Using functions instead of classes for permission observers

Author: emawby

example/lib/main.dart

@@ -14,7 +14,6 @@ class MyApp extends StatefulWidget {
 class _MyAppState extends State<MyApp>
     with
         OneSignalPushSubscriptionObserver,
-        OneSignalPermissionObserver,
         OneSignalNotificationLifecycleListener,
         OneSignalNotificationClickListener {
   String _debugLabelString = "";
@@ -52,7 +51,11 @@ class _MyAppState extends State<MyApp>
     OneSignal.Notifications.clearAll();
 
     OneSignal.User.pushSubscription.addObserver(this);
-    OneSignal.Notifications.addPermissionObserver(this);
+
+    OneSignal.Notifications.addPermissionObserver((state) {
+      print("Has permission " + state.toString());
+    });
+
     OneSignal.Notifications.addClickListener(this);
     OneSignal.Notifications.addLifecycleListener(this);
     OneSignal.InAppMessages.addClickListener((event) {
@@ -90,10 +93,6 @@ class _MyAppState extends State<MyApp>
     OneSignal.InAppMessages.paused(false);
   }
 
-  void onNotificationPermissionDidChange(bool state) {
-    print("Has permission " + state.toString());
-  }
-
   void onOSPushSubscriptionChange(OSPushSubscriptionChangedState state) {
     print(OneSignal.User.pushSubscription.optedIn);
     print(OneSignal.User.pushSubscription.id);

lib/src/notifications.dart

@@ -5,6 +5,8 @@ import 'package:onesignal_flutter/src/defines.dart';
 import 'package:onesignal_flutter/src/notification.dart';
 import 'package:onesignal_flutter/src/permission.dart';
 
+typedef void OnNotificationPermissionChangeObserver(bool permission);
+
 class OneSignalNotificationLifecycleListener {
   void onWillDisplayNotification(OSNotificationWillDisplayEvent event) {}
 }
@@ -23,8 +25,8 @@ class OneSignalNotifications {
   // private channels used to bridge to ObjC/Java
   MethodChannel _channel = const MethodChannel('OneSignal#notifications');
 
-  List<OneSignalPermissionObserver> _observers =
-      <OneSignalPermissionObserver>[];
+  List<OnNotificationPermissionChangeObserver> _observers =
+      <OnNotificationPermissionChangeObserver>[];
   // constructor method
   OneSignalNotifications() {
     this._channel.setMethodCallHandler(_handleMethod);
@@ -108,12 +110,13 @@ class OneSignalNotifications {
   /// The OSNotificationPermissionObserver.onNotificationPermissionDidChange method will be fired on the passed-in object
   /// when a notification permission setting changes. This happens when the user enables or disables
   /// notifications for your app from the system settings outside of your app.
-  void addPermissionObserver(OneSignalPermissionObserver observer) {
+  void addPermissionObserver(OnNotificationPermissionChangeObserver observer) {
     _observers.add(observer);
   }
 
   // Remove a push subscription observer that has been previously added.
-  void removePermissionObserver(OneSignalPermissionObserver observer) {
+  void removePermissionObserver(
+      OnNotificationPermissionChangeObserver observer) {
     _observers.remove(observer);
   }
 
@@ -145,7 +148,7 @@ class OneSignalNotifications {
 
   void onNotificationPermissionDidChange(bool permission) {
     for (var observer in _observers) {
-      observer.onNotificationPermissionDidChange(permission);
+      observer(permission);
     }
   }
 
@@ -180,7 +183,3 @@ class OneSignalNotifications {
     _clickListeners.remove(listener);
   }
 }
-
-class OneSignalPermissionObserver {
-  void onNotificationPermissionDidChange(bool permission) {}
-}