At some point, you'll face a situation where you need to halt a coroutine that's already underway. Let's explore the process of doing so.

Terminating a Job

A job has several functions at its disposal, including cancel, which appears to be the ideal solution. Moreover, we can utilize join to wait until the job has completed its termination.

The example below demonstrates a job being terminated:

runBlocking {
  val job = launch(Dispatchers.Default) {
    for (i in 0..1000) {
      delay(50)
      println("$i..")
    }
    println("Job is completed")
  }
  delay(500)
  println("Terminating")
  job.cancel()
  job.join()
  println("Terminated and done")
}

The output will be:

0..
1..
2..
3..
4..
5..
6..
7..
8..
Terminating
Terminated and done

For more information on canceling Kotlin coroutines like a pro, check out this article: 5 Essential Techniques.