[Kotlin] MVVM

MVVM  +  Room  +  RecyclerView  +  CardView  +  AlertDialog

---

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'
}

 

 

 

 

 

 

 

 

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) 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.app.Application
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 {
        var INSTANCE: UserDB? = null

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

}

 

 

 

 

 

 

 

 

UserRepository.kt

package com.jwsoft.kotlinproject

import android.app.Application
import androidx.lifecycle.LiveData

class UserRepository(application: Application) {

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

    fun insert(userEntity: UserEntity) {
        try {
            Thread {
                userDao.insert(userEntity)
            }.start()
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

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

    fun deleteAll() {
        try {
            Thread {
                userDao.deleteAll()
            }.start()
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    fun delete(userEntity: UserEntity) {
        try {
            Thread {
                userDao.delete(userEntity)
            }.start()
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

}

 

 

 

 

 

 

 

 

UserViewModel.kt

package com.jwsoft.kotlinproject

import android.app.Application
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.LiveData

class UserViewModel(application: Application) : AndroidViewModel(application) {
    val userRepository: UserRepository = UserRepository(application)
    var getAll: LiveData<List<UserEntity>> = userRepository.getAll()

    fun insert(userEntity: UserEntity) {
        userRepository.insert(userEntity)
    }

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

    fun deleteAll() {
        userRepository.deleteAll()
    }

    fun delete(userEntity: UserEntity) {
        userRepository.delete(userEntity)
    }

}

 

 

 

 

 

 

 

 

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="5dp">

    <androidx.constraintlayout.widget.ConstraintLayout
        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="match_parent">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#CCCCCC"/>

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

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

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

        </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(clickListener: OnItemClickListener,
                longClickListener: OnItemLongClickListener
) : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

    var users: List<UserEntity> = listOf()

    interface OnItemClickListener {
        fun onClick(user: UserEntity)
    }

    interface OnItemLongClickListener {
        fun onLongClick(user: UserEntity)
    }

    var clickListener: OnItemClickListener = clickListener
    var longClickListener: OnItemLongClickListener = longClickListener

    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        lateinit var tvName: TextView
        lateinit var tvPhone: TextView
        lateinit var tvAge: TextView

        fun bind(user: UserEntity) {
            tvName = itemView.findViewById(R.id.tvName)
            tvPhone = itemView.findViewById(R.id.tvPhone)
            tvAge = itemView.findViewById(R.id.tvAge)
            tvName.text = user.name
            tvPhone.text = user.phone
            tvAge.text = user.age.toString()

            itemView.setOnClickListener {
                clickListener.onClick(user)
            }

            itemView.setOnLongClickListener {
                longClickListener.onLongClick(user)
                true
            }
        }
    }

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

        return MyViewHolder(view)
    }

    override fun getItemCount(): Int {
        if (users == null || users.isEmpty()) {
            return 0
        }
        return users.size
    }

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

    fun setAdapter(user: List<UserEntity>) {
        this.users = user
        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="100dp"
        android:textAllCaps="false"
        android:text="Add"
        android:textSize="30dp"
        android:textStyle="bold"
        android:layout_margin="4dp"
        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 androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
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() {

    lateinit var userViewModel: UserViewModel
    lateinit var adapter: MyAdapter

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

        val clickListener = object: MyAdapter.OnItemClickListener {
            override fun onClick(user: UserEntity) {
                var intent: 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()
            }
        }

        val longClickListener = object: MyAdapter.OnItemLongClickListener {
            override fun onLongClick(user: UserEntity) {
                showAlertDialog(user)
            }
        }

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

        userViewModel = ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory(application)).get(UserViewModel::class.java)
        userViewModel.getAll().observe(this, object: Observer<List<UserEntity>> {
            override fun onChanged(t: List<UserEntity>?) {
                if (t != null) {
                    adapter.setAdapter(t)
                }
            }
        })

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

    }

    fun showAlertDialog(user: UserEntity) {
        var alertDialog: 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) {
                    userViewModel.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=".MainActivity">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name"
        android:textSize="24dp"
        android:layout_marginLeft="20dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/btnDone"
        app:layout_constraintLeft_toLeftOf="parent" />

    <TextView
        android:id="@+id/tvPhone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Phone"
        android:textSize="24dp"
        android:layout_marginTop="30dp"
        app:layout_constraintLeft_toLeftOf="@+id/tvName"
        app:layout_constraintTop_toBottomOf="@+id/tvName"/>

    <TextView
        android:id="@+id/tvAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Age"
        android:textSize="24dp"
        android:layout_marginTop="30dp"
        app:layout_constraintLeft_toLeftOf="@+id/tvName"
        app:layout_constraintTop_toBottomOf="@+id/tvPhone"/>

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="12"
        android:layout_marginLeft="30dp"
        app:layout_constraintStart_toEndOf="@+id/tvName"
        app:layout_constraintTop_toTopOf="@+id/tvName"
        app:layout_constraintBottom_toBottomOf="@+id/tvName" />

    <EditText
        android:id="@+id/etPhone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="12"
        android:inputType="phone"
        app:layout_constraintTop_toTopOf="@+id/tvPhone"
        app:layout_constraintBottom_toBottomOf="@+id/tvPhone"
        app:layout_constraintStart_toStartOf="@+id/etName" />

    <EditText
        android:id="@+id/etAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="12"
        app:layout_constraintTop_toTopOf="@+id/tvAge"
        app:layout_constraintBottom_toBottomOf="@+id/tvAge"
        app:layout_constraintStart_toStartOf="@+id/etPhone" />

    <Button
        android:id="@+id/btnDone"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:textAllCaps="false"
        android:text="Done"
        android:textSize="26dp"
        android:textStyle="bold"
        android:layout_margin="4dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="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 androidx.lifecycle.ViewModelProvider
import kotlinx.android.synthetic.main.activity_add.*

class AddActivity : AppCompatActivity() {

    lateinit var userViewModel: UserViewModel

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

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

        etName.setText(intent.getStringExtra("name"))
        etPhone.setText(intent.getStringExtra("phone"))
        etAge.setText(intent.getIntExtra("age", 0).toString())

        btnDone.setOnClickListener {

            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)
            }

            userViewModel.insert(user)

            startActivity(Intent(this, MainActivity::class.java))
            finish()
        }

    }
}

실행 결과