Hey, I have a login fun and I want it to wait for ...

# android

[Nikola Milovic]

Hey, I have a login fun and I want it to wait for .signInWithEmail.. to finish and then based on it's result, to do something and return a TaskResult. Now the problem is that the onCompleteListener doesn't happen before the last return. Is there a way to wait for its completion? I looked into .async and .await but didn't find any useful docs. If anyone can point me in the right direction it would be appreciated. (this is in my RemoteDataSource and the Repository calls the Login fun)

fun Login(email: String, password: String): TaskResult {
         var taskResult = TaskResult.LOADING

          firebaseAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener { 
              if(it.isSuccessful){
                  taskResult = TaskResult.SUCCESS
              }
          }

         return taskResult // THIS TRIGGERS BEFORE THE ONCOMPLETELISTENER, so I always get TaskResult.Loading back
     }

I am also looking to run this in a coroutine

[Richard Phol]

You can use Continuation with suspendCoroutine :

suspend fun login(...): TaskResult = suspendCoroutine { cont ->
        firebaseAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener {
            if (it.isSuccessful) {
                taskResult = TaskResult.SUCCESS
                cont.resume(taskResult)
            }
        }
    }

[Adam Powell]

you'll probably want to use suspendCancellableCoroutine so that you can resume things based on job cancellation; firebase Task doesn't support cancelling the actual work but you can clean up your own code at least

[Nikola Milovic]

Thanks! I will look into it, didn't know about this.

[Adam Powell]

(slight correction: Task itself doesn't support it but some rare firebase operations support passing a cancellation token forward and you can wire that up to the coroutines cancellation mechanism when it's available. It's not very consistent.)