SharedPreferences in Android Provides a way for Storing data into key-value pair. In Order to use Shared – Preferences we have to use getSharedPreference() Method. Shared Preferences in Android is used to store the small data into key and value pair such as User Preference setting, User logged in or not, To store this type of data in Android We can use SharedPreferences
To Access Shared Preference in Android:
SharedPreferences userPref = getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE)
Here, The First Parameter PREF_NAME is key which we will be using to identify this Shared Preference and Second Parameter is the mode. All the modes and it’s description is As follows:
| MODE | Description |
|---|---|
MODE_PRIVATE |
This mode is useful when you want your file to be accessed only by the calling app |
MODE_APPEND |
This method mode will append the new Preference to the existing one |
MODE_WORLD_READABLE |
This mode allow other application to read the preferences |
MODE_WORLD_WRITEABLE |
This mode allow other application to write the preferences |
MODE_MULTI_PROCESS |
This mode will check for modification of preferences even if the Shared Preference instance has already been loaded |
MODE_ENABLE_WRITE_AHEAD_LOGGING |
Database open flag. When it is set, it would enable write ahead logging by default |
Other Methods for Accessing Shared Preference API :
- getSharedPreference(): Used from within your activity to access application Level Preference
- getPreference(): Used from within your activity, to access Activity Specific Preference
- getDefaultSharedPreference(): We should use it to get the shared preferences that Android’s overall preference framework.
Save Data Inside Shared Preferences
To save data inside SharedPreferences, SharedPreferences.Editor class is used. To get an Instance of SharedPreferences.Editor class, We will call edit() method on the Instance of SharedPreferences Syntax is as follows :
SharedPreferences sharedPreferences = getSharedPreferences("userPref",MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean("UserLogin",true);
editor.apply();
There are other methods available in the Editor class that allows manipulation of data inside
SharedPreferences.
| Methods | Description |
|---|---|
apply() |
It will commit all the changes made in editor |
clear() |
It will clear all the values from the editor |
putInt(String key, int value) |
It will save integer value in preference editor |
putFloat(String key, float value) |
It will save float value in preference editor |
putBoolean(String key, boolean value) |
It will save boolean value in preference editor |
putString(String key, String value) |
It will save string value in preference editor |
remove(String key) |
It will remove the value from the editor whose key is passed as parameter |
Example to Demonstrate the use of SharedPreferences in Android :
Here is an example Demonstrating How to use SharedPreferences in A real-life scenario. Here We have created the app that will show Login Screen only for the user who has not logged in yet, if the user is already logged in then we will redirect user to our Home Screen using SharedPreferences.
Here we have created SharedPrefUtil class Which will provide SharedPreferences API, Here we have used SharedPreferences API to save the session whether user logged in or not.
File: SharedPrefUtil Class
Kotlin
Java
Kotlin
package com.vairagicodes.sharedpreferencesloginexample.util
import android.content.Context
import android.content.SharedPreferences
object SharedPrefUtil {
const val USER_PREF = "user_pref"
const val IS_USER_LOGGED_IN = "is_user_logged_in"
fun saveIfUserIsLoggedIn(context: Context, isUserLoggedIn: Boolean) {
val sharedPreferences: SharedPreferences = context.getSharedPreferences(USER_PREF, Context.MODE_PRIVATE)
with(sharedPreferences.edit()) {
putBoolean(IS_USER_LOGGED_IN, isUserLoggedIn)
apply()
}
}
fun isUserLoggedIn(context: Context): Boolean {
val sharedPreferences: SharedPreferences = context.getSharedPreferences(USER_PREF, Context.MODE_PRIVATE)
return sharedPreferences.getBoolean(IS_USER_LOGGED_IN, false)
}
}
Java
package com.vairagicodes.sharedpreferencesloginexample.util;
import android.content.Context;
import android.content.SharedPreferences;
public class SharedPrefUtil {
public static final String USER_PREF = "user_pref";
public static final String IS_USER_LOGGED_IN = "is_user_logged_in";
public static void saveIfUserIsLoggedIn(Context context,
boolean isUserLoggedIn) {
SharedPreferences sharedPreferences =
context.getSharedPreferences(USER_PREF,
Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean(IS_USER_LOGGED_IN, isUserLoggedIn);
editor.apply();
}
public static Boolean isUserLoggedIn(Context context) {
SharedPreferences sharedPreferences =
context.getSharedPreferences(USER_PREF,
Context.MODE_PRIVATE);
return sharedPreferences.getBoolean(IS_USER_LOGGED_IN, false);
}
}
LoginActivity, where we will save whether the user is logged in or not
File : activity_login.xml
XML
XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical"
android:padding="16dp"
tools:context=".LoginActivity">
<EditText
android:id="@+id/user_name_et"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:autofillHints="no"
android:hint="Enter username"
android:inputType="text" />
<EditText
android:id="@+id/email_name_et"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:autofillHints="yes"
android:hint="Enter email"
android:inputType="textEmailAddress" />
<Button
android:id="@+id/login_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:text="Login" />
</LinearLayout>
LoginActivity: Kotlin/Java File
Kotlin
Java
Kotlin
package com.vairagicodes.sharedpreferencesloginexample
import android.content.Intent
import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import com.vairagicodes.sharedpreferencesloginexample.util.SharedPrefUtil
import com.vairagicodes.sharedprefexample.HomeScreenActivity
import com.vairagicodes.sharedprefexample.R
class LoginActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_login)
val loginButton = findViewById<Button>(R.id.login_btn)
loginButton.setOnClickListener {
SharedPrefUtil.saveIfUserIsLoggedIn(this, true)
startActivity(Intent(this, HomeScreenActivity::class.java))
finish()
}
}
}
Java
package com.vairagicodes.sharedpreferencesloginexample;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
import com.vairagicodes.sharedpreferencesloginexample.util.SharedPrefUtil;
public class LoginActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
Button loginBtn = findViewById(R.id.login_btn);
loginBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SharedPrefUtil.saveIfUserIsLoggedIn(LoginActivity.this,true);
startActivity(new Intent(LoginActivity.this,
HomeScreenActivity.class));
finish();
}
});
}
}
File : activity_home_screen.xml
XML
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:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".HomeScreenActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Home Screen"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:textSize="30sp"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
HomeScreenActivity: Java/Kotlin File
Kotlin
Java
Kotlin
package com.vairagicodes.sharedprefexample
import android.os.Bundle
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
class HomeScreenActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_home_screen)
}
}
Java
package com.vairagicodes.sharedpreferencesloginexample;
import android.os.Bundle;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class HomeScreenActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home_screen);
}
}
MainActivity: where we redirect users, If logged in then we will redirect user to LoginActivity otherwise we will redirect it to HomeScreenActivity.
File : activity_main.xml
XML
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:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Splash Screen"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:textSize="30sp"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity: Kotlin/Java File
Kotlin
Java
Kotlin
package com.vairagicodes.sharedpreferencesloginexample
import android.content.Intent
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.vairagicodes.sharedpreferencesloginexample.util.SharedPrefUtil
import com.vairagicodes.sharedprefexample.HomeScreenActivity
import com.vairagicodes.sharedprefexample.R
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val isUserLoggedIn = SharedPrefUtil.isUserLoggedIn(this)
if (isUserLoggedIn) {
startActivity(Intent(this, HomeScreenActivity::class.java))
finish()
} else {
startActivity(Intent(this, LoginActivity::class.java))
finish()
}
}
}
Java
package com.vairagicodes.sharedpreferencesloginexample;
import android.content.Intent;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import com.vairagicodes.sharedpreferencesloginexample.util.SharedPrefUtil;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
boolean isUserLoggedIn = SharedPrefUtil.isUserLoggedIn(this);
if (isUserLoggedIn) {
startActivity(new Intent(MainActivity.this,
HomeScreenActivity.class));
finish();
} else {
startActivity(new Intent(MainActivity.this,
LoginActivity.class));
finish();
}
}
}
Output:
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