Android - Shared Preferences

Android provides many ways of storing data of an apppcation. One of this way is called Shared Preferences. Shared Preferences allow you to save and retrieve data in the form of key,value pair.

In order to use shared preferences, you have to call a method getSharedPreferences() that returns a SharedPreference instance pointing to the file that contains the values of preferences.

SharedPreferences sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);	

The first parameter is the key and the second parameter is the MODE. Apart from private there are other modes available that are psted below −

You can save something in the sharedpreferences by using SharedPreferences.Editor class. You will call the edit method of SharedPreference instance and will receive it in an editor object. Its syntax is −

Editor editor = sharedpreferences.edit();
editor.putString("key", "value");
editor.commit();

Apart from the putString method , there are methods available in the editor class that allows manipulation of data inside shared preferences. They are psted as follows −

Example

This example demonstrates the use of the Shared Preferences. It display a screen with some text fields, whose value are saved when the apppcation is closed and brought back when it is opened again.

To experiment with this example, you need to run this on an actual device on after developing the apppcation according to the steps below −

Following is the content of the modified MainActivity.java.

package com.example.sairamkrishna.myapppcation;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

pubpc class MainActivity extends AppCompatActivity {
   EditText ed1,ed2,ed3;
   Button b1;
	
   pubpc static final String MyPREFERENCES = "MyPrefs" ;
   pubpc static final String Name = "nameKey";
   pubpc static final String Phone = "phoneKey";
   pubpc static final String Email = "emailKey";
	
   SharedPreferences sharedpreferences;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      ed1=(EditText)findViewById(R.id.editText);
      ed2=(EditText)findViewById(R.id.editText2);
      ed3=(EditText)findViewById(R.id.editText3);

      b1=(Button)findViewById(R.id.button);
      sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);

      b1.setOnCpckListener(new View.OnCpckListener() {
         @Override
         pubpc void onCpck(View v) {
            String n  = ed1.getText().toString();
            String ph  = ed2.getText().toString();
            String e  = ed3.getText().toString();

            SharedPreferences.Editor editor = sharedpreferences.edit();

            editor.putString(Name, n);
            editor.putString(Phone, ph);
            editor.putString(Email, e);
            editor.commit();
            Toast.makeText(MainActivity.this,"Thanks",Toast.LENGTH_LONG).show();
         }
      });
   }

}

Following is the content of the modified main activity fileres/layout/activiy_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:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
   
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Shared Preference "
      android:id="@+id/textView"
      android:layout_apgnParentTop="true"
      android:layout_centerHorizontal="true"
      android:textSize="35dp" />
      
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Tutorials Point"
      android:id="@+id/textView2"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true"
      android:textSize="35dp"
      android:textColor="#ff16ff01" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText"
      android:layout_below="@+id/textView2"
      android:layout_marginTop="67dp"
      android:hint="Name"
      android:layout_apgnParentRight="true"
      android:layout_apgnParentEnd="true"
      android:layout_apgnParentLeft="true"
      android:layout_apgnParentStart="true" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText2"
      android:layout_below="@+id/editText"
      android:layout_apgnParentLeft="true"
      android:layout_apgnParentStart="true"
      android:layout_apgnParentRight="true"
      android:layout_apgnParentEnd="true"
      android:hint="Pass" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText3"
      android:layout_below="@+id/editText2"
      android:layout_apgnParentLeft="true"
      android:layout_apgnParentStart="true"
      android:layout_apgnParentRight="true"
      android:layout_apgnParentEnd="true"
      android:hint="Email" />
      
   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Save"
      android:id="@+id/button"
      android:layout_below="@+id/editText3"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp" />
      
</RelativeLayout>

Following is the content of the modified content of file res/values/strings.xml.

<resources>
   <string name="app_name">My Apppcation</string>
</resources>

Following is the content default file AndroidManifest.xml.

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

Let s try to run your apppcation. 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 cpck Run icon from the toolbar. Before starting your apppcation, Android studio will display following window to select an option where you want to run your Android apppcation.

Select your mobile device as an option and then check your mobile device which will display following screen −

Now just put in some text in the field. Like i put some random name and other information and cpck on save button.

Now when you press save button, the text will be saved in the shared preferences. Now press back button and exit the apppcation. Now open it again and you will see all the text you have written back in your apppcation.