ROOM + FLOW CRUD - 1

ROOM을 이용해서 CRUD를 구현해보는 것을 해보겠습니다.

 

기존의 List<DATA> 형태로 가져오는 것이 아니라, Flow<List<Data>> 형태로 가져와서 사용해보겠습니다.

 

일단 기본적인 ROOM 을 만드는 과정입니다.

 

id 'kotlin-kapt'

 

// ROOM
def roomVersion = "2.4.0"

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:1.6.0")

 

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {

        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val db = TextDatabase.getDatabase(this)

        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)

        insertBtn.setOnClickListener {

            CoroutineScope(Dispatchers.IO).launch {
                db.textDao().insert(TextEntity(0, inputArea.text.toString()))
                inputArea.setText("")
            }

        }

        getAllBtn.setOnClickListener {
            CoroutineScope(Dispatchers.IO).launch {
                Log.d("MAINACTIVITY", db.textDao().getAllData().toString())
            }
        }

        deleteBtn.setOnClickListener {
            CoroutineScope(Dispatchers.IO).launch {
                db.textDao().deleteAllData()
            }
        }


    }
}

 

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <EditText
            android:id="@+id/textInputArea"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

        <Button
            android:id="@+id/insert"
            android:text="insert"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <Button
            android:id="@+id/getData"
            android:text="getData"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <Button
            android:id="@+id/delete"
            android:text="delete"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>


    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

 

@Dao
interface TextDao {

    @Query("SELECT * FROM text_table")
    fun getAllData() : List<TextEntity>

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    fun insert(text : TextEntity)

    @Query("DELETE FROM text_table")
    fun deleteAllData()

}

@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
            }
        }

    }

}

@Entity(tableName = "text_table")
data class TextEntity (

    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "id")
    var id : Int,
    @ColumnInfo(name = "text")
    var text : String

)