ROOM + Coroutine Flow - 4 (Why Room & Coroutine - 2)

Flow를 이용해서 데이터 변화를 감지해보겠습니다.

 

 

id 'kotlin-kapt'

// ROOM
def roomVersion = "2.5.0"

implementation("androidx.room:room-runtime:$roomVersion")
annotationProcessor("androidx.room:room-compiler:$roomVersion")

// To use Kotlin annotation processing tool (kapt)
kapt("androidx.room:room-compiler:$roomVersion")

// Coroutine
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.4")

// Coroutine + Room
implementation("androidx.room:room-ktx:$roomVersion")

 

	class MainActivity : AppCompatActivity() {
	private lateinit var viewModel: MainViewModel
	override fun onCreate(savedInstanceState: Bundle?) {
	super.onCreate(savedInstanceState)
	setContentView(R.layout.activity_main)
	viewModel = ViewModelProvider(this).get(MainViewModel::class.java)
	val inputArea = findViewById<EditText>(R.id.textInputArea)
	val insertBtn = findViewById<Button>(R.id.insert)
	val getAllBtn = findViewById<Button>(R.id.getData)
	val deleteBtn = findViewById<Button>(R.id.delete)
	val resultArea = findViewById<TextView>(R.id.resultArea)
	val db = TextDatabase.getDatabase(this)
	insertBtn.setOnClickListener {
	CoroutineScope(Dispatchers.IO).launch {
	db.textDao().insert(TextEntity(0, inputArea.text.toString()))
	inputArea.setText("")
	}
	}
	getAllBtn.setOnClickListener {
	CoroutineScope(Dispatchers.IO).launch {
	// val resultText = db.textDao().getAllDataNorMal().toString()
	//
	// withContext(Dispatchers.Main) {
	// resultArea.text = resultText
	// }
	viewModel.readData().collect {
	val resultText = it.toString()
	withContext(Dispatchers.Main) {
	resultArea.text = resultText
	}
	}
	}
	}
	deleteBtn.setOnClickListener {
	CoroutineScope(Dispatchers.IO).launch {
	db.textDao().deleteAllData()
	}
	}
	}
	}

view raw MainActivity.kt hosted with ❤ by GitHub

	class MainViewModel(application: Application) : AndroidViewModel(application) {
	val context = getApplication<Application>().applicationContext
	val db = TextDatabase.getDatabase(context)
	fun readData() : Flow<List<TextEntity>> = db.textDao().getAllDataFlow()
	}

view raw MainViewModel.kt hosted with ❤ by GitHub

	@Dao
	interface TextDao {
	@Query("SELECT * FROM text_table")
	fun getAllDataNorMal() : List<TextEntity>
	@Query("SELECT * FROM text_table")
	fun getAllDataFlow() : Flow<List<TextEntity>>
	@Insert(onConflict = OnConflictStrategy.IGNORE)
	fun insert(text : TextEntity)
	@Query("DELETE FROM text_table")
	fun deleteAllData()
	}

view raw TextDao.kt hosted with ❤ by GitHub

	@Database(entities = [TextEntity::class], version = 1)
	abstract class TextDatabase : RoomDatabase() {
	abstract fun textDao() : TextDao
	companion object {
	@Volatile
	private var INSTANCE : TextDatabase? = null
	fun getDatabase(
	context : Context
	) : TextDatabase {
	return INSTANCE ?: synchronized(this){
	val instance = Room.databaseBuilder(
	context.applicationContext,
	TextDatabase::class.java,
	"text_database"
	)
	.fallbackToDestructiveMigration()
	.build()
	INSTANCE = instance
	instance
	}
	}
	}
	}

view raw TextDatabase.kt hosted with ❤ by GitHub

	@Entity(tableName = "text_table")
	data class TextEntity (
	@PrimaryKey(autoGenerate = true)
	@ColumnInfo(name = "id")
	var id : Int,
	@ColumnInfo(name = "text")
	var text : String
	)

view raw TextEntity.kt hosted with ❤ by GitHub