ class _PerformancePageState extends State<PerformancePage> {
       return null;
     }
   }
-}
 
-Future<void> computeOnMainIsolate() async {
+  Future<void> computeOnMainIsolate() async {
-  // The isolate will need a little time to disable the buttons before the performance hit.
+    // A delay is added here to give Flutter the chance to redraw the UI at least
-  await Future.delayed(Duration(milliseconds: 100), () => fib(45));
+    // once before the computation (which, since it's run on the main isolate,
-}
+    // will lock up the app) begins executing.
+    await Future.delayed(
+      Duration(milliseconds: 100),
+      () => fib(45),
+    );
+  }
 
-Future<void> computeOnSecondaryIsolate() async {
+  Future<void> computeOnSecondaryIsolate() async {
-  await compute(fib, 45);
+    // Compute the Fibonacci series on a secondary isolate.
-}
+    await compute(fib, 45);
-
-int fib(int n) {
-  int number1 = n - 1;
-  int number2 = n - 2;
-
-  if (n == 1) {
-    return 0;
-  } else if (n == 0) {
-    return 1;
-  } else {
-    return (fib(number1) + fib(number2));
   }
 }
 
@@ -133,44 +142,32 @@ class SmoothAnimationWidget extends StatefulWidget {
 class SmoothAnimationWidgetState extends State<SmoothAnimationWidget>
     with TickerProviderStateMixin {
   AnimationController _controller;
-  Animation<BorderRadius> borderRadius;
+  Animation<BorderRadius> _borderAnimation;
 
   @override
   void initState() {
     super.initState();
 
-    _controller =
+    _controller = AnimationController(
-        AnimationController(duration: const Duration(seconds: 1), vsync: this)
+      duration: const Duration(seconds: 1),
-          ..addStatusListener(
+      vsync: this,
-            (status) {
-              if (status == AnimationStatus.completed) {
-                _controller.reverse();
-              } else if (status == AnimationStatus.dismissed) {
-                _controller.forward();
-              }
-            },
-          );
-
-    borderRadius = BorderRadiusTween(
-      begin: BorderRadius.circular(100.0),
-      end: BorderRadius.circular(0.0),
-    ).animate(
-      CurvedAnimation(
-        parent: _controller,
-        curve: Curves.linear,
-      ),
     );
 
-    _controller.forward();
+    _borderAnimation = BorderRadiusTween(
+      begin: BorderRadius.circular(100.0),
+      end: BorderRadius.circular(0.0),
+    ).animate(_controller);
+
+    _controller.repeat(reverse: true);
   }
 
   @override
   Widget build(BuildContext context) {
-    return AnimatedBuilder(
+    return Center(
-      animation: borderRadius,
+      child: AnimatedBuilder(
-      builder: (context, child) {
+        animation: _borderAnimation,
-        return Center(
+        builder: (context, child) {
-          child: Container(
+          return Container(
             child: FlutterLogo(
               size: 200,
             ),
@@ -180,13 +177,16 @@ class SmoothAnimationWidgetState extends State<SmoothAnimationWidget>
             decoration: BoxDecoration(
               gradient: LinearGradient(
                 begin: Alignment.topLeft,
-                colors: [Colors.blueAccent, Colors.redAccent],
+                colors: [
+                  Colors.blueAccent,
+                  Colors.redAccent,
+                ],
               ),
-              borderRadius: borderRadius.value,
+              borderRadius: _borderAnimation.value,
             ),
-          ),
+          );
-        );
+        },
-      },
+      ),
     );
   }
 

isolate_example/lib/page_three.dart

@@ -11,9 +11,11 @@
 // 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 'dart:typed_data';
+
 import 'dart:isolate';
 import 'dart:math';
+import 'dart:typed_data';
+
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
@@ -30,6 +32,8 @@ class DataTransferPageStarter extends StatelessWidget {
 class DataTransferPage extends StatelessWidget {
   @override
   Widget build(context) {
+    final controller = Provider.of<DataTransferIsolateController>(context);
+
     return SafeArea(
       child: Column(
         mainAxisSize: MainAxisSize.min,
@@ -42,17 +46,34 @@ class DataTransferPage extends StatelessWidget {
             padding: EdgeInsets.all(8),
           ),
           LinearProgressIndicator(
-            value: Provider.of<DataTransferIsolateController>(context)
+            value: controller.progressPercent,
-                .progressPercent,
             backgroundColor: Colors.grey[200],
           ),
-          Expanded(child: RunningList()),
+          Expanded(
+            child: RunningList(),
+          ),
           Column(
-            mainAxisSize: MainAxisSize.min,
             children: [
-              Row(
+              RaisedButton(
-                mainAxisAlignment: MainAxisAlignment.center,
+                child: const Text('Transfer Data to 2nd Isolate'),
-                children: [createButtons(context)],
+                color: (controller.runningTest == 1)
+                    ? Colors.blueAccent
+                    : Colors.grey[300],
+                onPressed: () => controller.generateRandomNumbers(false),
+              ),
+              RaisedButton(
+                child: const Text('Transfer Data with TransferableTypedData'),
+                color: (controller.runningTest == 2)
+                    ? Colors.blueAccent
+                    : Colors.grey[300],
+                onPressed: () => controller.generateRandomNumbers(true),
+              ),
+              RaisedButton(
+                child: const Text('Generate on 2nd Isolate'),
+                color: (controller.runningTest == 3)
+                    ? Colors.blueAccent
+                    : Colors.grey[300],
+                onPressed: controller.generateOnSecondaryIsolate,
               ),
             ],
           ),
@@ -63,33 +84,39 @@ class DataTransferPage extends StatelessWidget {
 }
 
 class DataTransferIsolateController extends ChangeNotifier {
-  Isolate _newIsolate;
+  Isolate _isolate;
-  ReceivePort _mIceRP;
+  ReceivePort _incomingReceivePort;
-  SendPort _newIceSP;
+  SendPort _outgoingSendPort;
 
   final currentProgress = <String>[];
   int runningTest = 0;
   Stopwatch _timer = Stopwatch();
   double progressPercent = 0;
 
+  Isolate get newIsolate => _isolate;
+
+  bool get running => runningTest != 0;
+
   DataTransferIsolateController() {
     createIsolate();
     listen();
   }
 
   Future<void> createIsolate() async {
-    _mIceRP = ReceivePort();
+    _incomingReceivePort = ReceivePort();
-    _newIsolate =
+    _isolate = await Isolate.spawn(
-        await Isolate.spawn(_secondIsolateEntryPoint, _mIceRP.sendPort);
+        _secondIsolateEntryPoint, _incomingReceivePort.sendPort);
   }
 
   void listen() {
-    _mIceRP.listen((dynamic message) {
+    _incomingReceivePort.listen((dynamic message) {
-      if (message is SendPort) _newIceSP = message;
+      if (message is SendPort) {
+        _outgoingSendPort = message;
+      }
 
       if (message is int) {
         currentProgress.insert(
-            0, '$message% - ${_timer.elapsedMilliseconds / 1000} Sec');
+            0, '$message% - ${_timer.elapsedMilliseconds / 1000} seconds');
         progressPercent = message / 100;
       }
 
@@ -109,7 +136,7 @@ class DataTransferIsolateController extends ChangeNotifier {
 
     _timer = Stopwatch();
     _timer.start();
-    _newIceSP.send('start');
+    _outgoingSendPort.send('start');
 
     notifyListeners();
   }
@@ -150,26 +177,22 @@ class DataTransferIsolateController extends ChangeNotifier {
 
   Future<void> sendNumbers(dynamic numList) async {
     return Future<void>(() {
-      _newIceSP.send(numList);
+      _outgoingSendPort.send(numList);
     });
   }
 
-  Isolate get newIsolate => _newIsolate;
-
-  bool get running => runningTest != 0;
-
   void dispose() {
     super.dispose();
-    _newIsolate?.kill(priority: Isolate.immediate);
+    _isolate?.kill(priority: Isolate.immediate);
-    _newIsolate = null;
+    _isolate = null;
   }
 }
 
 class RunningList extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
-    final controller = Provider.of<DataTransferIsolateController>(context);
+    final progress =
-    final progress = controller.currentProgress;
+        Provider.of<DataTransferIsolateController>(context).currentProgress;
 
     return DecoratedBox(
       decoration: BoxDecoration(
@@ -234,7 +257,10 @@ Iterable<int> createNums() sync* {
 }
 
 Future<void> generateAndSum(
-    SendPort callerSP, Iterable<int> iter, int length) async {
+  SendPort callerSP,
+  Iterable<int> iter,
+  int length,
+) async {
   int sum = 0;
   int count = 1;
 
@@ -248,41 +274,3 @@ Future<void> generateAndSum(
 
   return sum;
 }
-
-Widget createButtons(BuildContext context) {
-  final controller =
-      Provider.of<DataTransferIsolateController>(context, listen: false);
-  return ButtonBar(
-    alignment: MainAxisAlignment.center,
-    children: [
-      Column(
-        children: [
-          RaisedButton(
-            child: const Text('Transfer Data to 2nd Isolate'),
-            elevation: 8.0,
-            color: (controller.runningTest == 1)
-                ? Colors.blueAccent
-                : Colors.grey[300],
-            onPressed: () => controller.generateRandomNumbers(false),
-          ),
-          RaisedButton(
-            child: const Text('Transfer Data with TransferableTypedData'),
-            elevation: 8.0,
-            color: (controller.runningTest == 2)
-                ? Colors.blueAccent
-                : Colors.grey[300],
-            onPressed: () => controller.generateRandomNumbers(true),
-          ),
-          RaisedButton(
-            child: const Text('Generate on 2nd Isolate'),
-            elevation: 8.0,
-            color: (controller.runningTest == 3)
-                ? Colors.blueAccent
-                : Colors.grey[300],
-            onPressed: controller.generateOnSecondaryIsolate,
-          ),
-        ],
-      ),
-    ],
-  );
-}

isolate_example/lib/page_two.dart

@@ -12,11 +12,12 @@
 // 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';
 
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
 class InfiniteProcessPageStarter extends StatelessWidget {
   @override
   Widget build(context) {
@@ -32,28 +33,40 @@ class InfiniteProcessPage extends StatelessWidget {
   Widget build(context) {
     final controller = Provider.of<InfiniteProcessIsolateController>(context);
 
-    return Column(
+    return SafeArea(
-      mainAxisSize: MainAxisSize.min,
+      child: Column(
-      children: [
+        mainAxisSize: MainAxisSize.min,
-        Padding(
+        children: [
-          child: Text(
+          Padding(
-            'Summation Results',
+            padding: const EdgeInsets.all(16.0),
-            style: Theme.of(context).textTheme.title,
+            child: Text(
+              'Summation Results',
+              style: Theme.of(context).textTheme.title,
+            ),
           ),
-          padding: EdgeInsets.all(8),
+          Expanded(
-        ),
+            child: RunningList(),
-        Expanded(child: RunningList()),
+          ),
-        SafeArea(
+          Column(
-          child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
-              Row(
+              ButtonBar(
-                mainAxisAlignment: MainAxisAlignment.center,
+                alignment: MainAxisAlignment.center,
-                children: [newButtons(context)],
+                children: [
+                  RaisedButton(
+                    child: const Text('Start'),
+                    elevation: 8.0,
+                    onPressed: () => controller.start(),
+                  ),
+                  RaisedButton(
+                    child: const Text('Terminate'),
+                    elevation: 8.0,
+                    onPressed: () => controller.terminate(),
+                  ),
+                ],
               ),
               Row(
                 mainAxisAlignment: MainAxisAlignment.center,
-                crossAxisAlignment: CrossAxisAlignment.center,
                 children: [
                   Switch(
                     value: !controller.paused,
@@ -66,11 +79,23 @@ class InfiniteProcessPage extends StatelessWidget {
                   Text('Pause/Resume'),
                 ],
               ),
-              radioButtonWidget(context),
+              Row(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: [
+                  for (int i = 1; i <= 3; i++) ...[
+                    Radio<int>(
+                      value: i,
+                      groupValue: controller.currentMultiplier,
+                      onChanged: (val) => controller.setMultiplier(val),
+                    ),
+                    Text('${i}x')
+                  ],
+                ],
+              ),
             ],
           ),
-        ),
+        ],
-      ],
+      ),
     );
   }
 }
@@ -83,9 +108,17 @@ class InfiniteProcessIsolateController extends ChangeNotifier {
 
   int _currentMultiplier = 1;
   List<int> _currentResults = [];
-  bool _running = false;
+  bool _created = false;
   bool _paused = false;
 
+  int get currentMultiplier => _currentMultiplier;
+
+  bool get paused => _paused;
+
+  bool get created => _created;
+
+  List<int> get currentResults => _currentResults;
+
   Future<void> createIsolate() async {
     mIceRP = ReceivePort();
     newIsolate = await Isolate.spawn(_secondIsolateEntryPoint, mIceRP.sendPort);
@@ -103,23 +136,28 @@ class InfiniteProcessIsolateController extends ChangeNotifier {
   }
 
   Future<void> start() async {
-    if (_running == false && _paused == false) {
+    if (_created == false && _paused == false) {
       await createIsolate();
       listen();
-      _running = true;
+      _created = true;
       notifyListeners();
     }
   }
 
   void terminate() {
     newIsolate.kill();
-    _running = false;
+    _created = false;
     _currentResults.clear();
     notifyListeners();
   }
 
   void pausedSwitch() {
-    (_paused) ? newIsolate.resume(capability) : capability = newIsolate.pause();
+    if (_paused) {
+      newIsolate.resume(capability);
+    } else {
+      capability = newIsolate.pause();
+    }
+
     _paused = !_paused;
     notifyListeners();
   }
@@ -135,18 +173,10 @@ class InfiniteProcessIsolateController extends ChangeNotifier {
     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;
+    super.dispose();
   }
 }
 
@@ -171,7 +201,7 @@ class RunningList extends StatelessWidget {
                   leading: Text('${sums.length - index}.'),
                   title: Text('${sums[index]}.'),
                 ),
-                color: (controller.running && !controller.paused)
+                color: (controller.created && !controller.paused)
                     ? Colors.lightGreenAccent
                     : Colors.deepOrangeAccent,
               ),
@@ -197,77 +227,28 @@ Future<void> _secondIsolateEntryPoint(SendPort callerSP) async {
     if (message is int) multiplyValue = message;
   });
 
-  int forEnd = 10000;
+  // This runs until the isolate is terminated.
   while (true) {
     int sum = 0;
 
-    for (int i = 0; i < forEnd; i++) {
+    for (int i = 0; i < 10000; i++) {
-      sum += await brokenUpComputation(1000);
+      sum += await doSomeWork();
     }
 
-    forEnd += 10;
     callerSP.send(sum * multiplyValue);
   }
 }
 
-Future<int> brokenUpComputation(int num) {
+Future<int> doSomeWork() {
   Random rng = Random();
 
   return Future(() {
     int sum = 0;
 
-    for (int i = 0; i < num; i++) {
+    for (int i = 0; i < 1000; 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,
-        onChanged: (dynamic _) => controller.setMultiplier(1),
-      ),
-      Text('1x'),
-      Radio(
-        value: 2,
-        groupValue: controller.multiplier,
-        onChanged: (dynamic _) => controller.setMultiplier(2),
-      ),
-      Text('2x'),
-      Radio(
-        value: 3,
-        groupValue: controller.multiplier,
-        onChanged: (dynamic _) => controller.setMultiplier(3),
-      ),
-      Text('3x'),
-    ],
-  );
-}

isolate_example/pubspec.lock

@@ -29,13 +29,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.14.11"
-  cupertino_icons:
-    dependency: "direct main"
-    description:
-      name: cupertino_icons
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.1.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -80,7 +73,7 @@ packages:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.0.0+1"
+    version: "3.1.0"
   quiver:
     dependency: transitive
     description:

isolate_example/pubspec.yaml

@@ -8,13 +8,12 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  cupertino_icons: ^0.1.2
+  provider: ^3.1.0
-  provider: ^3.0.0
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pedantic: ^1.7.0
+  pedantic: ^1.8.0+1
 
 
 flutter: