[Kotlin] SharedPreferences + Singleton Pattern

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">

    <TextView
        android:id="@+id/tvId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Id : "
        android:textSize="30dp"
        android:layout_marginLeft="30dp"
        android:layout_marginBottom="240dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent" />

    <EditText
        android:id="@+id/etId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="number"
        app:layout_constraintTop_toTopOf="@+id/tvId"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvId" />

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

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="text"
        app:layout_constraintTop_toTopOf="@+id/tvName"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvName"/>

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

    <EditText
        android:id="@+id/etAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="number"
        app:layout_constraintTop_toTopOf="@+id/tvAge"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvAge"/>

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Save"
        android:textSize="18dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="60dp"
        app:layout_constraintTop_toBottomOf="@+id/etAge"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <Button
        android:id="@+id/btnLoad"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Load"
        android:textSize="18dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        app:layout_constraintTop_toBottomOf="@+id/btnSave"
        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.Context
import android.content.SharedPreferences
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    lateinit var sharedPreferences: SharedPreferences
    lateinit var editor: SharedPreferences.Editor

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

        sharedPreferences = getSharedPreferences("SharedPreferencesFile", Context.MODE_PRIVATE)
        editor = sharedPreferences.edit()

        btnSave.setOnClickListener {

            var id: Long = 0
            var name = ""
            var age = 0

            if (etId.text.toString() != "") {
                id = etId.text.toString().toLong()
            }

            if (etName.text.toString() != "") {
                name = etName.text.toString()
            }

            if (etAge.text.toString() != "") {
                age = Integer.parseInt(etAge.text.toString())
            }

            editor.putLong("id", id)
            editor.putString("name", name)
            editor.putInt("age", age)

            editor.apply()      // thread non block (asynchronous)
            //        editor.commit()     // thread block (synchronous)

        }

        btnLoad.setOnClickListener {
            val id = sharedPreferences.getLong("id", 0)
            val name = sharedPreferences.getString("name", "")
            val age = sharedPreferences.getInt("age", 0)

            etId.setText(id.toString())
            etName.setText(name)
            etAge.setText(age.toString())
        }

    }

}

실행 결과

 

 

 

 

 

 

 

 

---

SharedPreferences  +  Singleton Pattern

---

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">

    <TextView
        android:id="@+id/tvId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Id : "
        android:textSize="30dp"
        android:layout_marginLeft="30dp"
        android:layout_marginBottom="240dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent" />

    <EditText
        android:id="@+id/etId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="number"
        app:layout_constraintTop_toTopOf="@+id/tvId"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvId" />

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

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="text"
        app:layout_constraintTop_toTopOf="@+id/tvName"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvName"/>

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

    <EditText
        android:id="@+id/etAge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        android:textStyle="bold"
        android:textAlignment="center"
        android:ems="6"
        android:inputType="number"
        app:layout_constraintTop_toTopOf="@+id/tvAge"
        app:layout_constraintLeft_toRightOf="@+id/tvName"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/tvAge"/>

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Save"
        android:textSize="18dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="60dp"
        app:layout_constraintTop_toBottomOf="@+id/etAge"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <Button
        android:id="@+id/btnLoad"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textAllCaps="false"
        android:text="Load"
        android:textSize="18dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        app:layout_constraintTop_toBottomOf="@+id/btnSave"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml

 

 

 

 

 

 

SharedPreferencesManager.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.content.SharedPreferences

class SharedPreferencesManager {

    companion object {
        private var sp: SharedPreferences? = null
        private var editor: SharedPreferences.Editor? = null

        private fun getInstance(context: Context): SharedPreferences {
            synchronized(this) {
                sp = context.getSharedPreferences("SharedPreferencesFile", Context.MODE_PRIVATE)
                return sp!!
            }
        }

        fun putLong(context: Context, key: String, value: Long) {
            editor = getInstance(context).edit()
            editor!!.putLong(key, value)
            editor!!.apply()
        }

        fun getLong(context: Context, key: String, default: Long): Long {
            return getInstance(context).getLong(key, default)
        }

        fun putString(context: Context, key: String, value: String) {
            editor = getInstance(context).edit()
            editor!!.putString(key, value)
            editor!!.apply()
        }

        fun getString(context: Context, key: String, default: String): String {
            return getInstance(context).getString(key, default)!!
        }

        fun putInt(context: Context, key: String, value: Int) {
            editor = getInstance(context).edit()
            editor!!.putInt(key, value)
            editor!!.apply()
        }

        fun getInt(context: Context, key: String, default: Int): Int {
            return getInstance(context).getInt(key, default)
        }
    }

}

 

 

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

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

        btnSave.setOnClickListener {
            val id: String = etId.text.toString()
            val name: String = etName.text.toString()
            val age: String = etAge.text.toString()

            if (id != "") {
                SharedPreferencesManager.putLong(applicationContext, "id", id.toLong())
            }
            if (name != "") {
                SharedPreferencesManager.putString(applicationContext, "name", etName.text.toString())
            }
            if (age != "") {
                SharedPreferencesManager.putInt(applicationContext, "age", Integer.parseInt(age))
            }
        }

        btnLoad.setOnClickListener {
            val id: Long = SharedPreferencesManager.getLong(applicationContext, "id", 0)
            val name: String = SharedPreferencesManager.getString(applicationContext, "name", "")
            val age: Int = SharedPreferencesManager.getInt(applicationContext, "age", 0)

            etId.setText(id.toString())
            etName.setText(name)
            etAge.setText(age.toString())
        }
    }

}

실행 결과

 

 

 

 

 

 

 

 

 

참고

---

Type mismatch 발생

 

코틀린에서도 editText.setText() 사용하자.

 

 

 

stackoverflow.com/questions/44493908/setting-text-in-edittext-kotlin

Setting text in EditText Kotlin