Add Menu does not let see my Android fragments

I'm starting with fragments and I have a small app with 2 fragments type tabs, I wanted to add a side menu which I could also do correctly, the error comes at the time of wanting to have the 2 things, if I put the menu the fragments they do not appear, and if I remove the menu if the fragments appear, I leave my main class a bit,

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


        Toolbar mToolbar =  findViewById(R.id.toolbar);
        setSupportActionBar(mToolbar);
        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);

        final ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, mToolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);

        drawer.bringToFront();
        drawer.requestLayout();
        drawer.setDrawerListener(toggle);
        toggle.syncState();


        navigationView.bringToFront();
        navigationView.requestLayout();
        navigationView.setNavigationItemSelectedListener(this);
        navigationView.setItemIconTintList(null);


//        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
//        setSupportActionBar(toolbar);
//        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);




    }'

// Métodos de la interfaz ActionBar.TabListener
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    mViewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {

}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {

}

// Métodos de la interfaz ViewPager.OnPageChangeListener
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}

@Override
public void onPageSelected(int position) {
    getSupportActionBar().setSelectedNavigationItem(position);
}

@Override
public void onPageScrollStateChanged(int state) {

}

@Override
public boolean onNavigationItemSelected(MenuItem item) {
    return false;
}

/**
 * A placeholder fragment containing a simple view.

public static class PlaceholderFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.

    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    /**
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

}
     */

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {

        Fragment tabFragment = null;

        switch (position){
            case 0:
                tabFragment = new TabAFragment();
                break;
            case 1:
                tabFragment = new TabBFragment();
                break;
        }
        return tabFragment;
    }

    @Override
    public int getCount() {
        // Show 2 total pages.
        return 2;
    }

    @Override
    public CharSequence getPageTitle(int position) {

        String section = null;

        switch (position) {
            case 0:
                section =  "Servicio en Curso";
                break;
            case 1:
                section = "Ficha Técnica";
                break;
        }
        return section;
    }
}

My sight

 <?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    >
    <android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/drawer_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        android:background="@color/white">
        <android.support.design.widget.NavigationView
            android:id="@+id/nav_view"
            android:layout_width="330dp"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            app:itemTextColor="@color/HintHomeMonto"
            android:fitsSystemWindows="true"
            app:headerLayout="@layout/nav_header_main"
            app:menu="@menu/activity_main_drawer"
            android:background="@color/white"
            />



    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/black"
        android:theme="@style/AppTheme.AppBarOverlay">

        <RelativeLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@color/black"
                app:layout_scrollFlags="scroll|enterAlways"
                app:popupTheme="@style/AppTheme.PopupOverlay">

            </android.support.v7.widget.Toolbar>
            <ImageView
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:layout_centerHorizontal="true"
                android:layout_centerVertical="true"
                android:background="@mipmap/audilogo"/>
        </RelativeLayout>
        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

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

    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
    </android.support.v4.widget.DrawerLayout>
</android.support.design.widget.CoordinatorLayout>

If I mention the fragments part of the menu if they appear correctly, if I leave the menu the menu appears correctly but not the fragments from now thanks