ナビゲーションドロワーメニューの項目を隠す - Android

質問

ナビゲーションドローワがあります。あるイベントが呼ばれたとき、ナビゲーションメニューの1つをユーザに対して非表示にしたいと思います。どうすればよいでしょうか。

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sliding_menu);

    if (android.os.Build.VERSION.SDK_INT > 9) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }
    mTitle = mDrawerTitle = getTitle();

    // load slide menu items
    navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

    // nav drawer icons from resources
    navMenuIcons = getResources()
            .obtainTypedArray(R.array.nav_drawer_icons);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout1);
    mDrawerList = (ListView) findViewById(R.id.list_slidermenu1);

    navDrawerItems = new ArrayList<NavDrawerItem>();

    // adding nav drawer items to array
    // Home
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
    // Profil
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
    // Prospek
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
    // Announcement
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1), true,
            cariTotal("http://192.168.0.23/api/android/announcement/").toString()));
    // Logout
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));

    // Recycle the typed array
    navMenuIcons.recycle();
    //set event
    mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
    // setting the nav drawer list adapter
    adapter = new NavDrawerListAdapter(getApplicationContext(),
            navDrawerItems);
    mDrawerList.setAdapter(adapter);
    // enabling action bar app icon and behaving it as toggle button
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeButtonEnabled(true);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
            R.string.app_name,
            R.string.app_name
    ){
        public void onDrawerClosed(View view) {
            getSupportActionBar().setTitle(mTitle);
            // calling onPrepareOptionsMenu() to show action bar icons
            invalidateOptionsMenu();
        }

        public void onDrawerOpened(View drawerView) {
            getSupportActionBar().setTitle(mDrawerTitle);
            //mDrawerList.bringToFront();
            //mDrawerLayout.requestLayout();
            // calling onPrepareOptionsMenu() to hide action bar icons
            invalidateOptionsMenu();
        }
    };
    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null) {
        // on first time display view for first nav item
        displayView(0);
    }
}
private void displayView(int position) {
    // update the main content by replacing fragments
    android.app.Fragment fragment = null;
    switch (position) {
        case 0:
            fragment = new HomeFragment();
            break;
        case 1:
            fragment = new ProfilFragment();
            break;
        case 2:
            fragment = new ProspekFragment();
            break;
        case 3:
            fragment = new AnnouncementFragment();
            break;
        case 4:
            Logout();
            break;
        default:
            break;
    }

    if (fragment != null) {
        android.app.FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.container, fragment).commit();

        // update selected item and title, then close the drawer
        mDrawerList.setItemChecked(position, true);
        mDrawerList.setSelection(position);
        setTitle(navMenuTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    } else {
        // error in creating fragment
        Log.e("SlidingMenu", "Error in creating fragment");
    }
}

インデックス2のナビゲーションドロワーメニュー項目を非表示にしたいです。どのようにそれを行うには？

UPDATE ナビゲーションドロワーに5つのメニュー項目がありますが、あるイベントが呼ばれたときにそのうちの1つを隠したいのです。

どのように解決するのですか？

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


private void hideItem()
   {
     navigationView = (NavigationView) findViewById(R.id.nav_view);
     Menu nav_Menu = navigationView.getMenu();
     nav_Menu.findItem(R.id.nav_settings).setVisible(false);
   }