Asynchronous Worker in Android WorkManager

Question

Google recently announced new WorkManager architecture component. It makes it easy to schedule synchronous work by implementing doWork() in Worker class, but what if I want to do some asynchronous work in the background? For example, I want to make a network service call using Retrofit. I know I can make a synchronous network request, but it would block the thread and just feels wrong. Is there any solution for this or it is just not supported at the moment?

Answer 1

I used a countdownlatch and waited for this to reach 0, which will only happen once the asynchronous callback has updated it. See this code:

public WorkerResult doWork() {

        final WorkerResult[] result = {WorkerResult.RETRY};
        CountDownLatch countDownLatch = new CountDownLatch(1);
        FirebaseFirestore db = FirebaseFirestore.getInstance();

        db.collection("collection").whereEqualTo("this","that").get().addOnCompleteListener(task -> {
            if(task.isSuccessful()) {
                task.getResult().getDocuments().get(0).getReference().update("field", "value")
                        .addOnCompleteListener(task2 -> {
                            if (task2.isSuccessful()) {
                                result[0] = WorkerResult.SUCCESS;
                            } else {
                                result[0] = WorkerResult.RETRY;
                            }
                            countDownLatch.countDown();
                        });
            } else {
                result[0] = WorkerResult.RETRY;
                countDownLatch.countDown();
            }
        });

        try {
            countDownLatch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        return result[0];

    }