（Android）NavigationDrawer不指向所选片段

Question

有人能告诉我导航抽屉上的问题吗？它没有指向示例SenftFragment和DraftFragment来查看布局。这是代码。

MainActivity.java

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


        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        viewPager = (ViewPager) findViewById(R.id.viewPager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);//setting tab over viewpager

        mDrawerLayout =(DrawerLayout)findViewById(R.id.drawerLayout);
        mNavigationView = (NavigationView)findViewById(R.id.shitstuff);

        mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {
                mDrawerLayout.closeDrawers();

                if (menuItem.getItemId() == R.id.nav_item_sent) {


                    getSupportFragmentManager().beginTransaction().add(R.id.containerView,new SentFragment()).commit();
                    Toast.makeText(getApplicationContext(), "Sent!",
                            Toast.LENGTH_SHORT).show();

                }
                if (menuItem.getItemId() == R.id.nav_item_draft) {

                    mFragmentManager = getSupportFragmentManager();
                    FragmentTransaction ft_drafts = mFragmentManager.beginTransaction();
                    ft_drafts.replace(R.id.containerView, new DraftFragment()).commit();

                    Toast.makeText(getApplicationContext(), "Drafts!", Toast.LENGTH_SHORT).show();
                }


                return true;
            }

        });
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawerLayout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        android:orientation="vertical">


        <android.support.design.widget.CoordinatorLayout android:id="@+id/coordinatorLayout"
            xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:app="http://schemas.android.com/apk/res-auto"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">



            <android.support.design.widget.AppBarLayout

                android:id="@+id/appBarLayout"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

                <FrameLayout
                    android:id="@+id/containerView"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:orientation="vertical">
                </FrameLayout>

                <android.support.v7.widget.Toolbar
                    android:id="@+id/toolbar"
                    android:layout_width="fill_parent"
                    android:layout_height="?attr/actionBarSize"
                    android:background="?attr/colorPrimary"
                    android:title="Android Testing"
                    app:layout_scrollFlags="scroll|enterAlways"
                    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>
                <!-- Tab Layout for creating tabs -->
                <android.support.design.widget.TabLayout
                    android:id="@+id/tabs"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="@color/material_blue_grey_800"
                    app:tabGravity="fill"
                    app:tabIndicatorColor="@color/main_color"
                    app:tabMode="fixed"
                    app:tabSelectedTextColor="@color/main_color"
                    app:tabTextColor="@color/white">

                </android.support.design.widget.TabLayout>
                <!-- Helps handing the Fragments for each Tab -->
            </android.support.design.widget.AppBarLayout>

            <android.support.v4.view.ViewPager
                android:id="@+id/viewPager"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

        </android.support.design.widget.CoordinatorLayout>

    </LinearLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/shitstuff"
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:layout_marginTop="-24dp"
        app:itemTextColor="@color/black"
        app:menu="@menu/drawermenu"/>

</android.support.v4.widget.DrawerLayout>