kotlin execute code upon coroutine return

Question

Newbie question with coroutines :-)

With coroutines that doesn't return a value, is there a way to execute some code upon the completion of that coroutine ?

In this example, funcA() performs some async call and upon completion funcB, funcC needs to complete, the rest of the code can continue to execute independent of funcA() completion

... other code executing
... other code executing

launch {
  funcA()
}
funcB()
funcC()

... other code executing
... other code executing

One approach would be to enclose funcB, funcC within a method and we can use async with await ... but why return a value just for that.

i.e.

executeFunBC()
{
  funcB()
  funcC()
}


launch {
 val result = funcA()
}
 executeFunBC(result).await()

Basically, in some languages you can use 'blocks' or closures and execute some code upon completion of that block in the same method. (similar to callbacks)

Back to my question:

Is there a way to define the execution of funcB, funcC upon the completion of funcA() in the same function ?

Enselic · Accepted Answer · 2019-10-16 05:21:33Z

2

It's very simple, just do this:

launch {
  funcA()

  // Will not execute until funcA() returns
  funcB() 
  funcC()
}

but make sure you use a dispatcher that works for funcB() and funcC(), e.g. like this launch(Dispatchers.Main) {.

answered Oct 16, 2019 at 5:21

Enselic

5,0222 gold badges32 silver badges43 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

kotlin execute code upon coroutine return

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related