android-room

问题 I am getting the above problem, and am unable to solve even while looking at other similar questions and their solutions, as well as the sqlite document on foreign keys. I understand that a foreign key must exist in the parent table first before it can be created in the child table. However, even though that was done first the problem is still there. This is how my program flows until the point where it crashes: MainActivity -> Create Trip -> Shows up as a RecyclerView -> Click on it to enter

问题 Why does this not work in Room?: val dataSourceFactory = database.gameDao.getGames("Game.platforms LIKE '%XONE%'") @Query("SELECT * FROM Game WHERE :likeClause") fun getGames(likeClause: String): DataSource.Factory<Int, Game> But this does?: @Query("SELECT * FROM Game WHERE Game.platforms LIKE '%XONE%'") fun getGames(): DataSource.Factory<Int, Game> Is there any way to pass in a string that can stand in as part of the query? EDIT: I know this isn't the correct way to form a single LIKE clause

问题 Why does this not work in Room?: val dataSourceFactory = database.gameDao.getGames("Game.platforms LIKE '%XONE%'") @Query("SELECT * FROM Game WHERE :likeClause") fun getGames(likeClause: String): DataSource.Factory<Int, Game> But this does?: @Query("SELECT * FROM Game WHERE Game.platforms LIKE '%XONE%'") fun getGames(): DataSource.Factory<Int, Game> Is there any way to pass in a string that can stand in as part of the query? EDIT: I know this isn't the correct way to form a single LIKE clause

问题 In my activity i have an Observer that observes this query @Query("""Select *, (Select account_id from accounts where account_id = from_account_id) as contact_account_id, (Select first_name from accounts where account_id = from_account_id) as contact_first_name, (Select last_name from accounts where account_id = from_account_id) as contact_last_name from messages inner join messageQueue on messages.client_message_id = messagequeue.client_message_id where ((msg_type = 1 and body <> "") or msg

问题 In my activity i have an Observer that observes this query @Query("""Select *, (Select account_id from accounts where account_id = from_account_id) as contact_account_id, (Select first_name from accounts where account_id = from_account_id) as contact_first_name, (Select last_name from accounts where account_id = from_account_id) as contact_last_name from messages inner join messageQueue on messages.client_message_id = messagequeue.client_message_id where ((msg_type = 1 and body <> "") or msg

问题 In my activity i have an Observer that observes this query @Query("""Select *, (Select account_id from accounts where account_id = from_account_id) as contact_account_id, (Select first_name from accounts where account_id = from_account_id) as contact_first_name, (Select last_name from accounts where account_id = from_account_id) as contact_last_name from messages inner join messageQueue on messages.client_message_id = messagequeue.client_message_id where ((msg_type = 1 and body <> "") or msg

问题 every time i run my app it shows this error in the title and i have searched for the problem some said make the ViewModel constructor public and mine is public other said Either: Remove the Context context and LifecycleOwner lifecycleOwner constructor parameters from your HomeViewModel, or Create a ViewModelProvider.Factory that can build your HomeViewModel instances, and use that factory with ViewModelProviders.of() and i have made the two solutions and still get the same error MainActivity

问题 every time i run my app it shows this error in the title and i have searched for the problem some said make the ViewModel constructor public and mine is public other said Either: Remove the Context context and LifecycleOwner lifecycleOwner constructor parameters from your HomeViewModel, or Create a ViewModelProvider.Factory that can build your HomeViewModel instances, and use that factory with ViewModelProviders.of() and i have made the two solutions and still get the same error MainActivity

问题 I have a Room database using Dao to process queries etc. I am using static (non live data) function to retrieve results via the query, all works well when I manual hard code the Order By values and column as below, however when passing params to the Dao to do the sorting, the Order By reverts back to default (order by id column) and does not retrieve results based on the passed sort param Hard coded Dao example works, results sorted by ASC or DESC @Query("SELECT * FROM cameras WHERE suburb

问题 I try to use a Window Functions in a Room Query. The parser is complaining about my query. I simply try to add a "ROW_NUMBER() OVER (ORDER BY column)" expression in my select statement. Without this expression, the query is running correctly. Parser error: extraneous input '(' expecting {<EOF>, ';', ',', K_ALTER, K_ANALYZE, K_ATTACH, K_BEGIN, K_COMMIT, K_CREATE, K_DELETE, K_DETACH, K_DROP, K_END, K_EXCEPT, K_EXPLAIN, K_FROM, K_GROUP, K_INSERT, K_INTERSECT, K_LIMIT, K_ORDER, K_PRAGMA, K