i'm trying to implement the background worker in `...

# multiplatform

[Robert Munro]

i'm trying to implement the background worker in iosMain
https://medium.com/mobil-dev/background-task-with-bgtaskscheduler-1d49e22b1519

I seem to be able to get the BGTaskScheduler fine but i cant import the Operation class needed to schedule the actual work. would it be named differently? or access the operationQueue.

override fun createBatchAndAppendBoxesToIt(
    localBatchId: String,
    batchTimestamp: Long,
    batchName: String,
    boxes: List<LocalBox>
) {
    val identifier = createUniqueWorkName(localBatchId)
    BGTaskScheduler.sharedScheduler.registerForTaskWithIdentifier(identifier, null) { task ->
        val request = BGAppRefreshTaskRequest(identifier)
        request.earliestBeginDate = null
        try {
            // what's this do? pointer for submitError? CPointer<ObjCObjectVar<NSError?>>?
            BGTaskScheduler.sharedScheduler.submitTaskRequest(request, null)
        } catch (e: Exception) {
            Logger.error(TAG, "Could not schedule app refresh", e)
        }
        val operation = CreateBatchWorker() // should inherit from Operation
        //task!!.expirationHandler = { operation.cancel() }
        //operation.completionBlock = { task.setTaskCompleted(!operation.isCancelled) }
        //operationQueue.addOperation(operation)

    }
}

Would it be better to make an interface and implement it in swift? not sure

[Robert Munro]

not sure if that example is good

[Anvith]

Most likely you’re doing this on a simulator, to fetch the actual error consider using this

memScoped {
 val error = interpretCPointer<ObjCObjectVar<NSError?>>(alloc(1,1).rawPtr)
 isScheduled = BGTaskScheduler.sharedScheduler.submitTaskRequest(request, error)
 logD("Submitted background task $isScheduled, ${error?.get(0)?.value}")                   
}

relevant imports

import kotlinx.cinterop.BetaInteropApi
import kotlinx.cinterop.ExperimentalForeignApi
import kotlinx.cinterop.ObjCObjectVar
import kotlinx.cinterop.get
import kotlinx.cinterop.interpretCPointer
import kotlinx.cinterop.memScoped
import kotlinx.cinterop.value