[Kotlin] MVVM + Coroutine

MVVM  +  Coroutine

---

build.gradle (Module: app)

apply plugin: 'kotlin-kapt'

dependencies {
    // RecyclerView
    implementation 'androidx.recyclerview:recyclerview:1.1.0'
    
    // CardView
    implementation 'androidx.cardview:cardview:1.0.0'
    
    // Room
    implementation 'androidx.room:room-runtime:2.2.5'
    kapt 'androidx.room:room-compiler:2.2.5'
    testImplementation 'androidx.room:room-testing:2.2.5'
    
    // Coroutine
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.7'
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.4'
}

 

 

 

 

 

 

 

UserEntity.kt

package com.jwsoft.kotlinproject

import androidx.room.ColumnInfo
import androidx.room.Entity
import androidx.room.PrimaryKey

@Entity(tableName = "user")
data class UserEntity (

    @PrimaryKey(autoGenerate = true) @ColumnInfo(name = "id") var id: Long?,
    @ColumnInfo(name = "name") var name: String,
    @ColumnInfo(name = "phone") var phone: String,
    @ColumnInfo(name = "age") var age: Int

) {
    constructor() : this(null, "", "", 0)
}

 

 

 

 

 

 

 

UserDao.kt

package com.jwsoft.kotlinproject

import androidx.lifecycle.LiveData
import androidx.room.*

@Dao
interface UserDao {

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    fun insert(user: UserEntity)

    @Query("SELECT * FROM user ORDER BY age ASC")
    fun getAll(): LiveData<List<UserEntity>>

    @Query("DELETE FROM user")
    fun deleteAll()

    @Delete
    fun delete(user: UserEntity)

}

 

 

 

 

 

 

 

UserDB.kt

package com.jwsoft.kotlinproject

import android.content.Context
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase

@Database(entities = [UserEntity::class], version = 1)
abstract class UserDB : RoomDatabase() {
    abstract fun userDao(): UserDao

    companion object {
        private var INSTANCE: UserDB? = null

        fun getInstance(context: Context): UserDB {
            synchronized(this) {
                if (INSTANCE == null) {
                    INSTANCE = Room.databaseBuilder(context, UserDB::class.java, "MyApp.db")
                        .fallbackToDestructiveMigration()
                        .build()
                }
            }
            return INSTANCE!!
        }
    }

}

 

 

 

 

 

 

 

UserRepository.kt

package com.jwsoft.kotlinproject

import android.content.Context
import androidx.lifecycle.LiveData
import kotlinx.coroutines.*
import java.lang.Exception

class UserRepository(context: Context) {

    private var userDB: UserDB = UserDB.getInstance(context)
    private var userDao: UserDao = userDB.userDao()
    private val getAll: LiveData<List<UserEntity>> = userDao.getAll()

    suspend fun insert(user: UserEntity) {
        try {
            withContext(Dispatchers.IO) {
                userDao.insert(user)
            }
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    fun getAll(): LiveData<List<UserEntity>> {
        return getAll
    }

    suspend fun delete(user: UserEntity) {
        try {
            withContext(Dispatchers.IO) {
                userDao.delete(user)
            }
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    suspend fun deleteAll() {
        try {
            withContext(Dispatchers.IO) {
                userDao.deleteAll()
            }
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

}

 

 

 

 

 

 

 

 

UserViewModel.kt

package com.jwsoft.kotlinproject

import android.app.Application
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.LiveData
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch

class UserViewModel(application: Application) : AndroidViewModel(application) {

    private var userRepository: UserRepository = UserRepository(application)
    private val getAll: LiveData<List<UserEntity>> = userRepository.getAll()

    private val viewModelJob = Job()
    private val viewModelScope = CoroutineScope(Dispatchers.Main + viewModelJob)

    fun insert(user: UserEntity) {
        viewModelScope.launch {
            userRepository.insert(user)
        }
    }

    fun getAll(): LiveData<List<UserEntity>> {
        return getAll
    }

    fun delete(user: UserEntity) {
        viewModelScope.launch {
            userRepository.delete(user)
        }
    }

    fun deleteAll() {
        viewModelScope.launch {
            userRepository.deleteAll()
        }
    }

}

 

 

 

 

 

 

 

 

cardview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:layout_margin="10dp"
    android:elevation="10dp"
    app:cardCornerRadius="10dp">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#CCCCCC"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent" />

        <TextView
            android:id="@+id/tvAge"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:textSize="36dp"
            android:hint="30"
            android:textStyle="bold"
            android:gravity="center"
            android:background="#BBBBBB"
            android:layout_marginLeft="10dp"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintBottom_toBottomOf="parent" />

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:gravity="center"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toRightOf="@+id/tvAge">

            <TextView
                android:id="@+id/tvName"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="James Kim"
                android:textAlignment="center"
                android:textSize="30dp"
                android:textStyle="bold" />

            <TextView
                android:id="@+id/tvPhone"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="010-1234-5678"
                android:textSize="18dp"
                android:textStyle="italic"
                android:textAlignment="center"
                android:layout_marginTop="10dp" />

        </LinearLayout>

    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.cardview.widget.CardView>

cardview_item.xml

 

 

 

 

 

 

MyAdapter.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

class MyAdapter(clickInterface: ClickInterface,
                longClickInterface: LongClickInterface)
    : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

    var users: List<UserEntity> = listOf()

    interface ClickInterface {
        fun onClick(position: Int, user: UserEntity)
    }

    interface LongClickInterface {
        fun onLongClick(position: Int, user: UserEntity)
    }

    var clickListener = clickInterface
    var longClickListener = longClickInterface

    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val tvName: TextView = itemView.findViewById(R.id.tvName)
        val tvPhone: TextView = itemView.findViewById(R.id.tvPhone)
        val tvAge: TextView = itemView.findViewById(R.id.tvAge)

        fun bind(position: Int) {
            tvName.text = users[position].name
            tvPhone.text = users[position].phone
            tvAge.text = users[position].age.toString()

            itemView.setOnClickListener {
                clickListener.onClick(position, users[position])
            }
            itemView.setOnLongClickListener {
                longClickListener.onLongClick(position, users[position])
                true
            }
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val context = parent.context
        val inflater: LayoutInflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        val view = inflater.inflate(R.layout.cardview_item, parent, false)

        return MyViewHolder(view)
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.bind(position)
    }

    override fun getItemCount(): Int {
        return users.size
    }

    fun setAdapter(users: List<UserEntity>) {
        this.users = users
        notifyDataSetChanged()
    }

}

 

 

 

 

 

 

 

 

activity_main.xml

<?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">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvUser"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        tools:listitem="@layout/cardview_item"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/btnAdd" />

    <Button
        android:id="@+id/btnAdd"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Add"
        android:textSize="24dp"
        android:textStyle="bold"
        android:layout_margin="4dp"
        app:layout_constraintTop_toBottomOf="@+id/rvUser"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import android.content.DialogInterface
import android.content.Intent
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    private lateinit var viewModel: UserViewModel
    private lateinit var adapter: MyAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var clickInterface = object: MyAdapter.ClickInterface {
            override fun onClick(position: Int, user: UserEntity) {
                var intent = Intent(this@MainActivity, AddActivity::class.java)
                intent.putExtra("id", user.id)
                intent.putExtra("name", user.name)
                intent.putExtra("phone", user.phone)
                intent.putExtra("age", user.age)
                startActivity(intent)
                finish()
            }
        }

        var longClickInterface = object: MyAdapter.LongClickInterface {
            override fun onLongClick(position: Int, user: UserEntity) {
                showAlert(user)
            }
        }

        adapter = MyAdapter(clickInterface, longClickInterface)
        rvUser.adapter = adapter
        rvUser.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)
        rvUser.setHasFixedSize(true)

        viewModel = ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory(application)).get(UserViewModel::class.java)
        viewModel.getAll().observe(this, Observer {
            adapter.setAdapter(it)
        })

        btnAdd.setOnClickListener {
            startActivity(Intent(applicationContext, AddActivity::class.java))
            finish()
        }

    }

    fun showAlert(user: UserEntity) {
        var alertDialog = AlertDialog.Builder(this)
            .setTitle("Delete")
            .setMessage("Do you want to delete user?")
            .setPositiveButton("OK", object: DialogInterface.OnClickListener {
                override fun onClick(dialog: DialogInterface?, which: Int) {
                    viewModel.delete(user)
                }
            })
            .setNegativeButton("Cancel", object: DialogInterface.OnClickListener {
                override fun onClick(dialog: DialogInterface?, which: Int) {
                    Toast.makeText(applicationContext, "Cancel", Toast.LENGTH_SHORT).show()
                }
            })
            .create()

        alertDialog.show()
    }

}

 

 

 

 

 

 

 

 

activity_add.xml

<?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=".AddActivity">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:text="Name : "
        android:textSize="30dp"
        android:layout_marginBottom="100dp"
        app:layout_constraintBottom_toTopOf="@+id/btnDone"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/etName"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="8"
        android:hint="이름"
        android:textAlignment="center"
        android:textSize="30dp"
        android:inputType="text"
        app:layout_constraintBottom_toBottomOf="@+id/tvName"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="@+id/tvName" />

    <TextView
        android:id="@+id/tvPhone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:text="Phone : "
        android:textSize="30dp"
        android:layout_marginTop="40dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/etPhone"
        app:layout_constraintTop_toBottomOf="@+id/tvName" />

    <EditText
        android:id="@+id/etPhone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="8"
        android:hint="번호"
        android:textAlignment="center"
        android:textSize="30dp"
        android:inputType="phone"
        app:layout_constraintBottom_toBottomOf="@+id/tvPhone"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="@+id/tvPhone" />

    <TextView
        android:id="@+id/tvAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:text="Age : "
        android:textSize="30dp"
        android:layout_marginTop="40dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/etAge"
        app:layout_constraintTop_toBottomOf="@+id/tvPhone" />

    <EditText
        android:id="@+id/etAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="8"
        android:hint="나이"
        android:textAlignment="center"
        android:textSize="30dp"
        android:inputType="number"
        app:layout_constraintBottom_toBottomOf="@+id/tvAge"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="@+id/tvAge" />

    <Button
        android:id="@+id/btnDone"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Done"
        android:textSize="24dp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_add.xml

 

 

 

 

 

 

AddActivity.kt

package com.jwsoft.kotlinproject

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.lifecycle.ViewModelProvider
import kotlinx.android.synthetic.main.activity_add.*

class AddActivity : AppCompatActivity() {

    lateinit var viewModel: UserViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_add)

        viewModel = ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory(application)).get(UserViewModel::class.java)

        if (intent.getLongExtra("id", 0) > 0) {
            etName.setText(intent.getStringExtra("name"))
            etPhone.setText(intent.getStringExtra("phone"))
            etAge.setText(intent.getIntExtra("age", 0).toString())
        }

        btnDone.setOnClickListener {
            if (etName.text.toString() != "" && etPhone.text.toString() != "" && etAge.text.toString() != "") {
                var user = UserEntity()
                user.name = etName.text.toString()
                user.phone = etPhone.text.toString()
                user.age = Integer.parseInt(etAge.text.toString())

                if (intent.getLongExtra("id", 0) > 0) {
                    user.id = intent.getLongExtra("id", 0)
                }

                viewModel.insert(user)

                startActivity(Intent(this, MainActivity::class.java))
                finish()
            } else {
                Toast.makeText(applicationContext, "정보를 입력하세요.", Toast.LENGTH_SHORT).show()
            }
        }

    }
}

실행 결과