房间更新不更新数据库

Question

我是 Room 新手，在更新数据库时遇到了一些问题。插入和删除按预期工作，但更新没有。数据库中的数据保持不变。我已经尝试使用 @Query 语句中的整个对象和特定字段进行更新。我做错了什么？

实体：

@Entity(tableName = "Appointments")
public class Appointment {

@PrimaryKey
@NonNull
public int AppointmentID;
public Boolean CheckInStatus;

public Appointment(
        @NonNull int AppointmentID,
        Boolean CheckInStatus
) {

    this.AppointmentID = AppointmentID;
    this.CheckInStatus = CheckInStatus;

}

public void setCheckInStatus(Boolean checkInStatus) {
    CheckInStatus = checkInStatus;
}

@NonNull
public int getAppointmentID() {
    return this.AppointmentID;
}

public Boolean getCheckInStatus() {
    return CheckInStatus;
}

public void setID(@NonNull int AppointmentID) {
    this.AppointmentID = AppointmentID;
}

道：

@Update
void update(Appointment appointment);

@Query("UPDATE Appointments SET CheckInStatus = 1 WHERE AppointmentID = :Id")
void updateCheckIn(int Id);

回购：

public void updateCheckIn(int Id) {
    new AppointmentRepository.updateCheckInAsyncTask(mAppointmentDao, Id);
}

public static class updateCheckInAsyncTask extends AsyncTask<Void, Void, Void> {

    private AppointmentDao mAsyncTaskDao;
    private int mId;

    updateCheckInAsyncTask(AppointmentDao dao, int Id) {

        mAsyncTaskDao = dao;
        mId = Id;
    }

    @Override
    protected Void doInBackground(Void... voids) {
        mAsyncTaskDao.updateCheckIn(mId);
        return null;
    }
}

public void update(Appointment appointment) {
    new AppointmentRepository.updateAsyncTask(mAppointmentDao, appointment);
}

private static class updateAsyncTask extends AsyncTask<Void, Void, Void> {

    private AppointmentDao mAsyncTaskDao;
    private Appointment mAppointment;

    updateAsyncTask(AppointmentDao dao, Appointment appointment) {

        mAsyncTaskDao = dao;
        mAppointment = appointment;
    }

    @Override
    protected Void doInBackground(Void... voids) {
        mAsyncTaskDao.update(mAppointment);
        return null;
    }
}

查看模型：

public void update(Appointment appointment) { mRepository.update(appointment); }

public void updateCheckIn(int Id) { mRepository.updateCheckIn(Id); }

活动：

// Update check in status in table
mAppointmentVM.updateCheckIn(mId);

当我走那条路线时，正确的 id 和更新的对象一样被传递。非常感谢任何帮助。

编辑： 最终答案是：

   public void updateCheckIn(int Id) {
    new AppointmentRepository.updateCheckInAsyncTask(mAppointmentDao, Id).execute();
}

public static class updateCheckInAsyncTask extends AsyncTask<Void, Void, Void> {

    private AppointmentDao mAsyncTaskDao;
    private int mId;

    updateCheckInAsyncTask(AppointmentDao dao, int Id) {

        mAsyncTaskDao = dao;
        mId = Id;
    }

    @Override
    protected Void doInBackground(Void... voids) {
        Appointment entity = mAsyncTaskDao.getAppointmentDetails(mId);
        entity.setCheckInStatus(true);
        mAsyncTaskDao.update(entity);
        return null;
    }
}

Answer 1

你可以这样做：

1. 从DB中获取要更新的项目；
2. 通过使用 setter 方法设置 CheckInStatus 来更新 POJO；
3. 只需使用 @Update(onConflict = OnConflictStrategy.REPLACE) 函数并将更新后的 POJO 传递给它（因为 Id 的匹配项及其 主键，DB 会自动识别这种情况并更新所需对象的所有必填字段）；

---

**例子：**

@Override
protected Void doInBackground(Void... voids) {
    Appointment entity = mAsyncTaskDao.getAppointmentById(mId);
    entity.setCheckInStatus(true);
    mAsyncTaskDao.update(entity);
    return null;
}

---

就是这样 :) 祝你好运。