Coroutines必须取消合作社
查看官方文档，似乎只有在取消取消时才能取消Coroutine，这意味着它在执行代码之前检查了它是否有效。 link> link
如果情况是这样，范围是如何的。取消（）取消所有Coroutines取消/停止在该范围内运行？
val startTime = System.currentTimeMillis()
val job = launch(Dispatchers.Default) {
var nextPrintTime = startTime
var i = 0
while (i < 5) { // computation loop, just wastes CPU
// print a message twice a second
if (System.currentTimeMillis() >= nextPrintTime) {
println("job: I'm sleeping ${i++} ...")
nextPrintTime += 500L
}
}
}
delay(1300L) // delay a bit
println("main: I'm tired of waiting!")
job.cancelAndJoin() // cancels the job and waits for its completion
println("main: Now I can quit.")
Looking at the official docs, it seems like a coroutine can only be cancelled if it cooperates with cancellation meaning it checks if it's active before executing its code. LINK
If that's the case, how does scope.cancel() cancels all coroutines cancel/stop running inside that scope?
val startTime = System.currentTimeMillis()
val job = launch(Dispatchers.Default) {
var nextPrintTime = startTime
var i = 0
while (i < 5) { // computation loop, just wastes CPU
// print a message twice a second
if (System.currentTimeMillis() >= nextPrintTime) {
println("job: I'm sleeping ${i++} ...")
nextPrintTime += 500L
}
}
}
delay(1300L) // delay a bit
println("main: I'm tired of waiting!")
job.cancelAndJoin() // cancels the job and waits for its completion
println("main: Now I can quit.")
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它实际上并没有取消工作。在
job.cancelandjoin（）中，代码等到white（i＆lt; 5）已完成，然后才存在。如果阅读链接的文章到末尾，您将找到合作作业的示例，该示例使用
while（isActive）。ISACTIVE返回false在取消作业时。发生这种情况时，while-loop将正常退出。It doesn't actually cancel the job. In the
job.cancelAndJoin()the code waits untilwhile (i < 5)is done and then the job exists.If read the linked article to the end, you'll find the example of a cooperative job, which uses
while (isActive).isActivereturnsfalsewhen the job gets cancelled. When this happens, the while-loop will just quit normally.