How to call a function after delay in Kotlin?

Question

As the title, is there any way to call a function after delay (1 second for example) in Kotlin?

Answer 1

I recommended using SingleThread because you do not have to kill it after using. Also, "stop()" method is deprecated in Kotlin language.

private fun mDoThisJob(){

    Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate({
        //TODO: You can write your periodical job here..!

    }, 1, 1, TimeUnit.SECONDS)
}

Moreover, you can use it for periodical job. It is very useful. If you would like to do job for each second, you can set because parameters of it:

Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit);

TimeUnit values are: NANOSECONDS, MICROSECONDS, MILLISECONDS, SECONDS, MINUTES, HOURS, DAYS.

@canerkaseler

Answer 2

If you're using more recent Android APIs the Handler empty constructor has been deprecated and you should include a Looper. You can easily get one through Looper.getMainLooper().

    Handler(Looper.getMainLooper()).postDelayed({
        //Your code
    }, 2000) //millis

Answer 3

You have to import the following two libraries:

import java.util.*
import kotlin.concurrent.schedule

and after that use it in this way:

Timer().schedule(10000){
    //do something
}

Answer 4

If you are looking for generic usage, here is my suggestion:

Create a class named as Run:

class Run {
    companion object {
        fun after(delay: Long, process: () -> Unit) {
            Handler().postDelayed({
                process()
            }, delay)
        }
    }
}

And use like this:

Run.after(1000, {
    // print something useful etc.
})

Answer 5

If you are in a fragment with viewModel scope you can use Kotlin coroutines:

    myViewModel.viewModelScope.launch {
        delay(2000)
        // DoSomething()
    }

Answer 6

You could launch a coroutine, delay it and then call the function:

 /*GlobalScope.*/launch {
   delay(1000)
   yourFn()
 }

If you are outside of a class or object prepend GlobalScope to let the coroutine run there, otherwise it is recommended to implement the CoroutineScope in the surrounding class, which allows to cancel all coroutines associated to that scope if necessary.