使用FragmentTabHost时发生ClassCastException

Question

I am using FragmentTabHost with android support library,

My layout file sub_main.xml :

<android.support.v4.app.FragmentTabHost 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

   <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >

        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:orientation="horizontal" />

        <FrameLayout
            android:id="@+id/tabFrameLayout"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="1" />
    </LinearLayout>

</android.support.v4.app.FragmentTabHost>

The above layout is used in my fragment:

   public class MyFragment extends Fragment{
       ...
       private FragmentTabHost mTabHost;
       private View content;

      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            super.onCreateView(inflater, container, savedInstanceState);

            View content = inflater.inflate(R.layout.sub_main, null); 

            // the following code throw ClassCastException, why?
            mTabHost = (FragmentTabHost) content.findViewById(android.R.id.tabhost);

            return content;
        }
   ...
}

But, I got the ClassCastException exception in the above code where mTabHost is initialized in onCreateView() :

07-03 16:35:09.704: E/AndroidRuntime(25350): java.lang.ClassCastException: android.widget.TabHost cannot be cast to android.support.v4.app.FragmentTabHost

It complains that TabHost can not be cast to FragmentTabHost , why & how to get rid of it. Thanks.

Answer 1

mTabHost = (FragmentTabHost) content.findViewById(android.R.id.tabhost);

should be

mTabHost = (FragmentTabHost) content.findViewById(R.id.tabhost);

and in the xml layout you should specify

android:id="@android:id/tabhost"

as

android:id="@+id/tabhost"