How to display login screen only one time?

Question

I am creating a project where I have a login screen, which is used for user to login into the
Application. This login screen should only be visible the first time, so the user can fill it and log in, but when user opens the application at the second time the application must show main.activity. How to use Shared preference.

I don't understand how to do this.

The link you tried to share with us was malformed. Please edit your question to add the correct link. — Telmo Marques, Apr 01 '12 at 13:02

Telmo Marques · Accepted Answer · 2018-03-14T17:34:57.817

38

To achieve this with SharedPreferences you might do something like this:

Insert the following in any Class you see more fit. Let's suppose you insert this in class Example.

//Give your SharedPreferences file a name and save it to a static variable
public static final String PREFS_NAME = "MyPrefsFile";

Now, in the method that evaluates if the user successfully logs in, do the following. Notice the Example class, you must change this to match your code.

//User has successfully logged in, save this information
// We need an Editor object to make preference changes.
SharedPreferences settings = getSharedPreferences(Example.PREFS_NAME, 0); // 0 - for private mode
SharedPreferences.Editor editor = settings.edit();

//Set "hasLoggedIn" to true
editor.putBoolean("hasLoggedIn", true);

// Commit the edits!
editor.commit();

Finally, when your application starts you can now evaluate if the user has already logged in or not. Still notice the Example class that you must change.

SharedPreferences settings = getSharedPreferences(Example.PREFS_NAME, 0);
//Get "hasLoggedIn" value. If the value doesn't exist yet false is returned
boolean hasLoggedIn = settings.getBoolean("hasLoggedIn", false);

if(hasLoggedIn)
{
    //Go directly to main activity.
}

Hope this helps

EDIT: To prevent the user from using the back button to go back to the Login activity you have to finish() the activity after starting a new one.

Following code taken from Forwarding.java | Android developers

// Here we start the next activity, and then call finish()
// so that our own will stop running and be removed from the
// history stack
Intent intent = new Intent();
intent.setClass(Example.this, ForwardTarget.class);
startActivity(intent);
Example.this.finish();

So, what you have to do in your code is to call the finish() function on the Login activity, after calling startActivity().

See also: Removing an activity from the history stack

edited Mar 14 '18 at 17:34

answered Apr 01 '12 at 13:27

Telmo Marques

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it show the error on (Example.PREFS_NAME, 0); and i need to add this code in which activity? – Sandip Armal Patil Apr 01 '12 at 13:57
@sandiparmal please read my answer carefully, I state where you need to insert the code. The `Example` class must be changed to match the class where you created the `PREFS_NAME` static variable. – Telmo Marques Apr 01 '12 at 14:03
1

still it jump on login even after fill the data. can i place the code? – Sandip Armal Patil Apr 01 '12 at 14:12
@sandiparmal feel free to edit your question to show us your code. If you have extensive code use something like [pastebin.com](http://pastebin.com/) to paste your code. – Telmo Marques Apr 01 '12 at 14:26
hey give me one more favour....when i press back button it still go on login page.. – Sandip Armal Patil Apr 01 '12 at 14:32
1

@sandiparmal you have to `finish()` the login activity after starting a new one. Please see my edit. – Telmo Marques Apr 01 '12 at 14:43
what about `android:noHistory="true"` flag in the `AndroidManifest.xml` ? – AlexAndro Oct 11 '13 at 14:49
@TelmoMarques I think it will ask for login again if the user updates the application even he is logged in.Am i right? – KJEjava48 Mar 08 '17 at 12:48
@TelmoMarques What is the `Example` class here ? – Mohammad Ali Mar 13 '18 at 11:24
@MohammadHamoud that's just your class, where you're implementing your code. – Telmo Marques Mar 13 '18 at 16:55
@TelmoMarques and the `Forwarding` ? – Mohammad Ali Mar 13 '18 at 16:59
@MohammadHamoud, `Forwarding` should be replaced with your login Activity. That snippet of code is used to prevent the user from using the back button to go back to the login screen after successfully logging in. – Telmo Marques Mar 14 '18 at 10:45
@TelmoMarques yes I know but I was wondering how would `Forwarding.this` and `Example.this` be in the same activity as we are using `.this` for both – Mohammad Ali Mar 14 '18 at 10:47
@MohammadHamoud that appears to be a typo that I never noticed! I've updated the response above. – Telmo Marques Mar 14 '18 at 17:35

score 1 · Answer 2 · edited May 23 '17 at 12:09

1

You should add another empty activity (with no UI) that loads before anything else.

Put the logic described by @Telmo Marques in this empty activity, which is responsible to direct the user either to the LoginScreen.Activity or to Main.Activity

see here, answer by @tozka How to Skip the first activity under a condition

edited May 23 '17 at 12:09

Community

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answered Feb 14 '14 at 18:56

kouretinho

2,190
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score 1 · Answer 3 · answered Feb 04 '17 at 10:39

Using token is also a good method to know the login status.In Oauth token based login when the user login to the application they will get back a access token on successful login and is saved in account manager in secured way.And there after when ever the user open the application first check for the availability of token and if available redirect to the main page else to the login activity.

score 1 · Answer 4 · answered Apr 01 '12 at 12:48

1

Use SharedPreferences. For example, save some value, and read it on your login Activity.

In our project we saving token and user id. So, if user is already logged in, we skip authorization Activity.

P.S. If your login Activity is the first one in your app, then don't forget to finish it, before starting another Activity, to prevent pressing "Back" key in other activities.

answered Apr 01 '12 at 12:48

Dmitry Zaytsev

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where i store this value means on which activity? – Apr 01 '12 at 12:48
user1294970 store this value when user logged in for the first time. – Abdul Basit Rishi Sep 15 '20 at 07:04

score 1 · Answer 5 · answered Apr 01 '12 at 13:53

Use SharedPreferences. For example, have a boolean variable , and read it on your application launches. In your case when user launches the app first time the variable in shared preference will be false, so launch login screen and after successfull login make that boolean variable to true in shared preference, so that when user comes secnd time the value in the shared preference will be true. so skip the login screen and launch your main activity.

To store boolean in SharedPreference use below code::

public static void saveBooleanInSP(Context _context, boolean value){
SharedPreferences preferences = _context.getSharedPreferences("PROJECTNAME", android.content.Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putBoolean("ISLOGGEDIN", value);
editor.commit();
}//savePWDInSP()

To getValue from SharedPreference use below code::

public static boolean getBooleanFromSP(Context _context) {
// TODO Auto-generated method stub
SharedPreferences preferences = _context.getSharedPreferences("PROJECTNAME", android.content.Context.MODE_PRIVATE);
return preferences.getBoolean("ISLOGGEDIN", false);
}//getPWDFromSP()

How to display login screen only one time?

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