Bem, quando eu estou trabalhando em algo e eu preciso configurar a barra de ação no meu aplicativo eu comecei a partir dohttp://developer.android.com e eu encontrei o que estou procurando

public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
    NavUtils.navigateUpFromSameTask(this);
    return true;
}
return super.onOptionsItemSelected(item);}

é claro depois de adicionar o

<activity
    android:name="com.example.myfirstapp.DisplayMessageActivity"
    android:label="@string/title_activity_display_message"
    android:parentActivityName="com.example.myfirstapp.MainActivity" >
    <!-- Parent activity meta-data to support 4.0 and lower -->
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.example.myfirstapp.MainActivity" />
</activity>

e a

@Override
public void onCreate(Bundle savedInstanceState) {
    ...
    getActionBar().setDisplayHomeAsUpEnabled(true);
}

Eu fiz tudo isso, mas quando no meu programa eu pressione o botão para cima na barra de ação o programa trava e aqui está o logcat

09-04 12:54:02.087: E/AndroidRuntime(11033): FATAL EXCEPTION: main
09-04 12:54:02.087: E/AndroidRuntime(11033): java.lang.IllegalArgumentException: Activity LegendActivity does not have a parent activity name specified. (Did you forget to add the android.support.PARENT_ACTIVITY <meta-data>  element in your manifest?)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.support.v4.app.NavUtils.navigateUpFromSameTask(NavUtils.java:177)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at com.yay.android.projects.stories.LegendActivity.onOptionsItemSelected(LegendActivity.java:44)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.app.Activity.onMenuItemSelected(Activity.java:2611)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at com.android.internal.widget.ActionBarView$3.onClick(ActionBarView.java:206)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.view.View.performClick(View.java:4261)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.view.View$PerformClick.run(View.java:17356)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.os.Handler.handleCallback(Handler.java:615)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.os.Handler.dispatchMessage(Handler.java:92)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.os.Looper.loop(Looper.java:137)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at android.app.ActivityThread.main(ActivityThread.java:4921)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at java.lang.reflect.Method.invokeNative(Native Method)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at java.lang.reflect.Method.invoke(Method.java:511)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
09-04 12:54:02.087: E/AndroidRuntime(11033):    at dalvik.system.NativeStart.main(Native Method)

tudo é apenas como eles disseram ofcourse eu mudei os nomes de atividade correspondentes aos nomes que eu tenho qual é o problema aqui?