But in Android `FutureTask` can receive a callback...

# coroutines

[dave08]

But in Android FutureTask can receive a callback when it's finished, so you wouldn't have to block an extra thread to wait for the result... and it implements Future from api level 1...

[Jonathan]

So you can write your own suspend await() on it.

[Jonathan]

Yes. But anyway can link the doc of this FutureTask please ?

[Jonathan]

I only found this: https://developer.android.com/reference/java/util/concurrent/FutureTask.html and it is not possible to install any callback on it.

[dave08]

Look at the constructor..

[dave08]

FutureTask(Callable<V> callable)

[Jonathan]

That is what will be executed... this is not a callback.

[Jonathan]

There is no way install a callback on it once the instance exist. And if you want to create a future you could anyway directly use "kotlinx.coroutines" async { doSomethingUseful() }

[dave08]

Ohh, you're right... I was in the middle of something else and didn't notice... the truth is that my use case was in using Koush/Ion http client, but then they have their own future implementation w/ a callback... it's funny that Android doesn't have one.. I guess that's back to AsysncTask 🤒

[dave08]

Which is like async {}

[dave08]

...

[Jonathan]

😉

[dave08]

I guess when the result is not so important to get right away one can do a loop w/ delay and isDone check... to avoid blocking the thread but that's probably overkill

[Jonathan]

Yeah... I think I would rather create an async task which wait on the result and maybe use a dedicated thread pool for it. But the best would be to not have to deal with such future. Only dealing with Deferred and eventually CompletableFuture would be my aim.