kotlin - 协程作用域被取消后，还可以再次使用吗？

Question

当我们有了协程作用域，当它被取消后，还能再使用吗？
例如对于以下内容，当我有 scope.cancel 时, scope.launch不再工作

    @Test
    fun testingLaunch() {
        val scope = MainScope()
        runBlocking {
            scope.cancel()
            scope.launch {
                try {
                    println("Start Launch 2")
                    delay(200)
                    println("End Launch 2")
                } catch (e: CancellationException) {
                    println("Cancellation Exception")
                }
            }.join()

            println("Finished")
        }
    }

同样，当我们有 scope.cancel之前 await叫，

    @Test
    fun testingAsync() {
        val scope = MainScope()
        runBlocking {
            scope.cancel()
            val defer = scope.async {
                try {
                    println("Start Launch 2")
                    delay(200)
                    println("End Launch 2")
                } catch (e: CancellationException) {
                    println("Cancellation Exception")
                }
            }
            defer.await()
            println("Finished")
        }
    }

它不会执行。相反，它会崩溃

kotlinx.coroutines.JobCancellationException: Job was cancelled
; job=SupervisorJobImpl{Cancelled}@39529185
    at kotlinx.coroutines.JobSupport.cancel(JobSupport.kt:1579)
    at kotlinx.coroutines.CoroutineScopeKt.cancel(CoroutineScope.kt:217)
    at kotlinx.coroutines.CoroutineScopeKt.cancel$default(CoroutineScope.kt:215)
    at com.example.coroutinerevise.CoroutineExperiment$testingAsync$1.invokeSuspend(CoroutineExperiment.kt:241)
    at |b|b|b(Coroutine boundary.|b(|b)
    at kotlinx.coroutines.DeferredCoroutine.await$suspendImpl(Builders.common.kt:101)
    at com.example.coroutinerevise.CoroutineExperiment$testingAsync$1.invokeSuspend(CoroutineExperiment.kt:254)
Caused by: kotlinx.coroutines.JobCancellationException: Job was cancelled; job=SupervisorJobImpl{Cancelled}@39529185
    at kotlinx.coroutines.JobSupport.cancel(JobSupport.kt:1579)
    at kotlinx.coroutines.CoroutineScopeKt.cancel(CoroutineScope.kt:217)
    at kotlinx.coroutines.CoroutineScopeKt.cancel$default(CoroutineScope.kt:215)
    at com.example.coroutinerevise.CoroutineExperiment$testingAsync$1.invokeSuspend(CoroutineExperiment.kt:241)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)

是否真的，取消的协程作用域不能用于 launch或 async了？

Answer 1

而不是使用 CoroutineScope要取消其中的所有已启 Action 业，您可能需要使用基础 CoroutineContext与它的 cancelChildren()不影响Job的方法状态(对于普通的 cancel() 方法不是这样)并允许在调用后继续启动新的协程。