Update example (#168)

* example: pubspec: Sort.

* example: pubspec: Remove unused cupertino_icons.

* example: pubspec: Upgrade uuid 3.0.7.

* example: pubspec: Add flutter_lints 2.0.1.

* example: amalysis_options: Set linter without avoid_print which is used too many times.

* example: main: Fix non_constant_identifier_names.

* example: main: Fix prefer_interpolation_to_compose_strings.

* example: main: Rename _MyAppState to MyAppState. Fix library_private_types_in_public_api.

* example: main: Fix use_key_in_widget_constructors.

* example: main: Fix prefer_const_constructors.

* example: main: Fix use_build_context_synchronously.

Author: ryojiro

example/analysis_options.yaml

@@ -0,0 +1,5 @@
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  rules:
+    avoid_print: false

example/lib/main.dart

@@ -33,7 +33,7 @@ Future<dynamic> myBackgroundMessageHandler(Map<String, dynamic> message) {
   var uuid = payload['uuid'] as String;
   var hasVideo = payload['has_video'] == "true";
 
-  final callUUID = uuid ?? Uuid().v4();
+  final callUUID = uuid ?? const Uuid().v4();
   _callKeep.on(CallKeepPerformAnswerCallAction(),
       (CallKeepPerformAnswerCallAction event) {
     print(
@@ -99,13 +99,15 @@ Future<dynamic> myBackgroundMessageHandler(Map<String, dynamic> message) {
 }
 
 void main() {
-  runApp(MyApp());
+  runApp(const MyApp());
 }
 
 class MyApp extends StatelessWidget {
+  const MyApp({Key key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
+    return const MaterialApp(
       title: 'Welcome to Flutter',
       debugShowCheckedModeBanner: false,
       home: HomePage(),
@@ -114,8 +116,10 @@ class MyApp extends StatelessWidget {
 }
 
 class HomePage extends StatefulWidget {
+  const HomePage({Key key}) : super(key: key);
+
   @override
-  _MyAppState createState() => _MyAppState();
+  MyAppState createState() => MyAppState();
 }
 
 class Call {
@@ -125,15 +129,15 @@ class Call {
   bool muted = false;
 }
 
-class _MyAppState extends State<HomePage> {
+class MyAppState extends State<HomePage> {
   final FlutterCallkeep _callKeep = FlutterCallkeep();
   Map<String, Call> calls = {};
-  String newUUID() => Uuid().v4();
+  String newUUID() => const Uuid().v4();
   final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
 
-  void iOS_Permission() {
+  void iOSPermission() {
     _firebaseMessaging.requestNotificationPermissions(
-        IosNotificationSettings(sound: true, badge: true, alert: true));
+        const IosNotificationSettings(sound: true, badge: true, alert: true));
     _firebaseMessaging.onIosSettingsRegistered
         .listen((IosNotificationSettings settings) {
       print('Settings registered: $settings');
@@ -261,7 +265,7 @@ class _MyAppState extends State<HomePage> {
     });
     print('Display incoming call now');
     final bool hasPhoneAccount = await _callKeep.hasPhoneAccount();
-    if (!hasPhoneAccount) {
+    if (!hasPhoneAccount && context.mounted) {
       await _callKeep.hasDefaultPhoneAccount(context, <String, dynamic>{
         'alertTitle': 'Permissions required',
         'alertDescription':
@@ -333,7 +337,7 @@ class _MyAppState extends State<HomePage> {
       //  _firebaseMessaging.requestNotificationPermissions();
 
       _firebaseMessaging.getToken().then((token) {
-        print('[FCM] token => ' + token);
+        print('[FCM] token => $token');
       });
 
       _firebaseMessaging.configure(
@@ -346,7 +350,7 @@ class _MyAppState extends State<HomePage> {
             var callerName = payload['caller_name'] as String;
             var uuid = payload['uuid'] as String;
             var hasVideo = payload['has_video'] == "true";
-            final callUUID = uuid ?? Uuid().v4();
+            final callUUID = uuid ?? const Uuid().v4();
             setState(() {
               calls[callUUID] = Call(callerId);
             });

example/pubspec.yaml

@@ -4,15 +4,12 @@ version: 0.1.1
 
 # The following line prevents the package from being accidentally published to
 # pub.dev using `pub publish`. This is preferred for private packages.
-publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+publish_to: "none" # Remove this line if you wish to publish to pub.dev
 
 environment:
   sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
-  flutter:
-    sdk: flutter
-
   callkeep:
     # When depending on this package from a real application you should use:
     #   callkeep: ^x.y.z
@@ -21,13 +18,13 @@ dependencies:
     # the parent directory to use the current plugin's version.
     path: ../
 
-  # The following adds the Cupertino Icons font to your application.
-  # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^1.0.0
-  uuid: ^2.0.2
   firebase_messaging: ^7.0.0
+  flutter:
+    sdk: flutter
+  uuid: ^3.0.7
 
 dev_dependencies:
+  flutter_lints: ^2.0.1
   flutter_test:
     sdk: flutter
 
@@ -36,7 +33,6 @@ dev_dependencies:
 
 # The following section is specific to Flutter.
 flutter:
-
   # The following line ensures that the Material Icons font is
   # included with your application, so that you can use the icons in
   # the material Icons class.

example/test/widget_test.dart

@@ -12,7 +12,7 @@ import 'package:flutter_test/flutter_test.dart';
 void main() {
   testWidgets('Verify Platform version', (WidgetTester tester) async {
     // Build our app and trigger a frame.
-    await tester.pumpWidget(MyApp());
+    await tester.pumpWidget(const MyApp());
 
     // Verify that platform version is retrieved.
     expect(