"No such method error" bei der Verwendung von android.Unterstützung.v4.app.FragmentActivity.getActionBar

Ich versuche die navigation Schublade im Lebkuchen alles gut funktioniert.Wenn ich auf navigation-Menü, erhalte ich diese exception.Hinzugefügt habe ich alles Bibliothek,Thema,Fach-Liste. Eigentlich brauche ich getsupportActionBar() im fragment, so wie ich es bekommen kann bitte helft mir.

code:

public class RiverFragment extends Fragment{


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

        //Retrieving the currently selected item number
        int position = getArguments().getInt("position");

        //List of rivers
        String[] rivers = getResources().getStringArray(R.array.rivers);

        //Creating view correspoding to the fragment
        View v = inflater.inflate(R.layout.fragment_layout, container, false);

        //Getting reference to the TextView of the Fragment
        TextView tv = (TextView) v.findViewById(R.id.tv_content);

        //Setting currently selected river name in the TextView
        tv.setText(rivers[position]);       

        //Updating the action bar title
        getActivity().getActionBar().setTitle(rivers[position]);


        return v;
    }
}

Ausnahme:

01-04 11:47:21.601: E/AndroidRuntime(20537): FATAL EXCEPTION: main
01-04 11:47:21.601: E/AndroidRuntime(20537): java.lang.NoSuchMethodError: android.support.v4.app.FragmentActivity.getActionBar
01-04 11:47:21.601: E/AndroidRuntime(20537):    at in.wptrafficanalyzer.navigationdrawerdemo.RiverFragment.onCreateView(RiverFragment.java:36)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.os.Handler.handleCallback(Handler.java:587)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.os.Handler.dispatchMessage(Handler.java:92)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.os.Looper.loop(Looper.java:130)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at android.app.ActivityThread.main(ActivityThread.java:3687)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at java.lang.reflect.Method.invokeNative(Native Method)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at java.lang.reflect.Method.invoke(Method.java:507)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
01-04 11:47:21.601: E/AndroidRuntime(20537):    at dalvik.system.NativeStart.main(Native Method)