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An Annotation argument must be a compile time constant

i have seen this question. Similar error.But in my case it is different.

While working with Room i was creating table. it was working fine.

@Daointerface 
UserDao {
@Query("SELECT * FROM user")
fun getAll(): List<User>

@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insert(user: User)

@Delete
fun delete(user: User)}

but then i found all table Names must be stored in a different class. like table name "user" - > Stored in different class.

Eg.

class Table {
companion object {
    const val USER_TABLE = "user"
}}

But below code is not working . it is not picking up table name from Table class. Giving compile time error . "An Annotation argument must be a compile time constant" please help me out.What wrong in it

@Query("SELECT * FROM $Table.USER_TABLE")
fun getAll(): List<User>
like image 951
Tarun Avatar asked Jun 04 '18 10:06

Tarun


2 Answers

You need to escape the String concatenation when using @Value annotation with the dollar symbol in Kotlin (prepend \ to $):

@Query("SELECT * FROM \$Table.USER_TABLE")
fun getAll(): List<User>
like image 160
floatingmuseum Avatar answered Nov 09 '22 18:11

floatingmuseum


The problem is the one stated in the error, you can't have dynamically defined arguments for your @Query annotation. If you want to define the name of the table somewhere else, use string concatenation. You can do it like this:

@Query("SELECT * FROM " + Table.USER_TABLE)
fun getAll(): List<User>

This is how they do it in this google sample.

like image 6
Levi Moreira Avatar answered Nov 09 '22 18:11

Levi Moreira