Android Observable Queries not working after adding suspend word

Question

I am trying to migrate from LiveData to Kotlin Flow. Right now I am working on a project that has offline supports in Room.

I was looking through the documentation and I managed to write an observable query in coroutines with Flow. (see: here)

The problem that I am facing right now is that whenever I add the suspend keyword inside the DAO class and try to run the project, it fails with the following error:

error: Not sure how to convert a Cursor to this method's return type (kotlinx.coroutines.flow.Flow<MyModel>).

The code with the problem:

@Transaction
@Query("SELECT * FROM table WHERE status = :status LIMIT 1")
suspend fun getWithSpecificStatus(status: String): Flow<MyModel?>

I am calling the code like this:

val modelLiveData: LiveData<MyModel?> = liveData(Dispatchers.IO) {
        val result = databaseService.getWithSpecificStatus(Enum.IN_PROGRESS.status).first()

        result?.let {
            emit(it)
        }

    }

I tried to keep things simple. why is my code failing?

score 1 · Accepted Answer · answered Jun 11 '21 at 15:45

1

You could directly initialise the value of modelLiveData as:

    val modelLiveData=databaseService.
    getWithSpecificStatus(Enum.IN_PROGRESS.status).first()
    .asLiveData()

You have used Flow so asLiveData() is used to convert it to LiveData

Also suggestion , you do should not use the suspend keyword because when you are returning Flow, Room automatically does this asynchronously. You just need to consume the Flow.

answered Jun 11 '21 at 15:45

sinha-shaurya

549
5
15

So if I use .asLiveData(Dispatchers.IO) and delete the suspend keyword, this will run asynchronously? – Marian Pavel Jun 11 '21 at 15:53
It definitely will work. Also drop the Context (Dispatchers.IO), it is not required – sinha-shaurya Jun 11 '21 at 16:55

Android Observable Queries not working after adding suspend word

1 Answers1