[안드로이드/Android/Kotlin] TodoList 만들기 : 2편(MVVM/ROOM/ViewPager2 사용)

2편에서

• Adapter
• Room Database 사용 및 Model
• Repository
• ViewModel

Room Database 사용

TodoDAO.kt

@Dao
interface TodoDAO {
    @Query("SELECT * from Todo where status = 'BEFORE'")
    fun getTodoBeforeList(): LiveData<List<TodoModel>>
    @Insert
    fun insertTodo(todoModel: TodoModel)

    @Query("SELECT * from Todo where status = 'MIDDLE'")
    fun getTodoMiddleList(): LiveData<List<TodoModel>>

    @Query("UPDATE Todo SET status = 'MIDDLE' WHERE status = 'BEFORE' and id = :todoModelID")
    fun updateTodoBeforeToMiddle(todoModelID: Long?)

    @Query("UPDATE Todo SET status = 'AFTER' WHERE status = 'MIDDLE' and id = :todoModelID")
    fun updateTodoMiddleToAfter(todoModelID: Long?)

    @Query("SELECT * from Todo where status = 'AFTER'")
    fun getTodoAfterList(): LiveData<List<TodoModel>>

    //@Query("DELETE FROM Todo where id = :todoModelID")
    @Delete
    fun deleteTodo(todoModel: TodoModel)
}

TodoDatabase.kt

@Database(entities = [TodoModel::class], version = 1)
abstract class TodoDatabase: RoomDatabase() {
    abstract fun todoDao(): TodoDAO

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

        fun getInstance(context: Context): TodoDatabase = INSTANCE ?: synchronized(this) {
            INSTANCE ?: buildDatabase(context).also { INSTANCE = it }
        }

        private fun buildDatabase(context: Context) =
            Room.databaseBuilder(
                context.applicationContext,
                TodoDatabase::class.java, "Todo.db"
            ).build()
    }
}

TodoModel.kt

@Entity(tableName = "Todo")
data class TodoModel (
    @PrimaryKey(autoGenerate = true)
    var id: Long?,
    @ColumnInfo(name = "description")
    var description: String,
    @ColumnInfo(name = "status")
    var status: String
    ) { constructor(): this(null, "","")
}

TodoRepository.kt

class TodoRepository(application: Application) {
    private var mTodoDatabase: TodoDatabase
    private var mTodoDAO: TodoDAO
    private var mTodoItems: LiveData<List<TodoModel>>
    private var mTodoItemsMiddle: LiveData<List<TodoModel>>
    private var mTodoItemsAfter: LiveData<List<TodoModel>>

    init {
        mTodoDatabase = TodoDatabase.getInstance(application)
        mTodoDAO = mTodoDatabase.todoDao()
        mTodoItems = mTodoDAO.getTodoBeforeList()
        mTodoItemsMiddle = mTodoDAO.getTodoMiddleList()
        mTodoItemsAfter = mTodoDAO.getTodoAfterList()
    }

    fun getTodoBeforeList(): LiveData<List<TodoModel>> {
        return mTodoItems
    }

    fun getTodoMiddleList(): LiveData<List<TodoModel>> {
        return mTodoItemsMiddle
    }

    fun getTodoAfterList(): LiveData<List<TodoModel>> {
        return mTodoItemsAfter
    }

    fun insertTodo(todoModel: TodoModel) {
        Thread{
            mTodoDAO.insertTodo(todoModel)
        }.start()
    }

    fun deleteTodo(todoModel: TodoModel) {
        Thread{
            mTodoDAO.deleteTodo(todoModel)
        }.start()
    }

    fun updateTodoBeforeToMiddle(todoModelID: Long?) {
        Thread{
            mTodoDAO.updateTodoBeforeToMiddle(todoModelID)
        }.start()
    }

    fun updateTodoMiddleToAfter(todoModelID: Long?) {
        Thread{
            mTodoDAO.updateTodoMiddleToAfter(todoModelID)
        }.start()
    }

}

TodoViewModel.kt

class TodoViewModel(application: Application) : AndroidViewModel(application) {
    private val mTodoRepository: TodoRepository
    private var mTodoItems: LiveData<List<TodoModel>>
    private var mTodoItemsMiddle: LiveData<List<TodoModel>>
    private var mTodoItemsAfter: LiveData<List<TodoModel>>

    val text = MutableLiveData("")
    val addBtnClickEvent = SingleLiveEvent<Any>()

    init {
        mTodoRepository = TodoRepository(application)
        mTodoItems = mTodoRepository.getTodoBeforeList()
        mTodoItemsMiddle = mTodoRepository.getTodoMiddleList()
        mTodoItemsAfter = mTodoRepository.getTodoAfterList()
    }

    fun insertTodo(todoModel: TodoModel) {
        mTodoRepository.insertTodo(todoModel)
    }

    fun deleteTodo(todoModel: TodoModel) {
        mTodoRepository.deleteTodo(todoModel)
    }

    fun getTodoBeforeList(): LiveData<List<TodoModel>> {
        return mTodoItems
    }

    fun getTodoMiddleList(): LiveData<List<TodoModel>> {
        return mTodoItemsMiddle
    }

    fun getTodoAfterList(): LiveData<List<TodoModel>> {
        return mTodoItemsAfter
    }

    fun updateTodoBeforeToMiddle(todoModelID: Long?) {
        mTodoRepository.updateTodoBeforeToMiddle(todoModelID)
    }

    fun updateTodoMiddleToAfter(todoModelID: Long?) {
        mTodoRepository.updateTodoMiddleToAfter(todoModelID)
    }

    fun onClickAddButton() {
        System.out.println("onClickAddButton")
        addBtnClickEvent.call()
    }

    fun deleteText() {
        text.value = null
    }

}

SingleLiveEvent에 대한 것은 다른 포스팅 참조
https://velog.io/@dustndus8/%EC%95%88%EB%93%9C%EB%A1%9C%EC%9D%B4%EB%93%9CAndroid-MVVM-%EC%9D%B4%EB%B2%A4%ED%8A%B8-%EC%B2%98%EB%A6%AC-ovw9fsa1

ROOM 이용해 TodoList 만들기 참조 출처 : https://doitddo.tistory.com/52