How to check if a DB exists in Android?

Question

I am using Room API to implement a DB in my Android app. It seems that every time I load my app it tries to create the database again and again. Is there any way to restrict

Answer 1

You can get count of entities in db (TODO app - example). entities > 0.

class App: Application() {
    override fun onCreate() {
        super.onCreate()
        instance = this
        database = Room.databaseBuilder(applicationContext,
            AppDatabase::class.java, "database").build()
    }
    companion object {
        lateinit var instance: App
        lateinit var database: AppDatabase
    }
}

//DB class

 @Database(entities = [Task::class], version = 1, exportSchema = false)
       abstract class AppDatabase : RoomDatabase() {
       abstract fun taskDao(): TaskDao
}

//Dao interface

   @Dao
    interface TaskDao {
        @Query("SELECT COUNT(id) FROM tasks")
        fun getTasksCount(): Int
    }

//Model

@Entity(indices = [Index(value = ["title"], unique = true)], tableName ="tasks")
    class Task(
        var title: String = "",
        var description: String = "",
        var date: Date,
        @Embedded 
        var remind: Constants.RemindPeriod = Constants.RemindPeriod.MIN5,
        @Embedded
        var prior: Priority) : Serializable {
        @PrimaryKey(autoGenerate = true)
        var id: Long = 0}

//CheckDB

 private fun checkDatabaseState() {
        doAsync {
            val db = App.database
            val entityCount = db.taskDao().getTasksCount().or(0)
            isDatabaseNotEmpty = entityCount > 0
        }
    }