Java 房间数据库。插入成功，但未找到数据

我有一个简单的房间数据库设置，如下所示：

实体类

@Entity
public class User {
 @PrimaryKey
 public int uid;

 @ColumnInfo(name = "first_name")
 public String firstName;

 @ColumnInfo(name = "last_name")
 public String lastName;

 public User(int uid, String firstName, String lastName){
     this.uid = uid;
     this.firstName = firstName;
     this.lastName = lastName;
 }
}

我的Dao接口：

@Dao
public interface UserDao {

 @Query("SELECT * FROM User")
 Flowable<List<User>> getAlls();

 @Insert
 Completable addData(User modelClass);
}

最后，我的ViewModel：

public class RoomWithRxJavaViewModel extends AndroidViewModel {

 private AppDatabase appDatabase;

 public RoomWithRxJavaViewModel(@NonNull Application application) {
    super(application);
    appDatabase = AppDatabase.getDatabase(application);
 }

 public Flowable<List<User>> getList() {
    return appDatabase.userDao().getAlls().subscribeOn(Schedulers.computation())
            .observeOn(AndroidSchedulers.mainThread());
 }

 public Completable addData(User modelClass) {

     return Completable.fromAction(() -> appDatabase.userDao().addData(modelClass))
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread());
 }

}

正如您从代码中看到的，我首先尝试在数据库中创建一个默认用户

如果插入成功（这是因为我总是输入onsuces函数），我想检查更新的用户表的大小，下面是提示： 无论我使用代码插入用户的频率有多高，大小始终为0

我遗漏了什么吗？

你的刀：

@Insert
Single<Long> insert(User user);

---

运行单元测试时，您是否观察到size=0？@Southstar否，这会有区别吗？是的，测试是事务性的-它们创建测试，完成后删除测试row@Southstar但是我不运行单元测试。我在手机上进行本地测试。

RoomWithRxJavaViewModel viewModel = new RoomWithRxJavaViewModel(this.getApplication());

Disposable disposable = viewModel.addData(new User(2, "btt", "bbb"))
.subscribe(
 () -> { //onSucess
   Toast.makeText(this, "Completed!", Toast.LENGTH_SHORT).show();
   Disposable subscribe = viewModel.getList()
   .subscribe(modelClasses ->
       {
         Toast.makeText(this, "RoomWithRx: " + modelClasses.size(), Toast.LENGTH_LONG).show();
       }, e -> Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_LONG).show());
}, //onError
   throwable -> {
     Toast.makeText(this, "Error!" + throwable.getMessage(), Toast.LENGTH_SHORT).show();
  }
);

@Insert
Single<Long> insert(User user);

public Single<Long> addData2(User user) {
    return appDatabase.userDao().addData(user)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread());
}

Disposable subscribe1 = viewModel.addData2(new User(4, "some", "user"))
 .subscribe(
  id -> { //onSucess },
  throwable -> { //onerror }
);