Fix notification parsing

* Fix OSNotification creation with additional data under Android
* Fix OSNotification creation with background image titleTextColor not being initialize correctly
* Fix OSNotification jsonRepresentation method

Author: Jeasmine

android/src/main/java/com/onesignal/flutter/OneSignalSerializer.java

@@ -143,10 +143,9 @@ static HashMap<String, Object> convertNotificationToMap(OSNotification notificat
         if (notification.getCollapseId() != null)
             hash.put("collapseId", notification.getCollapseId());
         hash.put("priority", notification.getPriority());
-        if (notification.getAdditionalData() != null)
-            hash.put("additionalData", notification.getAdditionalData());
-
-        if (notification.getActionButtons() != null) {
+        if (notification.getAdditionalData() != null && notification.getAdditionalData().length() > 0)
+            hash.put("additionalData", convertJSONObjectToHashMap(notification.getAdditionalData()));
+        if (notification.getActionButtons() != null && !notification.getActionButtons().isEmpty()) {
             ArrayList<HashMap> buttons = new ArrayList<>();
 
             List<OSNotification.ActionButton> actionButtons = notification.getActionButtons();
@@ -168,7 +167,7 @@ static HashMap<String, Object> convertNotificationToMap(OSNotification notificat
 
         hash.put("rawPayload", notification.getRawPayload());
 
-        Log.d("onesignal", "Created json raw payload: " + convertJSONObjectToHashMap(new JSONObject(notification.getRawPayload())).toString());
+        Log.d("onesignal", "Created json raw payload: " + hash.toString());
 
         return hash;
     }
@@ -235,7 +234,7 @@ private static HashMap<String, Object> convertAndroidBackgroundImageLayoutToMap(
 
         hash.put("image", layout.getImage());
         hash.put("bodyTextColor", layout.getBodyTextColor());
-        hash.put("titleTextColor", layout.getBodyTextColor());
+        hash.put("titleTextColor", layout.getTitleTextColor());
 
         return hash;
     }

lib/src/notification.dart

@@ -171,7 +171,6 @@ class OSNotification extends JSONStringRepresentable {
 
   //converts JSON map to OSNotification instance
   OSNotification(Map<String, dynamic> json) {
-
     // iOS Specific Parameters
     if (json.containsKey('contentAvailable'))
       this.contentAvailable = json['contentAvailable'] as bool?;
@@ -386,7 +385,7 @@ class OSNotificationReceivedEvent extends JSONStringRepresentable {
 
   String jsonRepresentation() {
     return convertToJsonString({
-      'notification': this.notification.jsonRepresentation
+      'notification': this.notification.jsonRepresentation()
     });
   }
 }