Открытие фрагмента NawDrawer

drawer.openDrawer(navigationView);

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);

container = (FrameLayout) findViewById(R.id.container);

@Override
    public boolean onNavigationItemSelected(MenuItem item) {
        int id = item.getItemId();
 
        if (id == R.id.пункт_меню_который_тебе_нужен) {
               FragmentManager ft = getFragmentManager().beginTransaction();
 
               ft.add(R.id.container, myFragment); // если контейнер был пустой
               // или
               ft.replace(R.id.container, myFragment); // если в контейнере был другой фрагмент
 
               ft.commit();
        }
 
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
 
    FragmentCategory fcategories;
    FragmentMarker fmarker;
    FragmentNew fnew;
    FragmentSearch fsearch;
    FragmentSend fsend;
    FragmentShare fshare;
    FragmentMain fmain;
 
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
 
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
 
        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
 
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();
 
        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
 
        fcategories = new FragmentCategory();
        fmarker = new FragmentMarker();
        fnew = new FragmentNew();
        fsearch = new FragmentSearch();
        fsend = new FragmentSend();
        fshare = new FragmentShare();
        fmain = new FragmentMain();
 
 
    }
 
 
    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }
 
    @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;
    }
 
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
 
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
 
        return super.onOptionsItemSelected(item);
    }
 
    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();
 
        FragmentTransaction ftrans = getFragmentManager().beginTransaction();
 
 
 
        if (id == R.id.nav_main) {
            ftrans.replace(R.id.container, fmain);
        } else if (id == R.id.nav_camera) {
            ftrans.replace(R.id.container, fnew);
        } else if (id == R.id.nav_gallery) {
            ftrans.replace(R.id.container, fcategories);
        } else if (id == R.id.nav_slideshow) {
            ftrans.replace(R.id.container, fsearch);
        } else if (id == R.id.nav_manage) {
            ftrans.replace(R.id.container, fmarker);
        } else if (id == R.id.nav_share) {
            ftrans.replace(R.id.container, fshare);
        } ftrans.commit();
 
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

public class FragmentMain extends android.app.Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";
 
    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;
 
    private OnFragmentInteractionListener mListener;
 
    public FragmentMain() {
        // Required empty public constructor
    }
 
    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment FragmentMain.
     */
    // TODO: Rename and change types and number of parameters
    public static FragmentMain newInstance(String param1, String param2) {
        FragmentMain fragment = new FragmentMain();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }
 
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_main, container, false);
    }
 
    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }
 
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }
 
    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }
 
    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p/>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

ftrans.replace(R.id.container, fmain);

android:id="@+id/container"

    
<FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/container">
 
</FrameLayout>

fnew = new FragmentNew();

getSupportFragmentManager().beginTransaction().add(fnew, R.id.container, null).commit();