如何从Android中的Worker类访问Rooms数据库的存储库？

debugcn 发表于 Dev

伊恩·贝尔

我Worker在应用程序中有一个类，希望从Rooms数据库中获取数据。由于我使用的是MVVM体系结构，如何使用Worker类中的存储库从数据库中获取数据？

代码 -

工人阶级

public class SendNotification extends Worker {


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

    @RequiresApi(api = Build.VERSION_CODES.M)
    @NonNull
    @Override
    public Result doWork() {

        String flightnumber = getInputData().getString("flight");
        String date = getInputData().getString("date");
       

        sendNotification(flightnumber,date);

        return Result.success();

    }}

资料库

public class FlightRepository {

    private FlightDao flightDao;
    private LiveData<List<Flight>> allFlights;

    public FlightRepository(Application application) {
        FlightDatabase database = FlightDatabase.getInstance(application);
        flightDao = database.flightDao();
        allFlights = flightDao.getAllFlights();

    }

    public void insert(Flight flight) {
        new InsertFlightAsyncTask(flightDao).execute(flight);
    }

    public void update(Flight flight) {
        new UpdateFlightAsyncTask(flightDao).execute(flight);
    }

    public void delete(Flight flight) {
        new DeleteFlightAsyncTask(flightDao).execute(flight);
    }

    public void deleteAllFlights() {
        new DeleteAllFlightsAsyncTask(flightDao).execute();
    }

    public LiveData<List<Flight>> getAllFlights() {
        return allFlights;
    }

    public Flight getFlight(String flightNumber, String date){
        return flightDao.getFlight(flightNumber,date);
    }

    public boolean existsFlight(String flightNumber, String date){
        return flightDao.existsFlight(flightNumber, date);

}

达里尔·贝利斯（Darryl Bayliss）

你应该能够创建的实例FlightRepository里面Worker：

public class SendNotification extends Worker {

  private FlightRepository flightRepo;


public SendNotification(@NonNull Context context, @NonNull WorkerParameters workerParams) {
    super(context, workerParams);
    this.flightRepo = new FlightRepository(context)
}

@RequiresApi(api = Build.VERSION_CODES.M)
@NonNull
@Override
public Result doWork() {

    String flightnumber = getInputData().getString("flight");
    String date = getInputData().getString("date");
   
    // Do what is needed with flightRepo

    sendNotification(flightnumber,date);

    return Result.success();

}}

在这里做一些假设。我愿意FlightDatabase接受Context而不是Application。我不确定为什么数据库需要访问Application

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