当 onStopped 结束时，如何在我的 CoroutineWorker 中执行清理代码？

Question

我升级到 WorkManager 2.1.0 并尝试使用一些 Kotlin 扩展，包括 CoroutineWorker。我的工作人员之前扩展了 androidx.work.Worker，它正在通过覆盖 onStopped 来执行清理代码。为什么 onStopped 在 CoroutineWorker 中是最终的？在 CoroutineWorker 停止后，我还有其他方法可以执行清理代码吗？

根据 this blog post，这应该是一项功能吗？

Answer 1

您始终可以使用 job.invokeOnCompletetion，而不必依赖 CoroutineWorker 的 onStopped 回调。例如

import android.content.Context
import android.util.Log
import androidx.work.CoroutineWorker
import androidx.work.WorkerParameters
import kotlinx.coroutines.CancellationException
import kotlinx.coroutines.async
import kotlinx.coroutines.coroutineScope

class TestWorker(context: Context, params: WorkerParameters) : CoroutineWorker(context, params) {

    companion object {
        private const val TAG = "TestWorker"
    }

    override suspend fun doWork(): Result {
        return coroutineScope {
            val job = async {
                someWork()
            }

            job.invokeOnCompletion { exception: Throwable? ->
                when(exception) {
                    is CancellationException -> {
                        Log.e(TAG, "Cleanup on completion", exception)
                        // cleanup on cancellations
                    }
                    else -> {
                        // do something else.
                    }
                }
            }

            job.await()
        }
    }

    suspend fun someWork(): Result {
        TODO()
    }
}

Answer 2

来自 Kotlin 文档：

Cancellable suspending functions throw CancellationException on cancellation which can be handled in the usual way. For example, try {...} finally {...} expression and Kotlin use function execute their finalization actions normally when a coroutine is cancelled. Coroutines documentation

这意味着您可以用通常的方式清理协程代码，Java/Kotlin 方法是 try 和 finally：

    override suspend fun doWork(): Result {
        return try {
            work()
            Result.success()
        } catch (e: Exception) {
            Result.failure()
        } finally {
            cleanup()
        }
    }

请注意，您不能在 catch 和 finally 中暂停。如果这样做，请使用 withContext(NonCancellable) NonCancellable documentation

Answer 3

赶上CancellationException

override suspend fun doWork(): Result {
    return try {
        // here do work
        return Result.success()
    } catch (e: CancellationException) {
        // here clean up
        return Result.failure()
    }
}

当 onStopped 结束时，如何在我的 CoroutineWorker 中执行清理代码？

How can I execute cleanup code in my CoroutineWorker when onStopped is final?

android-workmanager