У меня есть объект User, в котором хранится список пользовательских объектов Notifications.Хотя я использовал TypeConverters, я все еще получаю сообщение об ошибке для запроса.
Мой пользовательский объект (пропущен метод получения и установки)
@Entity(tableName = "User")
public class User {
@PrimaryKey(autoGenerate = true)
private int userId;
@ColumnInfo(name = "username")
private String username;
@ColumnInfo(name = "number")
private String number;
@TypeConverters(Converters.class)
private List<Notifications> notifications;
public User(String username, String number, List<Notifications> notifications) {
this.username = username;
this.number = number;
this.notifications = notifications;
}
}
интерфейс userDao
@Dao
public interface UserDao {
@Query("SELECT * FROM User")
List<User> getAll();
@Query("SELECT COUNT(*) from User")
int countUsers();
@Query("SELECT notifications from User where userId LIKE :userId")
List<Notifications> getNotifications(int userId);
@Insert
void insert(User... users);
@Delete
void delete(User... users);
@Update
void update(User... users);
}
Класс конвертера
public class Converters {
@TypeConverter
public static List<Notifications> fromString(String value) {
Type listType = new TypeToken<List<Notifications>>() {}.getType();
List<Notifications> notifications = new Gson().fromJson(value,listType);
return notifications;
}
@TypeConverter
public static String listToString(List<Notifications> list) {
Gson gson = new Gson();
return gson.toJson(list);
}
}
Класс уведомлений (пропущены геттеры и сеттеры)
public class Notifications {
private String app;
private String type;
private String time;
public Notifications(String app, String type, String time) {
this.app = app;
this.type = type;
this.time = time;
}
}
Класс AppDatabase
@Database(entities = {User.class}, version = 1)
@TypeConverters({Converters.class})
public abstract class AppDatabase extends RoomDatabase {
private static AppDatabase INSTANCE;
public abstract UserDao userDao();
public static AppDatabase getAppDatabase(Context context) {
if (INSTANCE == null) {
INSTANCE =
Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, "user-database")
.allowMainThreadQueries()
.build();
}
return INSTANCE;
}
public static void destroyInstance() {
INSTANCE = null;
}
}
Я получаю ошибку
error: Not sure how to convert a Cursor to this method's return type
и
The query returns some columns [notifications] which are not use by com.example.ark.example.database.Notifications. You can use @ColumnInfo annotation on the fields to specify the mapping. com.example.ark.example.database.Notifications has some fields [app, type, time] which are not returned by the query. If they are not supposed to be read from the result, you can mark them with @Ignore annotation. You can suppress this warning by annotating the method with @SuppressWarnings(RoomWarnings.CURSOR_MISMATCH). Columns returned by the query: notifications. Fields in com.example.ark.example.database.Notifications: app, type, time.
Не уверен, что я ошибаюсь, поскольку преобразователи типов выглядят хорошо для меня.