Designed to extend part of OneSignalAPI module of the official OneSignal Plugin.

Extended Feature:

- Headings addition in Notification.

- Android Background Image (cannot use with action buttons and big picure; small icon and large icon is not displayed, must be baked into background image itself)

https://documentation.onesignal.com/docs/android-customizations

- Android Channel Id: can be used to set sound on Android push notification etc. (read more in documentation) and Notification LED color.

- Android Accent Color: to gave accent color in Action Buttons and also small_icon (if alpha channel exists)

- More to come if I had time (if you want to help, please apply for Team)

I mostly only extend Android functionality because I only have Android device.

Limitation:

Original SendPushNotificationToUserid cannot be extended since it read private entity inside original OneSignalAPI.

So I change the method by using OneSignal's external user id feature to implement SendPushNotificationToUserid.

How to use:

1. Uncheck dependencies from original OneSignalAPI (All PushNotifications folder)

2. Add dependency from OneSignalAPI_Ext

3. Do the usual OneSignal Plugin configuration

4. Call SetExternalUserId client action after calling RegisterWithUser, it will set external user id in OneSignal

Set AsyncRegistration = false in RegisterWithUser, to make sure registration already finished before calling SetExternalUserId

5. Call RemoveExternalUserId client action on Logout, before calling OneSignal Plugin's Unregister

6. Use SendPushNotificationToUserid or other methods.