Deleting all SharedPreferences upon logout

Question

I want my application to delete all preferences when the user logs out and bring up the LoginActivity after exiting the main screen. I've been following the suggestions here. In my way, I get only the default preferences.

The workflow of my app goes this way if it helps:

Login -> Save User Details to Preferences -> Start MainActivity -> Logout -> Clear Preferences -> Start LoginActivity

Is the problem caused by using the default preferences? Or is it because I called finish()? I've tried apply() and commit(). Neither worked. The preferences still exist when I tried accessing them in the LoginActivity. How do I clear my preferences?

private void logout(){
    // clear preferences
    SharedPreferences sharedPreferences = this.getPreferences(Context.MODE_PRIVATE);
    sharedPreferences.edit().clear().apply();
    Intent i = new Intent(this, LoginActivity.class);
    startActivity(i); // call LoginActivity and finish this one.
    finish();
}

Possible duplicate of [Deleting shared preferences](https://stackoverflow.com/questions/3687315/deleting-shared-preferences) — akhilesh0707, Sep 11 '18 at 12:06
@akhilesh0707 I mentioned that I've tried that post. It didn't work though. — Donovan Keating, Sep 11 '18 at 12:09
problem is that you are not clearing the exact preference file — Qasim, Sep 11 '18 at 12:15
@DonovanKeating You need to add how you are creating preference file and how are you reading it. What makes you think that shared preference is not clear. There may be chances in reading the preference i guess. — Shubham AgaRwal, Sep 11 '18 at 12:17

sasikumar · Answer 1 · 2018-09-12T04:20:57.173

2

Use commit

SharedPreferences sharedPreferences =  getSharedPreferences("YourKey", MODE_PRIVATE);
sharedPreferences.edit().clear().commit();
Intent i = new Intent(this, LoginActivity.class);
startActivity(i);
finish();

edited Sep 12 '18 at 04:20

answered Sep 11 '18 at 12:05

sasikumar

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How is this diffferent from OP question – Shubham AgaRwal Sep 11 '18 at 12:15
@Killer refer https://stackoverflow.com/questions/5960678/whats-the-difference-between-commit-and-apply-in-shared-preference – sasikumar Sep 11 '18 at 12:17
Alright, you are pointing out apply v/s commit issue. I think an explanation would be nice. Plus i am not sure this the issue. – Shubham AgaRwal Sep 11 '18 at 12:19

score 2 · Accepted Answer · answered Sep 11 '18 at 12:20

Problem is that you are using getPreferences() instead of getSharedPreferences() or getDefaultSharedPreferences().

getPreferences() Retrieve a SharedPreferences object for accessing preferences that are private to this activity. This simply calls the underlying ContextWrapper.getSharedPreferences(String, int) method by passing in this activity's class name as the preferences name.

Since, getPreferences() uses class name as it's preference file name, thus you are inserting in one Activity pref file, and clearing another one.

See this for more detail: https://developer.android.com/reference/android/app/Activity#getPreferences(int)

This worked! Thanks man! I shouldn't have been using getPreferences() for my case. — Donovan Keating, Sep 11 '18 at 14:49

score 0 · Answer 3 · answered Sep 11 '18 at 12:17

I would suggest you to use a library like Easy Prefs to handle Sharedprefrences. It has a method Prefs.clear() so basically this would clear all the shared prefs. This would make it pretty easy for you to handle sharedPrefs.

Alternatively you can clear sharedpref by the following function-:

public void clearPrefs(){
    SharedPreferences mySPrefs = PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor editor = mySPrefs.edit();
    editor.clear();
    editor.apply();
}

Deleting all SharedPreferences upon logout

3 Answers3