android - 定期工作请求未在工作管理器中执行 doWork

Question

我正在尝试使用 WorkManager 中的 PeriodicWorkRequest 定期从远程 url 获取数据。我已经实现了逻辑，这里的问题是我没有从 Worker 得到任何响应。

但是它似乎在第一次启动时调用了 doWork()，但是它没有从网络调用中获取数据。令我惊讶的是，当我使用 OneTimeWorkRequest 时，我从 doWork() 和服务器数据中获得了成功结果。

我做错了什么？

代码如下:

worker 类(Class)

public class WorkerClass extends Worker {

private Context context;
public static final String EXTRA_WORKER_CLASS = "extra_tag";

public SpecialOffer(@NonNull Context context, @NonNull WorkerParameters workerParams) {
    super(context, workerParams);
    this.context = context;
}

@NonNull
@Override
public Result doWork() {
    Log.d("WORKER_PERIOD", "started");
    String url = "https://sampleurl/get.php";
    //Volley synchronous call
    RequestFuture<String> future = RequestFuture.newFuture();
    StringRequest request = new StringRequest(url, future, future);
    MySingleton.getInstance(context).addToRequestQueue(request);

    try {
        String response = future.get();
        Data data = new Data.Builder()
                .putString(EXTRA_SPECIAL_CARS, response)
                .build();
        setOutputData(data);
        Log.d("WORKER_RESPONSE", response);
        return Result.SUCCESS;
    } catch (InterruptedException | ExecutionException e) {
        return Result.FAILURE;
    }
}
}

调用任务的方法

public void callTask(){
     PeriodicWorkRequest periodicRequest =
                new PeriodicWorkRequest.Builder(WorkerClass.class, 15, TimeUnit.MINUTES)
                        .setConstraints(constraints)
                        .addTag("SPECIAL_OFFER")
                        .build();

        workManager.enqueueUniquePeriodicWork("SPECIAL_OFFER",
                ExistingPeriodicWorkPolicy.KEEP, periodicRequest);

        workManager.getWorkInfoByIdLiveData(periodicRequest.getId())
                .observe(getActivity(), workInfo -> {
                    Log.d("WORKER_PERIOD", "observed");
                    // Do something with the status
                    if (workInfo != null && workInfo.getState().isFinished()) {
                        Log.d("WORKER_PERIOD", "observed");
                        String ava = workInfo.getOutputData().getString(SpecialOffer.EXTRA_SPECIAL_CARS);
                        if (ava.equals("available")) {
                            showSpecialOffer(true);
                        } else {
                            showSpecialOffer(true);
                        }
                    }
                });
}

Answer 1

根据PeriodicWorkRequest Documentation

The normal lifecycle of a PeriodicWorkRequest is ENQUEUED -> RUNNING -> ENQUEUED. By definition, periodic work cannot terminate in a succeeded or failed state, since it must recur. It can only terminate if explicitly cancelled

所以当你在 .observe 中执行 workInfo.getState().isFinished() 时，它总是返回 false因为.isFinished() method documentation说:

returns true for SUCCEEDED, FAILED, and * CANCELLED states