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 this?
db = Room.databaseBuilder(context, AppDatabase.class, "database-name").build();
You are using db that is, in fact, a file. You can check, if it exists, this method could be helpful:
private static boolean doesDatabaseExist(Context context, String dbName) {
File dbFile = context.getDatabasePath(dbName);
return dbFile.exists();
}
When you create database, the database onCreate() callback get called when the application starts. you can use the below code in app activity and that activity call in manifest file in application class call like used below code .
public class AppActivity extends Application {
AppDatabase db;
@Override
public void onCreate() {
super.onCreate();
db = Room.databaseBuilder(getApplicationContext(), AppDatabase.class, "database-name").build();
}
public AppDatabase getDatabase() {
return db;
}
}
and add below line manifest file .. add below line in application tag
android:name="AppActivity"
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
}
}
Try this
if (!db.exists()) {
// Database does not exist so copy it from assets here
Log.i("Database", "Not Found");
} else {
Log.i("Database", "Found");
}
