Data always changes dynamically and so we have to keep it updated and show the latest result to users. For this reason, we need to observe the data. LiveData is a lifecycle library class that can observe the data and react.

Let's wrap the getAllUsers() function of UserDao.kt with the LiveData:

@Query("SELECT * FROM USERS")
fun getAllUsers():  LiveData<List<Users>>

The @Query("SELECT * FROM USERS") is to get all the information from the USERS table

So here is the full code of the DAO interface:

@Dao
interface UserDAO {

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    fun addNewUser(users: Users)

    @Query("DELETE FROM USERS")
    fun deleteAllUsers()

    @Query("SELECT * FROM USERS")
    fun getAllUsers():  LiveData<List<Users>>
}

In the MainActivity, we will see how to create an Observer of the data and override the observer's onChanged() function.