title: Navigation Drawer error while opening a new fragment
body: <p>My code: </p>
  
  <p>MainActivity.java:</p>
  
  <pre><code>mainDrawerLayout = (DrawerLayout) findViewById(R.id.drawer);
      mainDrawerToggle = new ActionBarDrawerToggle(this, mainDrawerLayout, R.string.open, R.string.close);
  
      mainDrawerLayout.addDrawerListener(mainDrawerToggle);
      mainDrawerToggle.syncState();
      getSupportActionBar().setDisplayHomeAsUpEnabled(true);
      setupDrawerContent();
  
  Fragment myFragment = null;
      Class fragmentClass;
      switch (menuItem.getItemId()) {
          case R.id.nav_aboutus;
              fragmentClass = AboutUs.class;
              break;
              default:
                  fragmentClass = AboutUs.class;
      }
      try {
          myFragment = (Fragment) fragmentClass.newInstance();
      }
      catch (Exception e) {
          e.printStackTrace();
      }
      FragmentManager fragmentManager = getSupportFragmentManager();
      fragmentManager.beginTransaction().replace(R.id.flcontent,myFragment).commit();
      menuItem.setChecked(true);
      setTitle(menuItem.getTitle());
      mainDrawerLayout.closeDrawers();
  }
      private void setupDrawerContent(NavigationView navigationView) {
      navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
          @Override
          public boolean onNavigationItemSelected(@NonNull MenuItem item) {
              selectItemDrawer(item);
              return false;
          }
      });
  </code></pre>
  
  <p>When I trying this method, I don't know what can I write to  ""setupDrawerContent();"" here.... and here "<code>case R.id.nav_aboutus;</code>" I have this error:  "<code>Error:(48, 34) error: : expected</code>"</p>
  
  <p><em>Edit</em>
  I started the whole app in "Blank Activity"</p>
  
  <p>Can anyone help me?
  Thanks..</p>
  
  <p><em>EDIT2</em> :  <a href="http://www.mediafire.com/file/i0gn3qgcbw4c5jn/TheWhole%20Code.rar" rel="nofollow noreferrer">http://www.mediafire.com/file/i0gn3qgcbw4c5jn/TheWhole%20Code.rar</a></p>