QQ: I have a Java API with a callback and I want to wrap that in a kotlin suspend function, so I can...

# coroutines

[enighma]

QQ: I have a Java API with a callback and I want to wrap that in a kotlin suspend function, so I can avoid callback hell

What is the most idiomatic way to do that?

One obvious solution is a Countdown latch, but I imagine there being something more elegant.

[octylFractal]

usually suspendCancellableCoroutine will handle most of the work for you

[octylFractal]

e.g.

suspendCancellableCoroutine { cont ->
  javaApi.withCallback { data, err ->
    if (err != null) cont.resumeWithException(err)
    else cont.resumeWith(data)
  }
}

[ephemient]

or callbackFlow if the callback can be invoked multiple times

[octylFractal]

if you can unsubscribe/cancel on the javaApi (say it returns an Unsubscribe object or something), it's a good idea to also do cont.invokeOnCancellation { unsusbcribe() }

[enighma]

awesome! this was exactly what I was looking for! #solved!

[enighma]

This actually is more what I wanted to do:

AmbientIndication provides @Composable { MyIndication },

That way I can easily either have NoIndication or something else 🙂