我对suspended
在主线程上时协程的内部工作感到好奇。真正的问题是如何在主线程上记录suspended
函数,它是一个协程。究竟在哪里执行死刑?是虚拟线程吗?
答案 0 :(得分:2)
如果您正在谈论记录协程名称:
您可以通过
实现为协程命名(如果需要自定义名称):launch(CoroutineName("My-Coroutine"))
在IntelliJ工具栏菜单中启用日志记录:运行->编辑配置并添加
-Dkotlinx.coroutines.debug
在VM选项中。
然后您可以在logcat中看到@My-Coroutine
。
在修改配置后尝试以下代码:
fun main() = runBlocking {
println(" 'runBlocking': I'm working in thread ${Thread.currentThread().name}")
val job = launch(CoroutineName("my-custom-name")) {
println(" 'runBlocking': I'm working in thread ${Thread.currentThread().name}")
}
job.join()}
答案 1 :(得分:1)
您可以在创建协程时使用CoroutineName(name:String)
方法为协程命名:
repeat(5) {
GlobalScope.launch(CoroutineName("$it")) {
displayGreetingsFor(it)
}
}
要检索为协程命名的名称,请使用coroutineContext[CoroutineName.Key]
,如下所示:
private suspend fun displayGreetingsFor(i: Int) {
delay(100)
println(
" ${coroutineContext[CoroutineName.Key]} is executing on thread : ${Thread.currentThread().name}"
)
}
这将在控制台上按o / p打印:
CoroutineName(0) is executing on thread : DefaultDispatcher-worker-3
CoroutineName(1) is executing on thread : DefaultDispatcher-worker-2
CoroutineName(2) is executing on thread : DefaultDispatcher-worker-8
CoroutineName(3) is executing on thread : DefaultDispatcher-worker-6
CoroutineName(4) is executing on thread : DefaultDispatcher-worker-5
答案 2 :(得分:0)
这是文档中的示例,我想这是您可以获得的最接近的
。import kotlinx.coroutines.*
fun main() = runBlocking<Unit> {
launch { // context of the parent, main runBlocking coroutine
println("main runBlocking : I'm working in thread ${Thread.currentThread().name}")
}
launch(Dispatchers.Unconfined) { // not confined -- will work with main thread
println("Unconfined : I'm working in thread ${Thread.currentThread().name}")
}
launch(Dispatchers.Default) { // will get dispatched to DefaultDispatcher
println("Default : I'm working in thread ${Thread.currentThread().name}")
}
launch(newSingleThreadContext("MyOwnThread")) { // will get its own new thread
println("newSingleThreadContext: I'm working in thread ${Thread.currentThread().name}")
}
}
将打印此内容。
Unconfined : I'm working in thread main
Default : I'm working in thread DefaultDispatcher-worker-1
newSingleThreadContext: I'm working in thread MyOwnThread
main runBlocking : I'm working in thread main
了解更多here
答案 3 :(得分:0)
其他答案没有直接回答问题“ 如何在Kotlin中获得协程的名称?”;相反,他们建议如何命名协程。
如果在协程内部,则可以使用currentCoroutineContext()[CoroutineName]
来检索名称。
如果在协程外部,则没有直接方法使用对Job
或Deferred
的引用来检索名称(太糟糕了)。但是,可以使用反射技巧。当然,附带了通常的警告,即没有类型安全和侵入可能随时更改的内部API。
@Suppress("UNCHECKED_CAST")
val nameString = AbstractCoroutine::class.memberFunctions
.single { it.name == "nameString" } as Function1<AbstractCoroutine<*>, String>
val name = nameString(job as AbstractCoroutine<*>)
.replace("\"", "")
.takeWhile { it != '#' }
包含此代码的方法/函数必须用@InternalCoroutinesApi
标记。