onActivityCreated删除片段

Question

我正在尝试创建一个处理片段的应用程序。 首先，在不使用片段的情况下构建应用程序登录，它工作得很好，但我尝试更具建设性，并为我创建了一个菜单。 我试图迁移所有创建片段活动日志但我无法尝试将所有内容从一个地方传递到另一个地方。

我现在发生的事情是我有在OnCreate（Activity）中创建的动作并尝试传递onCreateView（Fragments）的所有函数但是当我从视图返回时，我没有在应用程序布局中显示应该是。

MainActivity：

import android.content.res.Configuration;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {

    private DrawerLayout mDrawer;
    private Toolbar toolbar;
    private NavigationView nvDrawer;
    private ActionBarDrawerToggle drawerToggle;

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

        //set tolbar
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //Find our drawer view
        mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawerToggle = setupDrawerContent();

        // Tie DrawerLayout events to the ActionBarToggle
        mDrawer.setDrawerListener(drawerToggle);

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

    }

    private ActionBarDrawerToggle setupDrawerContent() {
        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 = null;
        switch(menuItem.getItemId()) {
            case R.id.nav_first_fragment:
                fragmentClass = FirstFragment.class;
                break;
            case R.id.nav_second_fragment:
                fragmentClass = SecondFragment.class;
                break;
            case R.id.nav_third_fragment:
                fragmentClass = ThirdFragment.class;
                break;
            case R.id.nav_status_fragment:
                fragmentClass = LoginStatusFragment.class;
                break;
            case R.id.nav_login_fragment:
                fragmentClass = LoginFragment.class;
                break;
            case R.id.nav_register_fragment:
                fragmentClass = ThirdFragment.class;
                break;
            default:
                fragmentClass = FirstFragment.class;
        }

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

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

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // The action bar home/up action should open or close the drawer.
        if (drawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        else if (item.getItemId() == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

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

    // Make sure this is the method with just `Bundle` as the signature
    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        drawerToggle.syncState();
    }

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

}

LoginStatusFragment：

import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import java.util.HashMap;

import helper.SQLiteHandler;
import helper.SessionManager;

/**
 * Created by NB21094 on 24/11/2015.
 */
public class LoginStatusFragment extends Fragment {

    private TextView txtName;
    private TextView txtEmail;
    private Button btnLogout;
    private Context context;
    private SQLiteHandler db;
    private SessionManager session;
    private View view;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.activity_loginstatus, container, false);

        context = getActivity().getApplicationContext();

        txtName = (TextView) view.findViewById(R.id.name);
        txtEmail = (TextView) view.findViewById(R.id.email);
        btnLogout = (Button) view.findViewById(R.id.btnLogout);

        // SqLite database handler
        db = new SQLiteHandler(context);

        // session manager
        session = new SessionManager(context);

        if (!session.isLoggedIn()) {
            logoutUser();
        }

        // Fetching user details from sqlite
        HashMap<String, String> user = db.getUserDetails();

        String name = user.get("name");
        String email = user.get("email");

        // Displaying the user details on the screen
        txtName.setText(name);
        txtEmail.setText(email);

        // Logout button click event
        btnLogout.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                logoutUser();
            }
        });
        return view;
        //return inflater.inflate(R.layout.activity_loginstatus, container, false);
    }
       /**
     * Logging out the user. Will set isLoggedIn flag to false in shared
     * preferences Clears the user data from sqlite users table
     * */
    private void logoutUser() {
        session.setLogin(false);

        db.deleteUsers();

        // Launching the login activity
        /*Intent intent = new Intent(LoginStatusActivity.this, MainActivity.class);
        startActivity(intent);
        finish();*/
        changeFragment("main");
    }

    private void changeFragment(String option){
        Fragment fragment = null;

        Class fragmentClass = null;
        if(option.contains("loginstatus")){
            fragmentClass = LoginStatusFragment.class;
        } else if (option.contains("register")){
            //fragmentClass = LogoutFragment.class;
        } else if (option.contains("main")) {
            fragmentClass = FirstFragment.class;
        }

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

        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
    }

}

activity_loginstatus.xml

    <?xml version="1.0" encoding="utf-8"?>
<!--<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="${relativePackage}.${activityClass}" > -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:gravity="center"
        android:orientation="vertical" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/welcome"
            android:textSize="20dp" />

        <TextView
            android:id="@+id/name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:textColor="@color/lbl_name"
            android:textSize="24dp" />

        <TextView
            android:id="@+id/email"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="13dp" />

        <Button
            android:id="@+id/btnLogout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="40dip"
            android:background="@color/btn_logut_bg"
            android:text="@string/btn_logout"
            android:textAllCaps="false"
            android:textColor="@color/white"
            android:textSize="15dp" />
    </LinearLayout>
</LinearLayout>
<!-- </RelativeLayout> -->

你能帮帮我吗？ 布局永远不会出现，我也不知道为什么。