android-room

问题 I'm developping an Android library, and want to use the new Android Room persistence library inside it. However, when launching I got this error : Caused by: java.lang.RuntimeException: cannot find implementation for MyLibraryName.Database.QSDatabase. QSDatabase_Impl does not exist at android.arch.persistence.room.Room.getGeneratedImplementation(Room.java:90) which means that the annotationProcessor is not generating the extra code during compilation. Btw, everything is working fine when I

问题 I m using Room to query a table from my local Android sqlite database. I've created an abstract class Dao , and wondering if i can pass the name of columns as parameters in method like this : @Query(value = "SELECT :columnName " + " from " + Constant.TABLE_NAME ) public abstract Maybe<List<SomeEntity>> getResults(String columnName); 回答1: No, sorry, that is not supported. Room only supports what SQLite does, and SQLite does not support parameters for column names, table names, etc. 回答2: Can be

问题 I try to implement Room Persistent Database library in android kotlin project, but catch this warning at compile time. I don't know how to solve this warring. warning: There are multiple good constructors and Room will pick the no-arg constructor. You can use the @Ignore annotation to eliminate unwanted constructors. Auto Generated Class public final class Gender { ^ Kotlin Data Class import android.arch.persistence.room.Entity import android.arch.persistence.room.PrimaryKey @Entity data

问题 Consider I have 3 classes User, Address, Location class Address { public String street; public String state; public String city; @ColumnInfo(name = "post_code") public int postCode; @Embedded(prefix = "home_") public Location homeLocation; @Embedded(prefix = "office_") public Location officeLocation; } class Location{ public long lat; public long lng; } @Entity class User { @PrimaryKey public int id; public String firstName; @Embedded(prefix = "addr_") public Address address; } How should i

问题 According the entity-relationship model, the relationship between tbl_post and tbl_category could be specified using Room Persistency Library as follows: @Entity(foreignKeys = @ForeignKey( entity = TblPost.class, parentColumns = "id", childColumns = "tbl_post_id") ) class TblPostCategory { @PrimaryKey public String id; @ColumnInfo(name = "user_id") public String postId; } However TblPostCategory depends on two foreign keys: post_id and category_id from TblPost and TbCategory . How the

问题 According the entity-relationship model, the relationship between tbl_post and tbl_category could be specified using Room Persistency Library as follows: @Entity(foreignKeys = @ForeignKey( entity = TblPost.class, parentColumns = "id", childColumns = "tbl_post_id") ) class TblPostCategory { @PrimaryKey public String id; @ColumnInfo(name = "user_id") public String postId; } However TblPostCategory depends on two foreign keys: post_id and category_id from TblPost and TbCategory . How the

问题 I just implemented Room for offline data saving. But in an Entity class, I am getting the following error: Error:(27, 30) error: Cannot figure out how to save this field into database. You can consider adding a type converter for it. And the class is as following: @Entity(tableName = "firstPageData") public class MainActivityData { @PrimaryKey private String userId; @ColumnInfo(name = "item1_id") private String itemOneId; @ColumnInfo(name = "item2_id") private String itemTwoId; // THIS IS

问题 I just implemented Room for offline data saving. But in an Entity class, I am getting the following error: Error:(27, 30) error: Cannot figure out how to save this field into database. You can consider adding a type converter for it. And the class is as following: @Entity(tableName = "firstPageData") public class MainActivityData { @PrimaryKey private String userId; @ColumnInfo(name = "item1_id") private String itemOneId; @ColumnInfo(name = "item2_id") private String itemTwoId; // THIS IS

问题 I just implemented Room for offline data saving. But in an Entity class, I am getting the following error: Error:(27, 30) error: Cannot figure out how to save this field into database. You can consider adding a type converter for it. And the class is as following: @Entity(tableName = "firstPageData") public class MainActivityData { @PrimaryKey private String userId; @ColumnInfo(name = "item1_id") private String itemOneId; @ColumnInfo(name = "item2_id") private String itemTwoId; // THIS IS

问题 I want to create a database to store what user have searched, I already have this one : @Entity(tableName = "user_searched") data class UserSearched ( @PrimaryKey @NonNull @ColumnInfo(name = "item") val item: String ) And then I want to link to it the response, it could be a single item or a list of : @Entity(tableName = "my_item") data class MyItem( @PrimaryKey @NonNull @ColumnInfo(name = "id") val id: Int, @ColumnInfo(name = "name") val name: String, @ColumnInfo(name = "description") val