如何从 Worker 获取输出数据？ (MVVM + WorkManager + Room)

问题描述 投票：0回答：1

我正在使用 MVVM 并从我的存储库中排队一个工人。工人的工作只是将一些数据插入数据库，但我想在后台任务完成后访问一些输出数据，这样我就可以验证数据是否毫无问题地进入数据库。我尝试使用 WorkInfo.State 或使用 getOutputData 获取数据，但由于某种原因它似乎不起作用。关于如何实现这一目标的任何想法？

这里是参考代码：

AddWorkoutWorker.java

public class AddWorkoutWorker extends Worker {

    public static final String WORK_WORKOUT_NAME = "workout";
    public static final String WORK_WORKOUT_TYPE = "type";
    public static final String WORK_FAILURE_TAG = "failed";
    public static final String WORK_SUCCESS_TAG = "success";
    private static final String WORKER_TAG = "Worker Tag";
    private WorkoutDAO workoutDAO;
    private AppDatabase database;
    Boolean workSuccess;

    //Worker constructor
    public AddWorkoutWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
        database = AppDatabase.getInstance(context);
        workoutDAO = database.workoutDAO();
    }

    @NonNull
    @Override
    public Result doWork() {

        //Gets input data
        Data inputData = getInputData();
        String workoutName = inputData.getString(WORK_WORKOUT_NAME);
        String workoutType = inputData.getString(WORK_WORKOUT_TYPE);


        if (workoutName != null && workoutType != null){
            //Inserts item in database through DAO
            Log.d(WORKER_TAG,"Worker data passed: "+workoutName + workoutType);
            Workout workout = new Workout(workoutName, workoutType);
            workoutDAO.insertSingleWorkout(workout);
        }else{
            //Returns false if the worker doesn't add the item to the database
            workSuccess = false;
            Data output = new Data.Builder()
                    .putBoolean(WORK_FAILURE_TAG,workSuccess)
                    .build();
            return Result.failure(output);
        }

        //Returns true if the worker adds the item to the database
        workSuccess = true;
        Data output = new Data.Builder()
                .putBoolean(WORK_SUCCESS_TAG, workSuccess)
                .build();

        return Result.success(output);
    }
}

AddWorkoutRepository.java

public class AddWorkoutRepository{

    private static final String REPOSITORY_TAG = "REPOSITORY TAG";
    public static final String WORKER_QUEUE_TAG = "Importing Single Workout";
    public WorkoutDAO workoutDAO;
    private final WorkManager workManager;
    private AppDatabase database;
    //private LiveData<List<Workout>> workouts;



    public AddWorkoutRepository(Application application){

        database = AppDatabase.getInstance(application);
        workoutDAO = database.workoutDAO();
        workManager = WorkManager.getInstance(application.getApplicationContext());
        //workouts = workoutDAO.getAllWorkoutsLiveData();

    }

    /*public LiveData<List<Workout>> getAllWorkouts(){
        return workouts;
    }*/

    public void insertWorkout(Workout workout){

        String workoutName = workout.getWorkoutName();
        String workoutType = workout.getWorkoutType();

        Log.d(REPOSITORY_TAG, "Insert Values passed: "+workoutName + workoutType);

        Data data = new Data.Builder()
                .putString(WORK_WORKOUT_NAME, workoutName)
                .putString(WORK_WORKOUT_TYPE, workoutType)
                .build();

        OneTimeWorkRequest importDataRequest = new OneTimeWorkRequest.Builder(AddWorkoutWorker.class)
                .setInputData(data)
                .addTag(WORKER_QUEUE_TAG)
                .build();

        workManager.enqueue(importDataRequest);

        Log.d(REPOSITORY_TAG, "After work manager task OK");

    }

}
java android mvvm android-room android-workmanager
1个回答
1
投票

好的，所以我想通了。我使用 WorkInfo 提供的 LiveData obj 来获取输出数据和任务状态。

  1. 我做的第一件事是在我的 ViewModel 中声明 LiveData obj 
    private LiveData<List<WorkInfo>> workerOutPut;
  2. 然后在视图模型构造函数中像这样初始化我的 LiveData 
    workerOutPut = workManager.getWorkInfosByTagLiveData(ADD_WORKOUT_WORKER_QUEUE_TAG);
  3. 为 LiveData 制作了一个 getter（当然在 ViewModel 中）
  4. 然后我只是简单地在我的活动中创建了一个观察者，它根据我在 Worker 输出数据中设置的布尔值检查 Worker 的状态。

就是这样。我是这一切的新手，所以如果有人要添加任何内容，请随时添加。我会发布完整的代码给其他新“玩家”来帮助他们。

Worker.java

public class AddWorkoutWorker extends Worker {

    public static final String WORK_WORKOUT_NAME = "workout";
    public static final String WORK_WORKOUT_TYPE = "type";
    public static final String WORK_FAILURE_TAG = "failed";
    public static final String WORK_SUCCESS_TAG = "success";
    private static final String ADD_WORKOUT_WORKER_TAG = "Worker Tag";
    private WorkoutDAO workoutDAO;
    private AppDatabase database;
    Boolean workSuccess;

    //Worker constructor
    public AddWorkoutWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
        database = AppDatabase.getInstance(context);
        workoutDAO = database.workoutDAO();
    }

    @NonNull
    @Override
    public Result doWork() {

        //Gets input data
        Data inputData = getInputData();
        String workoutName = inputData.getString(WORK_WORKOUT_NAME);
        String workoutType = inputData.getString(WORK_WORKOUT_TYPE);


        if (workoutName != null && workoutType != null){
            //Inserts item in database through DAO
            Log.d(ADD_WORKOUT_WORKER_TAG,"Worker data passed: "+workoutName + workoutType);
            Workout workout = new Workout(workoutName, workoutType);
            workoutDAO.insertSingleWorkout(workout);
        }else{
            //Returns false if the worker doesn't add the item to the database
            workSuccess = false;
            Data output = new Data.Builder()
                    .putBoolean(WORK_FAILURE_TAG,workSuccess)
                    .build();
            return Result.failure(output);
        }

        //Returns true if the worker adds the item to the database
        workSuccess = true;
        Data output = new Data.Builder()
                .putBoolean(WORK_SUCCESS_TAG, workSuccess)
                .build();

        return Result.success(output);
    }
}

ViewModel.java

public class AddWorkoutViewModel extends AndroidViewModel {

    private static final String WORKOUT_VIEW_MODEL = "Workout View Model";
    private AddWorkoutRepository repository;
    private AddWorkoutWorker worker;
    private WorkManager workManager;
    private Boolean check;
    private LiveData<List<WorkInfo>> workerOutPut;
    //private LiveData<List<Workout>> AllWorkouts;

    public AddWorkoutViewModel(@NonNull Application application) {
        super(application);
        repository = new AddWorkoutRepository(application);
        workManager = WorkManager.getInstance(application);
        workerOutPut = workManager.getWorkInfosByTagLiveData(ADD_WORKOUT_WORKER_QUEUE_TAG);
        //AllWorkouts = repository.getAllWorkouts();
    }


    /*public LiveData<List<Workout>> getWorkoutList(){
        return AllWorkouts;
    }*/

    public LiveData<List<WorkInfo>> checkWorkerStatus(){
        return workerOutPut;
    }

    public void insertData(Workout workout){
        Log.d(WORKOUT_VIEW_MODEL,"View Model Insert Data");
        repository.insertWorkout(workout);
    }
}

活动中的观察者

//Observes LiveData from WorkManager AddWorkoutWorker to validate if worker functioned correctly
        mAddWorkoutViewModel.checkWorkerStatus().observe(this, new Observer<List<WorkInfo>>() {
            @Override
            public void onChanged(List<WorkInfo> workInfos) {

                if(workInfos.isEmpty() || workInfos == null){
                    Log.d(ADD_WORKOUT_WORKER_EMPTY,"Worker is empty");
                }else{

                    if(workInfos.get(0).getOutputData().getBoolean(WORK_SUCCESS_TAG, false)){

                        //If works do stuff here

                    }else{
                        Toast.makeText(AddWorkoutActivity.this,"Something went wrong. Try again.",Toast.LENGTH_LONG);
                    }

                }

            }
        });

对于那些可能想知道的人。我使用 workInfos.get(0) 因为我们只有一个正在检查的工人。我假设如果我们同时有多个工人，我们可以为每个人提出一个案例。

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