title: FragmentTabHost - No tab known for tag null
body: <p>Few days ago I implemented <code>TabHostFramgent</code> in a <code>Fragment</code> with a <code>NavigationDrawer</code>, and I faced with a problem that is the following error : </p>
  
  <blockquote>
    <p>java.lang.IllegalStateException: No tab known for tag null</p>
  </blockquote>
  
  <p>The thing is that all works perfectly since my first item list of my <code>NavigationDrawer</code> is my <code>TabHostFragment</code>, so it works perfect, but the problem is when I go in example to the second item and then I want to go back to the first item, every time that I try so it crashes.</p>
  
  <p>I was searching everywhere, here in <code>SO</code>, <code>code.google.com</code>, etc... and I still don't get the proper answer.</p>
  
  <p>My <code>tab_host_test_2.xml</code>looks like : </p>
  
  <pre><code>  &lt;android.support.v4.app.FragmentTabHost xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:id="@android:id/tabhost"
      android:layout_width="match_parent"
      android:layout_height="match_parent" &gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:orientation="vertical" &gt;
  
          &lt;TabWidget
              android:id="@android:id/tabs"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="horizontal" /&gt;
  
          &lt;FrameLayout
              android:id="@android:id/tabcontent"
              android:layout_width="0dp"
              android:layout_height="0dp"
              android:layout_weight="0" /&gt;
  
          &lt;FrameLayout
              android:id="@+id/realtabcontent"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout_weight="1" /&gt;
      &lt;/LinearLayout&gt;
  
  &lt;/android.support.v4.app.FragmentTabHost&gt;
  </code></pre>
  
  <p>My <code>activity_main.xml</code> where I've got my <code>NavigationDrawer</code> looks like : </p>
  
  <pre><code> &lt;android.support.v4.widget.DrawerLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/drawer_layout"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;!-- Framelayout to display Fragments --&gt;
      &lt;FrameLayout
          android:id="@+id/frame_container"
          android:layout_width="match_parent"
          android:layout_height="match_parent" /&gt;
  
  
      &lt;!-- Listview to display slider menu --&gt;
      &lt;ListView
          android:id="@+id/list_slidermenu"
          android:layout_width="240dp"
          android:layout_height="match_parent"
          android:layout_gravity="start"
          android:choiceMode="singleChoice"
          android:divider="@color/list_divider"
          android:dividerHeight="1dp"
          android:listSelector="@drawable/list_selector"
          android:background="@color/list_background"/&gt;
  &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>
  
  <p>My <code>TabHostFragment.java</code>: </p>
  
  <pre><code>    public class TabHostFragment extends Fragment {
  
      public TabHostFragment(){
  
      }
      private FragmentTabHost mTabHost;
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container,
                               Bundle savedInstanceState) {
          View rootView = inflater.inflate(R.layout.tab_host_test2, container, false);
          return rootView;
      }
  
      @Override
      public void onViewCreated(View view, Bundle savedInstanceState) {
          mTabHost = (FragmentTabHost)view.findViewById(android.R.id.tabhost);
          mTabHost.setup(getActivity(), getChildFragmentManager(), R.id.realtabcontent);
  
          mTabHost.addTab(mTabHost.newTabSpec("tab1").setIndicator("Tab1"),
                  MisOfertasFragment.class, null);
          mTabHost.addTab(mTabHost.newTabSpec("tab2").setIndicator("Tab2"),
                  RecomendacionesFragment.class, null);
  
  
  
  
      }
  
  }
  </code></pre>
  
  <p>My <code>ActivityMain.java</code>:</p>
  
  <pre><code>public class MainActivity extends FragmentActivity {
      private DrawerLayout mDrawerLayout;
      private ListView mDrawerList;
      private ActionBarDrawerToggle mDrawerToggle;
      // saber si esta abierto
      public boolean mDrawerOpened;
      // nav drawer title
      private CharSequence mDrawerTitle;
      private FragmentTabHost mTabHost;
      // used to store app title
      private CharSequence mTitle;
  
      //para ponerlo visible
      public MenuItem mi;
  
      // slide menu items
      private String[] navMenuTitles;
      private TypedArray navMenuIcons;
  
      private ArrayList&lt;NavDrawerItem&gt; navDrawerItems;
      private NavDrawerListAdapter adapter;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
  
          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_layout);
          mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
  
          navDrawerItems = new ArrayList&lt;NavDrawerItem&gt;();
  
          // adding nav drawer items to array
          // Home
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
          // Find People
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
          // Photos
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
          // Communities, Will add a counter here
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
          // Pages
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
          // What's hot, We  will add a counter here
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));
          //AyudaSugerencias
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[6], navMenuIcons.getResourceId(6, -1)));
          navDrawerItems.add(new NavDrawerItem(navMenuTitles[7], navMenuIcons.getResourceId(7, -1)));
  
  
          // Recycle the typed array
          navMenuIcons.recycle();
  
          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
  
          getActionBar().setDisplayHomeAsUpEnabled(true);
          getActionBar().setBackgroundDrawable(new ColorDrawable(0xff1d97dd));
          getActionBar().setHomeButtonEnabled(true);
  
          mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                  R.drawable.ic_drawer, //nav menu toggle icon
                  R.string.app_name, // nav drawer open - description for accessibility
                  R.string.app_name // nav drawer close - description for accessibility
          ) {
              public void onDrawerClosed(View view) {
                  getActionBar().setTitle(
                          Html.fromHtml("&lt;font color='ffffff'&gt;"
                                  + mTitle + "&lt;/font&gt;"));
  
                  // calling onPrepareOptionsMenu() to show action bar icons
                  invalidateOptionsMenu();
                  mDrawerOpened = false;
                  syncState();
  
              }
  
              public void onDrawerOpened(View drawerView) {
                  getActionBar().setTitle(
                          Html.fromHtml("&lt;font color='ffffff'&gt;"
                                  + mDrawerTitle + "&lt;/font&gt;"));
  
                  // calling onPrepareOptionsMenu() to hide action bar icons
                  invalidateOptionsMenu();
                  mDrawerOpened = true;
                  syncState();
              }
          };
          mDrawerLayout.setDrawerListener(mDrawerToggle);
  
          if (savedInstanceState == null) {
              // on first time display view for first nav item
              displayView(0);
          }
      }
  
      /**
       * Slide menu item click listener
       */
      private class SlideMenuClickListener implements
              ListView.OnItemClickListener {
          @Override
          public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position,
                                  long id) {
              // display view for selected nav drawer item
              displayView(position);
          }
      }
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
  
  
          getMenuInflater().inflate(R.menu.main, menu);
  
  
          return true;
      }
  
      @Override
      public boolean onOptionsItemSelected(MenuItem item) {
          Fragment fragment = null;
          // toggle nav drawer on selecting action bar app icon/title
          if (mDrawerToggle.onOptionsItemSelected(item)) {
              return true;
          }
          // Handle action bar actions click
          switch (item.getItemId()) {
              case R.id.action_settings:
                  return true;
              case R.id.ofertasRefresh:
                  return true;
              case R.id.menu_search:
                  return true;
              case R.id.newOffer:
                  getFragmentManager().beginTransaction().replace(R.id.frame_container, new TipusNouProducte()).commit();
                  return true;
              default:
                  return super.onOptionsItemSelected(item);
          }
      }
  
      /* *
       * Called when invalidateOptionsMenu() is triggered
       */
      @Override
      public boolean onPrepareOptionsMenu(Menu menu) {
          // if nav drawer is opened, hide the action items
          boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
          menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
          if (mDrawerOpened) {
              menu.removeItem(R.id.ofertasRefresh);
              menu.removeItem(R.id.menu_search);
              menu.removeItem(R.id.newOffer);
          }
          if (!mDrawerOpened) {
              menu.add(Menu.NONE, R.id.ofertasRefresh, Menu.NONE, mTitle);
          }
          return super.onPrepareOptionsMenu(menu);
  
      }
  
      /**
       * Diplaying fragment view for selected nav drawer list item
       */
      private void displayView(int position) {
          mDrawerList.setItemChecked(position, true);
          mDrawerList.setSelection(position);
          setTitle(navMenuTitles[position]);
          mDrawerLayout.closeDrawer(mDrawerList);
          Fragment fragment = null;
  
          switch (position) {
              case 0:
                  fragment = new TabHostFragment();
                  break;
              case 1:
                  fragment = new RecomendacionesFragment();
                  break;
              case 2:
                  fragment = new LocalizacionFragment();
                  break;
              case 3:
                  fragment = new ListaProductosFragment();
                  break;
              case 4:
                  fragment = new ConfiguracionFragment();
                  break;
              case 5:
                  fragment = new AyudaSugerenciasFragment();
                  break;
              case 6:
                  fragment = new AyudaSugerencias();
                  break;
  
              default:
  
                  break;
          }
  
  
          if (fragment != null) {
              FragmentManager fragmentManager = getSupportFragmentManager();
              fragmentManager.beginTransaction()
                      .replace(R.id.frame_container, fragment).commit(); /// here says that replace android.app.Fragment in FragmentTransaction cannot be applied...
  
              // 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("MainActivity", "Error in creating fragment");
          }
      }
  
  
      @Override
      public void setTitle(CharSequence title) {
          mTitle = title;
          getActionBar().setTitle(mTitle);
  
      }
  
      /**
       * When using the ActionBarDrawerToggle, you must call it during
       * onPostCreate() and onConfigurationChanged()...
       */
  
      @Override
      protected void onPostCreate(Bundle savedInstanceState) {
          super.onPostCreate(savedInstanceState);
          // Sync the toggle state after onRestoreInstanceState has occurred.
          mDrawerToggle.syncState();
      }
  
      @Override
      public void onConfigurationChanged(Configuration newConfig) {
          super.onConfigurationChanged(newConfig);
          // Pass any configuration change to the drawer toggls
          mDrawerToggle.onConfigurationChanged(newConfig);
      }
  
  
  
  }
  </code></pre>
  
  <p>The full <code>LogCat</code> error is : </p>
  
  <pre><code>  03-04 16:53:05.708    2232-2232/info.androidhive.slidingmenu E/AndroidRuntime﹕ FATAL EXCEPTION: main
  Process: info.androidhive.slidingmenu, PID: 2232
  java.lang.IllegalStateException: No tab known for tag null
          at android.support.v4.app.FragmentTabHost.doTabChanged(FragmentTabHost.java:330)
          at android.support.v4.app.FragmentTabHost.onAttachedToWindow(FragmentTabHost.java:280)
          at android.view.View.dispatchAttachedToWindow(View.java:13406)
          at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2707)
          at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2714)
          at android.view.ViewGroup.addViewInner(ViewGroup.java:3919)
          at android.view.ViewGroup.addView(ViewGroup.java:3733)
          at android.view.ViewGroup.addView(ViewGroup.java:3678)
          at android.view.ViewGroup.addView(ViewGroup.java:3654)
          at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:958)
          at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
          at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
          at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
          at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:454)
          at android.os.Handler.handleCallback(Handler.java:739)
          at android.os.Handler.dispatchMessage(Handler.java:95)
          at android.os.Looper.loop(Looper.java:135)
          at android.app.ActivityThread.main(ActivityThread.java:5221)
          at java.lang.reflect.Method.invoke(Native Method)
          at java.lang.reflect.Method.invoke(Method.java:372)
          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
  </code></pre>
  
  <p><strong>EDIT</strong></p>
  
  <p>The answer of <a href="https://stackoverflow.com/a/28902823/4385913">@Y.S.</a>, was kinda different about what I was asking for, but it could be a solution, but it didn't worked fine at all, and the <code>NavigationDrawer</code> is under the <code>TabHostFragment</code>, etc... I don't want to change anything of my layout.</p>