Hello guys! is there another way to return a value from a Coroutine without blocking the Main Thread...

# coroutines

[Wilson Castiblanco]

Hello guys! is there another way to return a value from a Coroutine without blocking the Main Thread? Maybe using Channels or Flow? . I'm getting an object from Room and I want to return a specific attribute from that object after get it.

[streetsofboston]

Using coroutines allows you not to block the main thread. Do you have a sample/snippet?

[Wilson Castiblanco]

fun getDescription(code: String): String = runBlocking {
    val tour = localRepository.getTourByCode(code) // This is a Coroutine getting the Object from Room
    return@runBlocking tour.description
}

This is the snippet, is pretty simple.

Yeah, I don't want to block the Main Thread, but, the process seems to be synchronous.

[streetsofboston]

That is because of runBlocking. Don’t use this.
Let me whip up a quick example based on your snippet…

[Wilson Castiblanco]

If I send a context Dispatchers.IO to the runBlocking that will prevent to block the Main Thread? 🤔

[Wilson Castiblanco]

Thanks @streetsofboston, yeah, exactly, but, to be able to return a value the function getDescription(..) should be synchronous, correct me if I'm wrong.

[streetsofboston]

class MyActivity: AppCompatActivity(), CoroutineScope by MainScope() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        ...
        launch { 
            textView.text = getDescription("Desc")
        }
    }
    
    suspend fun getDescription(code: String): String {
        val tour = withContext(<http://Dispatchers.IO|Dispatchers.IO>) { localRepository.getTourByCode(code) }
        return tour.description
    }

    override fun onDestroy() {
        super.onDestroy()
        cancel()
    }
}