在文件、数据绑定、Room DB 中发现重复 class

Question

我遇到了一个非常烦人的错误。我正在实施房间数据库。当我在 DAO 中为另一个 table 编写插入查询时，class android 工作室生成与 android 数据绑定相关的编译错误这是我的 DAO Class

@Dao
public interface MyCustomDAO {

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertShop(ShopModel shop);

    //whenever i write this insert query, my android studio generate the stated error
   // and when i remove it project buil successfully

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertAbout(AboutEntity about);

    @Query("Select * From shops")
    LiveData<List<ShopModel>> getShopsData();

}

这是我的关于实体 Class

@Entity(
    tableName = "about",
    foreignKeys = {@ForeignKey(entity = ShopModel.class,parentColumns = "shop_id",childColumns = "id")}
    )
// i have implemented the shopModel class with a col namely, shop_id
public class AboutEntity {

@NonNull
@ColumnInfo(name = "id")
private String shopId;
@ColumnInfo
private String monToFriTiming;
@ColumnInfo
private String satTiming;
@ColumnInfo
private String sunTiming;
@ColumnInfo
private String description;

public AboutEntity(@NonNull String shopId, String monToFriTiming, String satTiming, String sunTiming, String description) {
    this.shopId = shopId;
    this.monToFriTiming = monToFriTiming;
    this.satTiming = satTiming;
    this.sunTiming = sunTiming;
    this.description = description;
}

@NonNull
public String getShopId() {
    return shopId;
}
// other fields getter Methods

}

这是 ShopModel class

@Entity
public class ShopModel {
@NonNull
@PrimaryKey
@ColumnInfo(name = "shop_id")
private String id;

 // some other fields and their implementation in the constructor and getter methods for them

public ShopModel(@NonNull String id) {
    this.id = id;
}

@NonNull
public String getId() {
    return id;
}

} build failed log

Answer 1

如果没有看到您遇到的实际错误，很难说清楚，但我猜您的问题是由于同一 DAO 中的不同实体有多种插入方法。

而不是这样做：

@Dao
public interface WrongDAO {
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertShop(ShopModel shop);

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertAbout(AboutEntity about);

    @Query("Select * From shops")
    LiveData<List<ShopModel>> getShopsData();
}

一般来说，您应该始终为每个实体创建不同的 DAO 以使您的代码更有条理：

@Dao
public interface ShopDAO {
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertShop(ShopModel shop);

    @Query("Select * From shops")
    LiveData<List<ShopModel>> getShopsData();
}

@Dao
public interface AboutDAO {
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertAbout(AboutEntity about);
}

我不确定这在 Room 中是否是强制性的，但到目前为止我看到的所有示例每个实体都有一个 DAO，所以我可能会坚持这一点。

来自official documentation：

It is recommended to have multiple Dao classes in your codebase depending on the tables they touch.

为了使其正常工作，请记住将所有 DAO 包含在 Room 数据库的声明中！

在文件、数据绑定、Room DB 中发现重复 class

Duplicate class found in file, Data Binding, Room DB

android

database

android-room

android-databinding