Android未清除SharedPreferences

Question

I have an app where a user logs in and his details are saved so that the next time he starts the app he doesn't need to log in again.I have used SharedPreferences for this purpose. Now when I implement a logout function, I clear the preferences and I get a Map with 0 elements. Also I delete the Preference file. But when another user logs in he can still see the previous users details instead of his. How can I solve this?

Here is my code:-

SessionManagement.java

public class SessionManagement extends Application
{
    static SharedPreferences pref;

    // Editor for Shared preferences
    SharedPreferences.Editor editor;

    // ContextS
    Context _context;

    // Shared pref mode
    int PRIVATE_MODE = 0;

    // Sharedpref file name
    private static final String PREF_NAME = "MyUserDetails";

    // 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_EMAILID = "email";

    // Email address (make variable public to access from outside)

    public static final String KEY_USERSNAME = "usersname";


    public static final String  KEY_DEVICEREGISTERED = "deviceregistered";
    // Constructor


    public SessionManagement(Context context)
    {
        this._context = context;
        pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
        editor = pref.edit();
    }


    public void createLoginSession(String emailId, String usersname)
    {
        // Storing login value as TRUE
        editor.putBoolean(IS_LOGIN, true);

        editor.putBoolean(KEY_DEVICEREGISTERED, true);
        editor.putString(KEY_EMAILID, emailId);

        editor.putString(KEY_USERSNAME, usersname);

        editor.commit();

        // commit changes

    }


    /**
     * Get stored session data
     * */
    public HashMap<String, String> getUserDetails()
    {
        HashMap<String, String> user = new HashMap<String, String>();

        user.put(KEY_EMAILID, pref.getString(KEY_EMAILID, null));

        user.put(KEY_USERSNAME, pref.getString(KEY_USERSNAME, null));

        // return user
        return user;

    }


    /**
     * 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(this, Login.class);
            // Closing all the Activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);

            // Add new Flag to start new Activity
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            // Staring Login Activity
            _context.startActivity(i);

        }

    }


    // 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.remove(KEY_EMAILID);
        editor.remove(KEY_USERSNAME);
        editor.remove(IS_LOGIN);

        editor.clear();
        editor.commit();

    }

    public boolean isLoggedIn()
    {
        return pref.getBoolean(IS_LOGIN, false);
    }
}

Login.java

sessionManager = new SessionManagement(getApplicationContext());

if(sessionManager.isLoggedIn())
{
    //Go directly to main activity
    HashMap<String, String> userDetails = sessionManager.getUserDetails();

    startMyActivity();
    finish();
}
else
{
    sessionManager.createLoginSession(email, username);
}
public void startMyActivity()
{
    // TODO Auto-generated method stub
    Intent in = new Intent(getApplicationContext(), Details1.class);

    in.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    startActivity(in);
    finish();
}

Logout.java

SessionManagement session = new SessionManagement(getApplicationContext());
session.logoutUser();

ClearData cl = new ClearData();
cl.clearApplicationData(getApplicationContext());

Intent i = new Intent(Home.this, Login.class);
// Closing all the Activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);

// Add new Flag to start new Activity
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

// Staring Login Activity
startActivity(i);

ClearData.java

public class ClearData
{
    public static void clearApplicationData(Context context)
    {
        File cache = context.getCacheDir();
        File appDir = new File(cache.getParent());
        if (appDir.exists()) {
            String[] children = appDir.list();
            for (String s : children) {
                File f = new File(appDir, s);
                if(deleteDir(f))
                    Log.i("TAG", String.format("**************** DELETED -> (%s) *******************", 
                            f.getAbsolutePath()));
            }
        }
    }
    private static boolean deleteDir(File dir) {
        if (dir != null && dir.isDirectory()) {
            String[] children = dir.list();
            for (int i = 0; i < children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }
        return dir.delete();
    }
}

Answer 1

Instead of removing value from sharedpreference you can just edit value of sharedpreference with null value.

       public void logoutUser()
       { 
           editor.putBoolean(IS_LOGIN, false);
           editor.putBoolean(KEY_DEVICEREGISTERED, false);
           editor.putString(KEY_EMAILID, null);
           editor.putString(KEY_USERSNAME, null);
           editor.commit();
        }

i think this will work..

Answer 2

You can change the values of Shared preferences.

public void logoutUser()
   { 
       editor.putBoolean(IS_LOGIN, false);
       editor.putBoolean(KEY_DEVICEREGISTERED, false);
       editor.putString(KEY_EMAILID, "");
       editor.putString(KEY_USERSNAME, "");
       editor.clear();
       editor.commit();
    }

or You try this code. Clear your Shared preferences values.

pref.edit().clear().commit();

Answer 3

if your are using Marshmallow then Add file in xml folder mybackupscheme.xml

    <full-backup-content>
         <exclude domain="sharedpref" path="yourshared pref name.xml"/>
    </full-backup-content>

then add in AndroidManifest.xml

<application
...
android:fullBackupOnly="false"
android:fullBackupContent="@xml/mybackupscheme"
/>

Hope this using this your issue will be resolved.

Answer 4

Try to get editor every time before calling commit(). If this not works, check contexts, that are returning preferences, they must be in one application and process.

I think problem is in your way of working with editor.

Answer 5

I think there is problem in your view of your editor and preference globalization you have to create preference and editor locally.... Because you are getting preferences

public SessionManagement(Context context)
{
    this._context = context;
    pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = pref.edit();
}

And now you are not getting any updated Preferences.... Each and every time when you have to work with your preferences... Initialize preference and editor every time.

Either logging In or log out.