Kotlin Coroutines - How to block to await/join all jobs?

Question

I am new to Kotlin/Coroutines, so hopefully I am just missing something/don\'t fully understand how to structure my code for the problem I am trying to solve.

Essen

Answer 1

runBlocking blocks current thread interruptibly until its completion. I guess it's not what you want. If I think wrong and you want to block the current thread than you can get rid of coroutine and just make network call in the current thread:

val lstOfReturnData = mutableListOf()
lstInputs.forEach {
    lstOfReturnData.add(networkCallToGetData(it))
} 

---

But if it is not your intent you can do the following:

class Presenter(private val uiContext: CoroutineContext = Dispatchers.Main) 
    : CoroutineScope {

    // creating local scope for coroutines
    private var job: Job = Job()
    override val coroutineContext: CoroutineContext
        get() = uiContext + job

    // call this to cancel job when you don't need it anymore
    fun detach() {
        job.cancel()
    }

    fun processData(lstInputs: List) {

        launch {
            val deferredList = lstInputs.map { 
                async(Dispatchers.IO) { networkCallToGetData(it) } // runs in parallel in background thread
            }
            val lstOfReturnData = deferredList.awaitAll() // waiting while all requests are finished without blocking the current thread

            // use lstOfReturnData in Main Thread, e.g. update UI
        }
    }
}