Change the period of a periodic task in Firebase JobDispatcher?

Question

I was using GCM network manager, but then I heard that Firebase JobDispatcher includes GCM plus other features so I'm trying to use that. I have successfully programmed a periodic task and it works fine, but the problem is that I need the period to change and not be fixed from the beginning.

The reason for that is, I'm using an activity recognition service and I want the next time the JobDispatcher executes the periodic task to be based on the detected current activity. For example if you're walking, the next time the task is triggered is after 30 minutes, while if you're in a car then the period is 5 minutes (mainly because if you're in a car it's more likely that your phone will provide different location values in a short while compared to when you're on foot).

This is the way I program the periodic task, as you can see I'm setting a fixed value, I want to know if the service that is triggered by this task can provide a feedback that'll change the period of the task.

 final Builder builder = jobDispatcher.newJobBuilder()
                .setTag(form.tag.get())
                .setRecurring(form.recurring.get())
                .setLifetime(form.persistent.get() ? Lifetime.FOREVER : Lifetime.UNTIL_NEXT_BOOT)
                .setService(DemoJobService.class)
                .setTrigger(Trigger.executionWindow(
                    form.getWinStartSeconds(), form.getWinEndSeconds()))
                .setReplaceCurrent(form.replaceCurrent.get())
                .setRetryStrategy(jobDispatcher.newRetryStrategy(
                    form.retryStrategy.get(),
                    form.getInitialBackoffSeconds(),
                    form.getMaximumBackoffSeconds()));

            if (form.constrainDeviceCharging.get()) {
                builder.addConstraint(Constraint.DEVICE_CHARGING);
            }
            if (form.constrainOnAnyNetwork.get()) {
                builder.addConstraint(Constraint.ON_ANY_NETWORK);
            }
            if (form.constrainOnUnmeteredNetwork.get()) {
                builder.addConstraint(Constraint.ON_UNMETERED_NETWORK);
            }

Answer 1

To do this you'd need to have your onStartJob in DemoJobService.class cancel itself using your tag that you've saved in SharedPrefs / elsewhere (form.tag.get() in your example):

FirebaseJobDispatcher(GooglePlayDriver(context)).cancel(yourTag)

It can then reschedule the job with the updated parameters. Unfortunately there's currently no way to edit jobs, they must be cancelled and recreated!