I can't reach database inspector to add data-CodePudding

My app builds successfully, but i cannot reach database inspector. Whenever i open database inspector, it does not show me any database. I tried restarting things, but those didn't work. I tried inspector in another app which i download from google courses, it was working there. I'm stuck here, how can i get over this.

Thats what i see when i open database inspector:

Entity

@Entity
data class Note(
    @PrimaryKey(autoGenerate = true)
    val id: Long = 0,
    @ColumnInfo(name = "note_text")
    val noteText: String,
    @ColumnInfo(name = "note_date")
    val noteDate: Date
)

Dao

@Dao
interface NoteDao {

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insert(note: Note)

    @Update
    suspend fun update(note: Note)

    @Delete
    suspend fun delete(note: Note)

    @Query("SELECT * FROM Note WHERE id = :id")
    fun getNote(id: Long): Flow<Note>

    @Query("SELECT * from Note ORDER BY note_date DESC")
    fun getAllNotes(): Flow<List<Note>>
}

RoomDatabase

private const val TAG = "NoteRoomDatabase"

@Database(entities = [Note::class], version = 1, exportSchema = false)
@TypeConverters(Converters::class)
abstract class NoteRoomDatabase: RoomDatabase() {

    abstract fun noteDao(): NoteDao

    companion object {
        @Volatile
        private var INSTANCE: NoteRoomDatabase? = null

        fun getDatabase(context: Context): NoteRoomDatabase {
            return INSTANCE ?: synchronized(this) {
                val instance = Room.databaseBuilder(
                    context.applicationContext,
                    NoteRoomDatabase::class.java,
                    "note_database")
                    .fallbackToDestructiveMigration()
                    .build()

                Log.d(TAG, "Database created!")
                INSTANCE = instance
                return instance
            }
        }

    }
}

Application

class NotesApplication : Application() {

    val database: NoteRoomDatabase by lazy { NoteRoomDatabase.getDatabase(this) }
}

ViewModelFactory

class AppViewModelFactory(private val noteDao: NoteDao) : ViewModelProvider.Factory {
    override fun <T : ViewModel> create(modelClass: Class<T>): T {
        if (modelClass.isAssignableFrom(AppViewModel::class.java)) {
            @Suppress("UNCHECKED_CAST")
            return AppViewModel(noteDao) as T
        }
        throw IllegalArgumentException("Unknown ViewModel class")
    }
}

How i call it from fragments

private val viewModel: AppViewModel by activityViewModels {
    AppViewModelFactory(
        (activity?.application as NotesApplication).database.noteDao()
    )
}

CodePudding user response：

for that you have to create your database first .. when you run your activity this doesn't execute your database classes, so for that in your first main activity

 lifecycleScope.launch(Dispatchers.IO){
                 val database: NoteRoomDatabase by lazy { NoteRoomDatabase.getDatabase(this)
             
               
            }

CodePudding user response：

The reason that you see nothing is because there is nothing until an attempt is made to access the database.

You can force an open of the database by getting a SupportSQLiteDatabase (even if you don't use it)

e.g.

val database: NoteRoomDatabase by lazy { NoteRoomDatabase.getDatabase(this) }
database.openHelper.writableDatabase //<<<<<<<<<< ADDED

You could alternately force an open within the getDatabase function after the build e.g.

instance.openHelper.writableDatabase