Showing detailed progress for running WorkManager workers

问题

I want to replace the job scheduling aspect of my existing data syncing system with the new JetPack WorkManager (link to codelabs) component (in a sandbox branch of the app). My existing system works well but some of the new features in WorkManager would come in handy (e.g. chaining).

My current system uses a shared LiveData to communicate the progress from a job in progress to any UI element (RecyclerView in my case) observing on it (I'm actually SwitchMapping in the ViewModel into a list of SyncItems)

data class SyncItem(
        val title: String,
        private var _progress: Int,
        var total: Int) : BaseObservable() {

    var progress: Int
        @Bindable get() = _progress
        set(value) {
            _progress = value
            notifyPropertyChanged(BR.progress)
        }
}

The new WorkManager component has several methods (getStatusById, getStatusesByTag, etc.) that can be used to retrieve a LiveData with one or more WorkStatuses, but these only report a course-grained status (running, success, failed, cancelled).

What is the recommended way of communicating progress (e.g. '546/1234 items downloaded') to the UI? The setOutputData/getOutputData pair seems to be used more to communicate between Workers (which I need when chaining) than with the UI.

Attached is a screenshot of what it looks like (in a [test] version of my app using my old method) when a user opens the sync status page (2 items completed, rest in progress).

In the final product the user will be able to cancel any jobs in progress and re-issue once-off work requests. Normally the jobs will be fired off by PeriodicWorkRequest.

回答1:

The best way to do it is to write intermediate progress to your own data store and expose a LiveData<>. We are considering adding this feature in a future alpha.

回答2:

Progress report is now available natively. For now just on alpha release.

implementation 'androidx.work:work-runtime:2.3.0-alpha01'

Report progress on Worker:

public class FooWorker extends Worker {

    public FooWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
    }

    @NonNull
    @Override
    public Result doWork() {
        try {
            setProgressAsync(new Data.Builder().putInt("progress", 0).build());
            Thread.sleep(1000);
            setProgressAsync(new Data.Builder().putInt("progress", 50).build());
            Thread.sleep(1000);
            setProgressAsync(new Data.Builder().putInt("progress", 100).build());

            return Result.success();
        } catch (InterruptedException e) {
            e.printStackTrace();
            return Result.failure();
        }
    }
}

Observe progress from Worker:

public class FooActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_foo);

        OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(FooWorker.class)
                .build();

        WorkManager.getInstance(this).beginUniqueWork(
                "test", ExistingWorkPolicy.REPLACE, request).enqueue();

        WorkManager.getInstance(this).getWorkInfosForUniqueWorkLiveData("test").observe(this, new Observer<List<WorkInfo>>() {
            @Override
            public void onChanged(List<WorkInfo> workInfos) {
                if (workInfos.size() > 0) {
                    WorkInfo info = workInfos.get(0);
                    int progress = info.getProgress().getInt("progress", -1);
                    //Do something with progress variable
                }

            }
        });

    }

}

ListenableWorkers can now set progress via the setProgressAsync() API. Also added a corresponding suspend-ing setProgress API in CoroutineWorker and a setProgress in RxWorker which returns a Single. With these new APIs Workers can convey progress information via WorkInfo which has a corresponding getProgress API. (b/79481554)

See WorkManager Version 2.3.0-alpha01

来源：https://stackoverflow.com/questions/50542223/showing-detailed-progress-for-running-workmanager-workers