Right now I am trying to create one Android application, assume it is going to be some "X" concept okay. So I am creating one login screen. What I want to do is at once if I logged in that application on my mobile, it should always be logged in whenever I try to access that application.
For example our Facebook, g-mail and yahoo etc.. in our mobile phones
What to do for that?
Use Shared Preference for auto login functionality. When users log in to your application, store the login status into sharedPreference and clear sharedPreference when users log out.
Check every time when the user enters into the application if user status from shared Preference is true then no need to log in again otherwise direct to the login page.
To achieve this first create a class, in this class you need to write all the function regarding the get and set value in the sharedpreference. Please look at this below Code.
public class SaveSharedPreference
{
static final String PREF_USER_NAME= "username";
static SharedPreferences getSharedPreferences(Context ctx) {
return PreferenceManager.getDefaultSharedPreferences(ctx);
}
public static void setUserName(Context ctx, String userName)
{
Editor editor = getSharedPreferences(ctx).edit();
editor.putString(PREF_USER_NAME, userName);
editor.commit();
}
public static String getUserName(Context ctx)
{
return getSharedPreferences(ctx).getString(PREF_USER_NAME, "");
}
}
Now in the main activity (The "Activity" where users will be redirected when logged in) first check
if(SaveSharedPreference.getUserName(MainActivity.this).length() == 0)
{
// call Login Activity
}
else
{
// Stay at the current activity.
}
In Login activity if user login successful then set UserName using setUserName() function.
You may add the following for logout operation in your SaveSharedPreference.java :
public static void clearUserName(Context ctx)
{
Editor editor = getSharedPreferences(ctx).edit();
editor.clear(); //clear all stored data
editor.commit();
}
Always and whenever ... so this seems like an automated login approach. The application starts, the user doesn't have to login again once he has provided his authorization information. There are several ways to achieve this. The Facebook API e.g. provides mechanism for login without the use of a form element. So you would basically have to construct a view in which the user can provide his authorization information once, store them in SharedPreferences and login automatically the next time. Even if there is no such API - based login and you have to use a login - form provided, you sometimes could simulate the POST - request for logging in. This depends on the actual server - side implementation of that form. But remember: This is an security issue. So never store authorization credentials in clear text format. Don't rely on crypting it by a defined key in your application as this key maybe detected by reverse engineering your APK. Instead use many collective informations about the device and a key the user has to enter or is randomly generated and stored by the app.
I am surprised no answer mentions AccountManager. It is the official and correct way to find out if your user is really who he/she claimed to be. In order to use it, you have to get permission by adding this in your manifest file :
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
Then you get an array of Accounts using this (in case you want user to use his/her Google account) :
AccountManager am = AccountManager.get(this);
Account[] accounts = am.getAccountsByType("com.google");
Full reference here : AccountManager
Using SharedPreferences is a way to save and retrieve key-value pair data in Android and also to keep the session throughout the entire application.
To work with SharedPreferences you need to take the following steps:
// Sharedpref file name
private static final String PREF_NAME = "PreName";
// Shared pref mode
int PRIVATE_MODE = 0;
//Initialising the SharedPreferences
SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0); // 0 - for private mode
//Initialising the Editor
Editor editor = pref.edit();
editor.putBoolean("key_name", true); // Storing boolean - true/false
editor.putString("key_name", "string value"); // Storing string
editor.putInt("key_name", "int value"); // Storing integer
editor.putFloat("key_name", "float value"); // Storing float
editor.putLong("key_name", "long value"); // Storing long
editor.commit(); // commit changes
Data can be retrieved from saved preferences by calling getString() (For string) method. Remember this method should be called on Shared Preferences and not on Editor.
// returns stored preference value
// If value is not present return second param value - In this case null
pref.getString("key_name", null); // getting String
pref.getInt("key_name", null); // getting Integer
pref.getFloat("key_name", null); // getting Float
pref.getLong("key_name", null); // getting Long
pref.getBoolean("key_name", null); // getting boolean
If you want to delete from shared preferences you can call remove(“key_name”) to delete that particular value. If you want to delete all the data, call clear()
editor.remove("name"); // will delete key name
editor.remove("email"); // will delete key email
editor.commit(); // commit changes
Following will clear all the data from shared preferences
editor.clear();
editor.commit(); // commit changes
Please follow the link below to download a simple and straightforward example: http://www.androidhive.info/2012/08/android-session-management-using-shared-preferences/
I hope I haven't gone against the rules and regulations of the platform for sharing this link.
//This is my SharedPreferences Class
import java.util.HashMap;
import android.annotation.SuppressLint;
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 = "AndroidHivePref";
// 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
@SuppressLint("CommitPrefEdits")
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, MainActivity.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
checkLogin();
}
/**
* Quick check for login
**/
// Get Login State
public boolean isLoggedIn() {
return pref.getBoolean(IS_LOGIN, false);
}
}
Finally, you will have to create an instance of this SessionManager class in the onCreate method of your activity class and then call the createLoginSession for the session that will be used throughout the entire session
// Session Manager Class
SessionManager session;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Session Manager
session = new SessionManager(getApplicationContext());
session.createLoginSession("Username", intentValue);
}
I hope it helps.
Just wanted to post another solution that I found the easiest for me:
SharedPreferences sharedpreferences;
int autoSave;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//"autoLogin" is a unique string to identify the instance of this shared preference
sharedpreferences = getSharedPreferences("autoLogin", Context.MODE_PRIVATE);
int j = sharedpreferences.getInt("key", 0);
//Default is 0 so autologin is disabled
if(j > 0){
Intent activity = new Intent(getApplicationContext(), HomeActivity.class);
startActivity(activity);
}
}
public void loginBtn(View view){
//Once you click login, it will add 1 to shredPreference which will allow autologin in onCreate
autoSave = 1;
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putInt("key", autoSave);
editor.apply();
}
Now let's suppose I have a sign out button in another activity:
SharedPreferences sharedPreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
//Get that instance saved in the previous activity
sharedPreferences = getSharedPreferences("autoLogin", Context.MODE_PRIVATE);
}
@Override
public void signOut(View view) {
//Resetting value to 0 so autologin is disabled
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putInt("key", 0);
editor.apply();
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
}
after login when you press back call moveTaskToBack(true);
from this your application will be in background state. hope help
Xamarin.Android port of Chirag Raval's and LINTUism's answers:
public class SharedPreference
{
static ISharedPreferences get(Context ctx)
{
return PreferenceManager.GetDefaultSharedPreferences(ctx);
}
public static void SetUsername(Context ctx, string username)
{
var editor = get(ctx).Edit();
editor.PutString("USERNAME", username);
editor.Commit();
}
public static string GetUsername(Context ctx)
{
return get(ctx).GetString("USERNAME", "");
}
public static void Clear(Context ctx)
{
var editor = get(ctx).Edit();
editor.Clear();
editor.Commit();
}
}
So If You are using Firebase Auth there is no need of SharedPreference instead you can use.
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if(user != null){
startActivity(new Intent(LoginActivity.this, DashActivity.class)));
finish();
}
** This Method will be called if the user is logged in once**
