NotificationHandler | A Swift notification handler | Reactive Programming library

I am trying to implement notifications for my app, but when initializing notifications FirebaseMessaging.onBackgroundMessage(notificationHandler)gives error

Error:

E/flutter (28265): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Null check operator used on a null value E/flutter (28265): #0 MethodChannelFirebaseMessaging.registerBackgroundMessageHandler (package:firebase_messaging_platform_interface/src/method_channel/method_channel_messaging.dart:173:53) E/flutter (28265): #1 FirebaseMessagingPlatform.onBackgroundMessage= (package:firebase_messaging_platform_interface/src/platform_interface/platform_interface_messaging.dart:108:16) E/flutter (28265): #2 FirebaseMessaging.onBackgroundMessage (package:firebase_messaging/src/messaging.dart:100:31)

notificationHandler:

I am using WebView to turn my responsive website into a native app. Almost everything seems to be working, but the one thing I cannot get to work is my "Login with Facebook" and "Login with Google" buttons. Google One Tap Sign-in works fine by the way (after the WebView app has logged in to Google on a different page, i.e. Gmail), but the "Login with Facebook" and "Login with Google" buttons don't work. Please note that I have in fact configured my intent correctly (i.e. any returnURL or callbackURL with my domain name that would get called, would still be called through the app), but I believe these login API's from both Google and Facebook don't return the user to any returnURL, but rather just pass their results back to the javascript that initially opened the login popup.

The problem is the following (I think): At first, both buttons opened the link in a separate browser window (Chrome). When I complete the sign-in process (with either Google or Facebook), this browser window is closed automatically, but nothing is returned to my app (thus, my app doesn't know the user completed the OAuth process). So I decided to set webSettings.setSupportMultipleWindows(false). This at least fixed my problem with the Instagram API (because that also wasn't working), and it does also make the Google and Facebook authentication windows now open within the app (so I think I'm a little closer to getting this to work), but the problem is, the return data/result from the OAuth process is still not returned to my app. In fact, the Facebook login screen manages to close my app entirely once it completes (I guess the window.close() affects my WebView app as well, or something like that). For Google on the other hand, after signing in, the page stays white. Pressing back does allow me to go back to my app's Login screen.

Here are examples of what's happening:

Facebook:

Google (first time, the login process works, but after completing the signing in, we end up with the same white page as below):

Google (every time after that, once you're signed in to Google):

The javascript that handles the response in the website version of my app all works just fine! It captures the result from the OAuth call to Google or Facebook and handles the returned e-mail address and Google/Facebook ID's, and then logs the user in to my app.

My problem is probably related to: Android Google login not working inside WebView

But I couldn't get that to work. If anyone has a better understanding of this WebView technique or knows how to apply the solution mentioned in that topic to my situation, any help would be greatly appreciated!

I've also read: Google sign in not working android webview app

And several people in that topic have stated that I have to override the popup handling, but I have no idea how to do that...

Here's my MainActivity file:

The notification appears in 2 devices(Xiaomi, Vivo) both >26 SDK. But it doesnt show up on my Samsung device which is also >26.

This is how i implemented the notification

having a bit of trouble with the following.

I have a List in a VStack as follows:

Let me explain the whole thing, just in case. I'm using BottomNavigationView with Jetpack's Mobile Navigation graphs and so. I reimplemented the method:

NavigationUI.setupWithNavController(...)

during navigation setup, instead of using this method I made a very similar:

customSetupWithNavController(...)

the only changes I made was to change de default fading transition between fragments, and started to using more natural (in my opinion) side slide animations, just like this in onNavDestinationSelected:

I am seeing some strange behaviour on a Pixel 4XL (Android 11). My foreground service's onTaskRemoved is being called unexpectedly. This doesn't occur on any other devices but I don't have any other Android 11 devices and the emulator can't do BLE.

My app uses an ongoing BLE connection to communicate with another non-android device. A foreground service is used to ensure the program remains active to receive BLE communications from the device.

It doesn't always happen but in most cases (75% of the time) after pressing home (swiping up from the bottom of the screen on a Pixel 4XL) this will cause the foreground service's onTaskRemoved to be called.

Opening a different activity in my app (i.e. an activity other than MainActivity) is almost guaranteed to make this occur.

Opening settings from the notification bar then swiping home still triggers this to occur, so it can't be that I'm accidentally killing the app since I'm swiping up when the settings app is in focus.

From my understanding, this method is only supposed to be triggered when the user terminates the app by swiping it in the task switcher.

If I go back to the task switcher, after the service was killed, my app is still available and showing the last activity opened and it's state. Switching to it resumes to the correct place, so the app itself must not have been terminated. The phone is plugged in an charging so it shouldn't be and doze/sleeping functions. This can occur within 60 seconds of launching the app, it's not a 30 minute thing.

What on earth could be going on here? The only thing I can think of is that it's not considered a foreground service for some reason. There are no errors in logcat at or around the time of the onTaskRemoved. I am not calling onTaskRemoved myself anywhere in code.

I've tried following the dumpsys in this post but it seems to be different and I couldn't find any of the references mentioned.

The notification itself is listed like this:

I have implemented background notifications using this article: Click Here To View The Article

It sets the notification for future time. But it sets only one notification i want to set multiple notifications. And also sometimes it doesn't show the notification on the time that i have set and it shows when i open the app.

Here is my Activity code:

I am currently trying to get data out of my Room Database without using a ViewModel. This is because I am working on a NotificationHandler which can be triggered at any point by an Alarm Manager.

Below is my code so far. This code below starts with a call to sortNotification from another class. sortNotification then calls launchAsyncTask which inturn goes off to the database by calling getQuotesFromDatabase. I then wait for the results (I believe), assign the data from the database to listOfQuotes variable, then call displayNotification to use it. My issue is, listOfQuotes is always null when I am trying to use it displayNotification.

Now I know the database has content as when I open my application and go to an Activity which has a ViewModel, the data is retrieved successfully. I think my issue is likely to be with the async task not completing properly or with my coroutineScope. I just need listOfQuotes to have data when the code gets into displayNotification. Any help would be greatly appreciated. Thanks in advance.

On my work, we've been using this service below to subscribe and emit notifications right and fourth. As a junior developer I already understand Input and Outputs of Angular and sort of how Emitters work.

But this service simplys confuse me. The dev who made this service already left the company and since this code is almost a boilerplate for all projects, I cannot ask him how exactly it works.

specifically this line: private static emitters: { [notificationName: string]: EventEmitter } = {}