如何在不破坏 MVP 模式的情况下使用 Room？

Question

I'm using a Room database in my app and I'm trying to follow the MVP pattern, so I want to use a presenter to call functions that perform database operations. An android application Context is needed to get a database reference so in the View (Activity) I call:

AppDatabase db = Room.databaseBuilder(getApplicationContext(), AppDatabase.class, "AppDatabase").build();

AppDatabase is an abstract class that extends RoomDatabase , has a bunch of android imports and contains a DAO interface. This design is from Android's official guide.

Now, would it break the MVP pattern if I passed and used that AppDatabase object (or the DAO interface since it is the one that actually contains database operations methods) in the presenter? The DAO contains SQL queries and has a bunch of android imports, with methods like dao.insert(item) .

edit:

AppDatabase class and ItemDao interface:

@TypeConverters({Converters.class})
public abstract class AppDatabase extends RoomDatabase {
    public abstract ItemDao itemDao();
}

@Dao
public interface ItemDao {
    @Query("SELECT * FROM item")
    List<Item> getAll();

    @Query("SELECT * FROM item WHERE date BETWEEN :from AND :to")
    List<Item> findItemsBetweenDates(LocalDate from, LocalDate to);

    @Insert
    void insert(Item... items);
}

Answer 1

No you wont be breaking MVP structure as long as dependencies are travelling from the View(Activity or Fragments) to the Presenter. It is a good idea to expose your DAO rather than the app database.

I would also suggest to add the AppDatabase class file to your post to make it more explicit.

EDIT

Instead of exposing DAO, create Repository interface, which abstracts DAO and the repository's implementation itself from the calling element(which could be PRESENTER, CONTROLLER or VIEWMODEL, whatever you prefer). This will make the Repository only dependent on DAO's public API and not on its implementation, make DAO only dependent on the Entities it uses and make Entities a completely free element.