How to use SharedPreferences on Android to store, read and edit values using Kotlin?

https://www.tutorialspoint.com/how-to-use-sharedpreferences-on-android-to-store-read-and-edit-values-using-kotlin

10-09-2020
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Question

How to use SharedPreferences on Android to store, read and edit values using Kotlin?

Kotlin Apps/Applications Mobile Development

This example demonstrates how to use SharedPreferences on Android to store, read and edit values using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="8dp"
   tools:context=".MainActivity">
   <Button
      android:id="@+id/btnSave"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@+id/etEmail"
      android:layout_alignParentStart="true"
      android:layout_marginTop="20dp"
      android:onClick="saveData"
      android:text="Save" />
   <Button
      android:id="@+id/btnRetrieve"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@+id/etEmail"
      android:layout_centerInParent="true"
      android:layout_marginTop="20dp"
      android:onClick="readData"
      android:text="Read" />
   <Button
      android:id="@+id/btnClear"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@+id/etEmail"
      android:layout_alignParentEnd="true"
      android:layout_marginTop="20dp"
      android:onClick="clearData"
      android:text="Clear" />
   <EditText
      android:id="@+id/etEmail"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@+id/etName"
      android:layout_marginTop="10dp"
      android:ems="10"
      android:hint="Email"
      android:inputType="textEmailAddress" />
   <EditText
      android:id="@+id/etName"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_alignStart="@+id/etEmail"
      android:layout_marginTop="40dp"
      android:ems="10"
      android:hint="Name"
      android:inputType="text" />
   <TextView
      android:id="@+id/textViewName"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@+id/btnClear"
      android:layout_marginTop="20dp"
      android:paddingStart="8dp"
      android:textColor="@android:color/background_dark"
      android:textSize="24sp"
      android:textStyle="bold" />
   <TextView
      android:id="@+id/textViewEmail"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@+id/textViewName"
      android:layout_marginTop="10dp"
      android:paddingStart="8dp"
      android:textColor="@android:color/background_dark"
      android:textSize="24sp"
      android:textStyle="bold" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.content.SharedPreferences
import android.os.Bundle
import android.view.View
import android.widget.EditText
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var editTextName: EditText
   private lateinit var editTextEmail: EditText
   lateinit var textViewName: TextView
   lateinit var textViewEmail: TextView
   private val myPreference = "myPref"
   private val name = "nameKey"
   private val email = "emailKey"
   private lateinit var sharedPreferences: SharedPreferences
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      editTextEmail = findViewById(R.id.etEmail)
      editTextName = findViewById(R.id.etName)
      textViewName = findViewById(R.id.textViewName)
      textViewEmail = findViewById(R.id.textViewEmail)
      sharedPreferences = getSharedPreferences(
      myPreference,
      MODE_PRIVATE
      )
      if (sharedPreferences.contains(name)) {
         editTextName.setText(sharedPreferences.getString(name, ""))
      }
      if (sharedPreferences.contains(email)) {
         editTextEmail.setText(sharedPreferences.getString(email, ""))
      }
   }
   fun saveData(view: View) {
      val strName = editTextName.text.toString()
      val strEmail = editTextEmail.text.toString()
      val editor: SharedPreferences.Editor = sharedPreferences.edit()
      editor.putString(name, strName)
      editor.putString(email, strEmail)
      editor.apply()
      Toast.makeText(applicationContext, "Saved", Toast.LENGTH_SHORT).show()
   }
   fun readData(view: View) {
      sharedPreferences = getSharedPreferences(myPreference, MODE_PRIVATE)
      if (sharedPreferences.contains(name)) {
         editTextName.setText(sharedPreferences.getString(name, ""))
         textViewName.text = sharedPreferences.getString(name, "")
      }
      if (sharedPreferences.contains(email)) {
         editTextEmail.setText(sharedPreferences.getString(email, ""))
         textViewEmail.text = sharedPreferences.getString(email, "")
      }
      Toast.makeText(applicationContext, "Retrieved", Toast.LENGTH_SHORT).show()
   }
   fun clearData(view: View) {
      editTextName = findViewById(R.id.etName)
      editTextEmail = findViewById(R.id.etEmail)
      editTextName.setText("")
      editTextEmail.setText("")
      Toast.makeText(
      applicationContext, "Cleared",
      Toast.LENGTH_SHORT
      ).show()
   }
}

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.

Azhar

Published on 09-Sep-2020 12:12:59

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