注销片段无法正常工作

Question

我有2个活动，一个是通过facebook登录，另一个是家庭活动。我在家庭活动中有一个导航抽屉，其中包含一个名为Logout的项目。我希望新用户通过第一个活动登录，如果他们已经登录，则转到主页活动，然后单击主页活动导航栏中的注销，退出并重定向到登录活动。

这是我的登录活动：

package com.pipipzz.simpleapp;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;

import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.login.LoginManager;
import com.facebook.login.LoginResult;

import java.util.Arrays;


public class NewLoginActivity extends Activity {

    public static CallbackManager callbackManager;
    public boolean signedIn;
    public SharedPreferences sharedPreferences;
    //public ProfileTracker profileTracker;

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

        // Initialize SDK before setContentView(Layout ID)
        FacebookSdk.sdkInitialize(getApplicationContext());

        sharedPreferences = getPreferences(Context.MODE_PRIVATE);
        signedIn = sharedPreferences.getBoolean("signedin", false);
        if(signedIn) {
            Intent intent = new Intent(NewLoginActivity.this, HomeActivity.class);
            startActivity(intent);
            //finish();
        }

        setContentView(R.layout.activity_new_login);

        // Initialize layout button
        ImageView button = (ImageView) findViewById(R.id.login_button);

        button.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // Call private method
                onFblogin();
            }
        });
    }

    private void onFblogin()
    {
        callbackManager = CallbackManager.Factory.create();

        // Set permissions
        LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("email", "user_photos", "public_profile"));

        LoginManager.getInstance().registerCallback(callbackManager,
                new FacebookCallback<LoginResult>() {
                    @Override
                    public void onSuccess(LoginResult loginResult) {
                        Log.d("Login Result", "Success");
                        signedIn = true;
                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        editor.putBoolean("signedin", signedIn);
                        editor.apply();
                        Intent intent = new Intent(NewLoginActivity.this, HomeActivity.class);
                        startActivity(intent);
                        //finish();
                    }

                    @Override
                    public void onCancel() {
                        Log.d("Login Result", "On cancel");
                    }

                    @Override
                    public void onError(FacebookException error) {
                        Log.d("Login Result", error.toString());
                    }
                });

//        profileTracker = new ProfileTracker() {
//            @Override
//            protected void onCurrentProfileChanged(Profile profile, Profile profile1) {
//                Log.e("oldProfile", profile.getName());
//            }
//        };
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        callbackManager.onActivityResult(requestCode, resultCode, data);
        //Intent intent = new Intent(NewLoginActivity.this, HomeActivity.class);
        //startActivity(intent);
    }

}

我正在尝试使用sharedprefrence来存储登录状态。这是我的家庭活动：

package com.pipipzz.simpleapp;

import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;


public class HomeActivity extends AppCompatActivity {

    Toolbar toolbar;
    ViewPager viewPager;
    ViewPagerAdapter viewPagerAdapter;
    SlidingTabLayout slidingTabLayout;
    CharSequence Titles[] = {"Following", "Trending"};
    int numOfTabs = 2;

    private ActionBarDrawerToggle drawerToggle;
    private DrawerLayout mDrawer;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

        //Initialise views
        viewPager = (ViewPager) findViewById(R.id.pager);
        slidingTabLayout = (SlidingTabLayout) findViewById(R.id.tabs);
        toolbar = (Toolbar) findViewById(R.id.toolbar1);

        setSupportActionBar(toolbar);
        final ActionBar ab = getSupportActionBar();
        assert ab != null;

        ab.setHomeButtonEnabled(true);
        ab.setDisplayHomeAsUpEnabled(true);
        ab.setHomeAsUpIndicator(R.drawable.menu);

        viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager(), Titles, numOfTabs);
        viewPager.setAdapter(viewPagerAdapter);
        slidingTabLayout.setDistributeEvenly(true);
        slidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                //return Color.parseColor("#88ffffff");
                return Color.parseColor("#FAC80A");
            }
        });
        slidingTabLayout.setViewPager(viewPager);

        if (android.os.Build.VERSION.SDK_INT >= 21)
        {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            window.setStatusBarColor(Color.parseColor("#263238"));
        }

        FloatingActionButton button = (FloatingActionButton) findViewById(R.id.ddd);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(HomeActivity.this, ImageGridActivity.class);
                startActivity(intent);
            }
        });

        // Find our drawer view
        mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawerToggle = setupDrawerToggle();
        drawerToggle.setDrawerIndicatorEnabled(false);
        toolbar.setNavigationIcon(R.drawable.menu);
        mDrawer.setDrawerListener(drawerToggle);


        // Find our drawer view
        NavigationView nvDrawer = (NavigationView) findViewById(R.id.nvView);
        // Setup drawer view
        setupDrawerContent(nvDrawer);

        toolbar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mDrawer.openDrawer(Gravity.LEFT);
            }
        });

    }


    private ActionBarDrawerToggle setupDrawerToggle() {
        return new ActionBarDrawerToggle(this, mDrawer, toolbar, R.string.drawer_open,  R.string.drawer_close);
    }

    private void setupDrawerContent(NavigationView navigationView) {
        navigationView.setNavigationItemSelectedListener(
                new NavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(MenuItem menuItem) {
                        selectDrawerItem(menuItem);
                        return true;
                    }
                });
    }

    public void selectDrawerItem(MenuItem menuItem) {
        // Create a new fragment and specify the planet to show based on
        // position
        Fragment fragment = null;

        Class fragmentClass;
        switch(menuItem.getItemId()) {
            case R.id.nav_first_fragment:
                fragmentClass = MyFeedFragment.class;
                break;
            case R.id.nav_second_fragment:
                fragmentClass = SurpriseMeFragment.class;
                break;
            case R.id.nav_third_fragment:
                fragmentClass = GalleriesFragment.class;
                break;
            case R.id.nav_fourth_fragment:
                fragmentClass = MyProfileFragment.class;
                break;
            case R.id.nav_fifth_fragment:
                fragmentClass = MessagesFragment.class;
                break;
            case R.id.nav_settings:
                fragmentClass = SettingsFragment.class;
                break;
            case R.id.nav_logout:
                fragmentClass = LogoutFragment.class;
                break;
            default:
                fragmentClass = MyFeedFragment.class;
        }

        try {
            fragment = (Fragment) fragmentClass.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }

        // Insert the fragment by replacing any existing fragment
        FragmentManager fragmentManager = this.getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.flContent, fragment).addToBackStack(null).commit();

        // Highlight the selected item, update the title, and close the drawer
        menuItem.setChecked(true);
        //setTitle(menuItem.getTitle());
        mDrawer.closeDrawers();
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        //getMenuInflater().inflate(R.menu.menu_home, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home:
                mDrawer.openDrawer(GravityCompat.START);
                return true;
        }

//        if (drawerToggle.onOptionsItemSelected(item)) {
//            return true;
//        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        drawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggles
        drawerToggle.onConfigurationChanged(newConfig);
    }

我不想在导航抽屉中点击退出时绘制任何UI，因此我创建了一个无用于注销的UI片段：

package com.pipipzz.simpleapp;


import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;

import com.facebook.AccessToken;
import com.facebook.login.LoginManager;


/**
 * A simple {@link Fragment} subclass.
 */
public class LogoutFragment extends Fragment {

    public LogoutFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
        if(AccessToken.getCurrentAccessToken() != null) {
            LoginManager.getInstance().logOut();
        }
        SharedPreferences sharedPreferences = getActivity().getPreferences(Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        //editor.clear();
        editor.putBoolean("signedin", false);
        editor.apply();
        Intent intent = new Intent(getActivity(), NewLoginActivity.class);
        startActivity(intent);
    }

}

在执行上述操作后，我可以注销facebook，但我无法重定向到登录活动。我经常搜索，但找不到任何东西。可能是什么问题？请帮忙。