Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Shared Preferences - Save, edit, retrieve, delete in Kotlin?
This example demonstrates how Save, edit, retrieve, delete shared preference data in 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_alignParentStart="true" android:layout_centerInParent="true" android:onClick="saveData" android:text="Save" /> <Button android:id="@+id/btnRetrieve" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:layout_centerHorizontal="true" android:onClick="readData" android:text="Read" /> <Button android:id="@+id/btnClear" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentEnd="true" android:layout_centerInParent="true" 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_alignParentEnd="true" 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" /> <LinearLayout android:layout_width="match_parent" android:layout_height="400dp" android:layout_below="@+id/btnSave" android:layout_marginTop="10dp" android:orientation="vertical" android:padding="8dp"> <TextView android:id="@+id/textViewName" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:textColor="@android:color/holo_blue_light" android:textSize="24sp" android:textStyle="bold" /> <TextView android:id="@+id/textViewEmail" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:textColor="@android:color/holo_blue_light" android:textSize="24sp" android:textStyle="bold"> </LinearLayout> </RelativeLayout>
Step 3 − Add the following code to src/MainActivity.kt
import android.content.Context
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
@Suppress("NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS")
class MainActivity : AppCompatActivity() {
var editTextName: EditText? = null
var editTextEmail: EditText? = null
lateinit var textViewName: TextView
lateinit var textViewEmail: TextView
private val myPreference = "myPref"
private val name = "nameKey"
private val email = "emailKey"
var sharedPreferences: SharedPreferences? = null
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)
sharedPreferences = getSharedPreferences(myPreference, Context.MODE_PRIVATE)
if (sharedPreferences!!.contains(name)) {
editTextName?.setText(sharedPreferences!!.getString(name, ""))
}
if (sharedPreferences!!.contains(email)) {
editTextName?.setText(sharedPreferences!!.getString(email, ""))
}
}
fun readData(view: View) {
textViewEmail = findViewById(R.id.textViewEmail)
textViewName = findViewById(R.id.textViewName)
var strName: String = editTextName?.text.toString().trim()
var strEmail: String = editTextEmail?.text.toString().trim()
strName = sharedPreferences!!.getString(name, "")
strEmail = sharedPreferences!!.getString(email, "")
sharedPreferences = getSharedPreferences(myPreference, Context.MODE_PRIVATE)
if (sharedPreferences!!.contains(name)) {
textViewName.text = strName
}
if (sharedPreferences!!.contains(email)) {
textViewEmail.text = strEmail
}
Toast.makeText(baseContext, "Data retrieved", Toast.LENGTH_SHORT).show()
}
fun saveData(view: View) {
val strName: String = editTextName?.text.toString().trim()
val strEmail: String = editTextEmail?.text.toString().trim()
val editor: SharedPreferences.Editor = sharedPreferences!!.edit()
editor.putString(name, strName)
editor.putString(email, strEmail)
editor.apply()
Toast.makeText(baseContext, "Saved", Toast.LENGTH_SHORT).show()
}
fun clearData(view: View) {
editTextName!!.text.clear()
editTextEmail!!.text.clear()
textViewName.text = ""
textViewEmail.text = ""
Toast.makeText(baseContext, "Cleared data", 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="app.com.kotlipapp"> <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 −
Click here to download the project code.
Updated on: 20-Apr-2020
449 Views
Advertisements