Mange User Session using Shared Preference-II with example

In our  previous post we seen "The Shared Preferences and it uses And how you can use it in our android apps".In this post we are creating simple login form and manage session of a user using Shared Preference.

 
1. Create a new project in Eclipse IDE File --> New --> Android Application Project and fill all the required details
2. I am adding alert dialog manager class to show alert messages while validating the login form. Create a new class and name it as AlertManager.java and paste the following code.

AlertManager.java

/**
     * Function to display simple Alert Dialog
     * @param context - application context
     * @param title - alert dialog title
     * @param message - alert message
     * @param status - success/failure (used to set icon)
     *               - pass null if you don't want icon
     * */
package com.androidgreeve.sessions;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
 
public class AlertManager {
  
    public void showAlertDialog(Context context, String title, String message,
            Boolean status) {
        AlertDialog alertDialog = new AlertDialog.Builder(context).create();
 
        // Setting Dialog Title
        alertDialog.setTitle(title);
 
        // Setting Dialog Message
        alertDialog.setMessage(message);
 
        if(status != null)
            // Setting alert dialog icon
            alertDialog.setIcon((status) ? R.drawable.success : R.drawable.fail);
 
        // Setting OK Button
        alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
            }
        });
 
        // Showing Alert Message
        alertDialog.show();
    }
}

3.I am writing all session related functions in one class to make them available in all activities. Create a new class named SessionManagement.java and add following lines of code.

SessionManagement.java
package com.androidgreeve.sessions;

import java.util.HashMap;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;

public class SessionManager {
    // Shared Preferences
    SharedPreferences pref;
    
    // Editor for Shared preferences
    Editor editor;
    
    // Context
    Context _context;
    
    // Shared pref mode
    int PRIVATE_MODE = 0;
    
    // Sharedpref file name
    private static final String PREF_NAME = "AndroidGreeve";
    
    // All Shared Preferences Keys
    private static final String IS_LOGIN = "IsLoggedIn";
    
    // User name (make variable public to access from outside)
    public static final String KEY_NAME = "name";
    
    // Email address (make variable public to access from outside)
    public static final String KEY_EMAIL = "email";
    
    // Constructor
    public SessionManager(Context context){
        this._context = context;
        pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
        editor = pref.edit();
    }


In this example i am storing login status, name, email in shared preferences, so i added a function called createLoginSession(String name, String email) to SessionManagement class. Add the following function to SessionManagement.java.

> This function simply stores login status(true), name, email in shared preferences.


 public void createLoginSession(String name, String email){
        // Storing login value as TRUE
        editor.putBoolean(IS_LOGIN, true);
        
        // Storing name in pref
        editor.putString(KEY_NAME, name);
        
        // Storing email in pref
        editor.putString(KEY_EMAIL, email);
        
        // commit changes
        editor.commit();
    }
 

5.In order to get the stored preferences data, I added a function called getUserDetails() with the following code.

> The following function will read shared preferences and returns user data in HashMap.


/**
     * Get stored session data
     * */
    public HashMap<String, String> getUserDetails(){
        HashMap<String, String> user = new HashMap<String, String>();
        // user name
        user.put(KEY_NAME, pref.getString(KEY_NAME, null));
        
        // user email id
        user.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));
        
        // return user
        return user;
    }


6. To check whether user logged in or not i added a function checkLogin() which you can call in all Activities to check user login status.

> This function simply check user login status from shared preferences and if user is not login it will redirect user to LoginActivity
/**
     * Check login method wil check user login status
     * If false it will redirect user to login page
     * Else won't do anything
     * */
    public void checkLogin(){
        // Check login status
        if(!this.isLoggedIn()){
            // user is not logged in redirect him to Login Activity
            Intent i = new Intent(_context, LoginActivity.class);
            // Closing all the Activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            
            // Add new Flag to start new Activity
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            
            // Staring Login Activity
              _context.startActivity(i);
        }
        
    }


7. Add a function called logoutUser() to clear all the data from shared preferences. Call this function when you want to logout the user.

> This function clears all session data and redirect the user to LoginActivity
/**
     * Clear session details
     * */
    public void logoutUser(){
        // Clearing all data from Shared Preferences
        editor.clear();
        editor.commit();
        
        // After logout redirect user to Loing Activity
        Intent i = new Intent(_context, LoginActivity.class);
        // Closing all the Activities
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        
        // Add new Flag to start new Activity
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        
        // Staring Login Activity
        _context.startActivity(i);
    }

SessionManagement.java
 
package com.androidgreeve.sessions;

import java.util.HashMap;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;

public class SessionManager {
    // Shared Preferences
    SharedPreferences pref;
    
    // Editor for Shared preferences
    Editor editor;
    
    // Context
    Context _context;
    
    // Shared pref mode
    int PRIVATE_MODE = 0;
    
    // Sharedpref file name
    private static final String PREF_NAME = "AndroidGreeve";
    
    // All Shared Preferences Keys
    private static final String IS_LOGIN = "IsLoggedIn";
    
    // User name (make variable public to access from outside)
    public static final String KEY_NAME = "name";
    
    // Email address (make variable public to access from outside)
    public static final String KEY_EMAIL = "email";
    
    // Constructor
    public SessionManager(Context context){
        this._context = context;
        pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
        editor = pref.edit();
    }
    
     * Create login session

    public void createLoginSession(String name, String email){
        // Storing login value as TRUE
        editor.putBoolean(IS_LOGIN, true);
        
        // Storing name in pref
        editor.putString(KEY_NAME, name);
        
        // Storing email in pref
        editor.putString(KEY_EMAIL, email);
        
        // commit changes
        editor.commit();
    } 
   
     * Check login method wil check user login status
     * If false it will redirect user to login page
     * Else won't do anything
    public void checkLogin(){
        // Check login status
        if(!this.isLoggedIn()){
            // user is not logged in redirect him to Login Activity
            Intent i = new Intent(_context, LoginActivity.class);
            // Closing all the Activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            
            // Add new Flag to start new Activity
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            
            // Staring Login Activity
            _context.startActivity(i);
        }
        
    }
        
     * Get stored session data

    public HashMap<String, String> getUserDetails(){
        HashMap<String, String> user = new HashMap<String, String>();
        // user name
        user.put(KEY_NAME, pref.getString(KEY_NAME, null));
        
        // user email id
        user.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));
        
        // return user
        return user;
    } 
    
      * Clear session details

    public void logoutUser(){
        // Clearing all data from Shared Preferences
        editor.clear();
        editor.commit();
        
        // After logout redirect user to Loing Activity
        Intent i = new Intent(_context, LoginActivity.class);
        // Closing all the Activities
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        
        // Add new Flag to start new Activity
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        
        // Staring Login Activity
        _context.startActivity(i);
    }
    
  
     * Quick check for login
     // Get Login State
    public boolean isLoggedIn(){
        return pref.getBoolean(IS_LOGIN, false);
    }
}

8. Until now we are done creating Session Management class and now we are going to learn how to use this class in your application. For this create a simple login form asking username, password.

Create a layout xml file and a class to create login form. Name the xml file as activity_login.xml and class name as LoginActivity.java

activity_login.xml
<LinearLayout 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:orientation="vertical"
    android:padding="10dip">

    <!-- Email Label -->
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Username (Enter 'test')"
        android:singleLine="true"
        android:layout_marginBottom="5dip"/>
    
    <!-- Email input text -->
    <EditText android:id="@+id/txtUsername"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dip"/>
    
    <!-- Password Label -->
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Password (Enter 'test')"
        android:layout_marginBottom="5dip"/>
    
    <!-- Password input text -->
    <EditText android:id="@+id/txtPassword"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="20dip"
        android:password="true"
        android:singleLine="true"/>
    
    <!-- Login button -->
    <Button android:id="@+id/btnLogin"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Login"/>

</LinearLayout>

For testing purpose i am checking username, password as test, test.

Once the user enters correct login details a session will be created by calling session.createLoginSession(“AndroidGreeve”, “android@greeve”) and user is redirected to MainActivity.
 
LoginActivity.java
package com.androidgreeve.sessions;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends Activity {
    
    // Email, password edittext
    EditText txtUsername, txtPassword;
    
    // login button
    Button btnLogin;
    
    // Alert  Manager
    AlertManager alert = new AlertManager();
    
    // Session Manager Class
    SessionManager session;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        
        // Session Manager
        session = new SessionManager(getApplicationContext());              
        
        // Email, Password input text
        txtUsername = (EditText) findViewById(R.id.txtUsername);
        txtPassword = (EditText) findViewById(R.id.txtPassword);
        
        Toast.makeText(getApplicationContext(), "User Login Status: " + session.isLoggedIn(), Toast.LENGTH_LONG).show();
        
        
        // Login button
        btnLogin = (Button) findViewById(R.id.btnLogin);
        
        
        // Login button click event
        btnLogin.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                // Get username, password from EditText
                String username = txtUsername.getText().toString();
                String password = txtPassword.getText().toString();
                
                // Check if username, password is filled              
                if(username.trim().length() > 0 && password.trim().length() > 0){
                    // For testing puspose username, password is checked with sample data
                    // username = test
                    // password = test
                    if(username.equals("test") && password.equals("test")){
                        
                        // Creating user login session
                        // For testing i am stroing name, email as follow
                        // Use user real data
                        session.createLoginSession("AndroidGreeve", "anroid@greeve");
                        
                        // Staring MainActivity
                        Intent i = new Intent(getApplicationContext(), MainActivity.class);
                        startActivity(i);
                        finish();
                        
                    }else{
                        // username / password doesn't match
                        alert.showAlertDialog(LoginActivity.this, "Login failed..", "Username/Password is incorrect", false);
                    }             
                }else{
                    // user didn't entered username or password
                    // Show alert asking him to enter the details
                    alert.showAlertDialog(LoginActivity.this, "Login failed..", "Please enter username and password", false);
                }
                
            }
        });
    }      
}


9. After user redirected to MainActivity, I am getting stored session data by calling getUserDetails() and displayed in textviews.

> session.checkLogin() is called to check user login status. Here if user is not login he will be redirected to LoginActivity.java
> If user is logged in, user details are fetched by calling session.getUserDetails() and displayed in textviews.
> Also I have logout button which invokes a function session.logoutUser() to clear the session data.

 
Layout code for activity_main.xml
activity_main.xml
<LinearLayout 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:orientation="vertical"
    android:padding="10dip">
    
    <!-- Name Label -->
    <TextView
        android:id="@+id/lblName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:layout_marginTop="40dip"
        android:layout_marginBottom="10dip"/>

    <!-- Email Label -->
    <TextView
        android:id="@+id/lblEmail"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:layout_marginBottom="40dip"/>
    
    <!-- Button to show session data -->
    <Button android:id="@+id/btnLogout"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Logout"/>
</LinearLayout>
 
 MainActivity.java
package com.androidgreev.sessions;

import java.util.HashMap;

import android.app.Activity;
import android.os.Bundle;
import android.text.Html;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    
    // Alert  Manager
    AlertManager alert = new AlertManager();
    
    // Session Manager Class
    SessionManager session;
    
    // Button Logout
    Button btnLogout;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        // Session class instance
        session = new SessionManager(getApplicationContext());
        
        TextView lblName = (TextView) findViewById(R.id.lblName);
        TextView lblEmail = (TextView) findViewById(R.id.lblEmail);
        
        // Button logout
        btnLogout = (Button) findViewById(R.id.btnLogout);
        
        Toast.makeText(getApplicationContext(), "User Login Status: " + session.isLoggedIn(), Toast.LENGTH_LONG).show();
        
        
        /**
         * Call this function whenever you want to check user login
         * This will redirect user to LoginActivity is he is not
         * logged in
         * */
        session.checkLogin();
if (!session.isLoggedIn()) {
finish();
}        
        // get user data from session
        HashMap<String, String> user = session.getUserDetails();
        
        // name
        String name = user.get(SessionManager.KEY_NAME);
        
        // email
        String email = user.get(SessionManager.KEY_EMAIL);
        
        // displaying user data
        lblName.setText(Html.fromHtml("Name: <b>" + name + "</b>"));
        lblEmail.setText(Html.fromHtml("Email: <b>" + email + "</b>"));
        
        
        /**
         * Logout button click event
         * */
        btnLogout.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                // Clear the session data
                // This will clear all session data and
                // redirect user to LoginActivity
                session.logoutUser();
            }
        });
    }
        
}


10. Open AndroidManifest.xml file, add the following code and run the project.
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.androidgreeve.sessions"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="Dashboard Screen" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
        <!-- DashBoard / MainActivity -->
        <activity
            android:name=".LoginActivity"
            android:label="User Login" >
        </activity>
    </application>

</manifest>

11.Run The project  as android application

So this completed the description of  Shared Preference.If u have any doubt just post in the comments.

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