Android - Facebook SDK login & # 8594; logout & # 8594; login not working

Question

I have an Android app (very simple, just starting to learn the basics). I implemented a Facebook login that works almost perfectly. At the first launch of the application, everything works very well: pressing the login button, requesting permissions, logging in, the application displays an authentication page for the user. When you click the logout button, the login page is displayed again, so this also works. Now when I try to log in, it does not work. He reopens the facebook material in a few seconds, after which he simply returns to the login page as if nothing had happened. If I remove the Facebook permissions for the application and try to log in, it will work again. So for some reason I can’t log in when I already have permission,which I guess ...

Here is the code:

package com.just.simply.myapplication;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.Menu;
import android.view.MenuItem;

import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;

public class MyActivity extends FragmentActivity {

    private static final int SPLASH = 0;
    private static final int SELECTION = 1;
    private static final int SETTINGS = 2;
    private static final int FRAGMENT_COUNT = SETTINGS + 1;

    private Fragment[] fragments = new Fragment[FRAGMENT_COUNT];

    private boolean isResumed = false;
    private MenuItem settings;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        uiHelper = new UiLifecycleHelper(this, callback);
        uiHelper.onCreate(savedInstanceState);

        setContentView(R.layout.activity_my);

        FragmentManager fm = getSupportFragmentManager();
        fragments[SPLASH] = fm.findFragmentById(R.id.splashFragment);
        fragments[SELECTION] = fm.findFragmentById(R.id.selectionFragment);
        fragments[SETTINGS] = fm.findFragmentById(R.id.userSettingsFragment);

        FragmentTransaction transaction = fm.beginTransaction();
        for(int i = 0; i < fragments.length; i++) {
            transaction.hide(fragments[i]);
        }
        transaction.commit();
    }

    @Override
    public void onResume() {
        super.onResume();
        uiHelper.onResume();
        isResumed = true;
    }

    @Override
    public void onPause() {
        super.onPause();
        uiHelper.onPause();
        isResumed = false;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        uiHelper.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        uiHelper.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        uiHelper.onSaveInstanceState(outState);
    }

    private void onSessionStateChange(Session session, SessionState state, Exception exception) {
        // Only make changes if the activity is visible
        if (isResumed) {
            FragmentManager manager = getSupportFragmentManager();
            // Get the number of entries in the back stack
            int backStackSize = manager.getBackStackEntryCount();
            // Clear the back stack
            for (int i = 0; i < backStackSize; i++) {
                manager.popBackStack();
            }
            if (state.isOpened()) {
                // If the session state is open:
                // Show the authenticated fragment
                showFragment(SELECTION, false);
            } else if (state.isClosed()) {
                // If the session state is closed:
                // Show the login fragment
                showFragment(SPLASH, false);
            }
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.equals(settings)) {
            showFragment(SETTINGS, true);
            return true;
        }
        return false;
    }

    @Override
    protected void onResumeFragments() {
        super.onResumeFragments();
        Session session = Session.getActiveSession();

        if (session != null && session.isOpened()) {
            // if the session is already open,
            // try to show the selection fragment
            showFragment(SELECTION, false);
        } else {
            // otherwise present the splash screen
            // and ask the person to login.
            showFragment(SPLASH, false);
        }
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // only add the menu when the selection fragment is showing
        if (fragments[SELECTION].isVisible()) {
            if (menu.size() == 0) {
                settings = menu.add(R.string.settings);
            }
            return true;
        } else {
            menu.clear();
            settings = null;
        }
        return false;
    }

    private UiLifecycleHelper uiHelper;
    private Session.StatusCallback callback =
            new Session.StatusCallback() {
                @Override
                public void call(Session session,
                                 SessionState state, Exception exception) {
                    onSessionStateChange(session, state, exception);
                }
            };

    private void showFragment(int fragmentIndex, boolean addToBackStack) {
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction transaction = fm.beginTransaction();
        for (int i = 0; i < fragments.length; i++) {
            if (i == fragmentIndex) {
                transaction.show(fragments[i]);
            } else {
                transaction.hide(fragments[i]);
            }
        }
        if (addToBackStack) {
            transaction.addToBackStack(null);
        }
        transaction.commit();
    }
}

Any help would be appreciated! If you need other files, just ask.

Thank!