Android - Top Back Button not working

I have this button on the topmost left part. And for some reason it is not going back to it's previous page when I click it. I've checked the other links already but it is not working.

The activity code on that one

public class CardListActivity extends Activity  {
    private static final String LOG_TAG = CardListActivity.class.getSimpleName();
    private EventBus eventBus;
    private Activity activity;
    private CardListRequest cardListRequest;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    init();

}

public void init() {
    Log.e(LOG_TAG, "XXXX Start : init XXXX");
    setUpActionBar();
    activity = this;
    setContentView(R.layout.activity_card_list);


    Log.e(LOG_TAG, "XXXX Finish : init XXXX");
}

private void setUpActionBar() {
    getActionBar().setTitle(CardListActivity.class.getSimpleName());
    getActionBar().setDisplayHomeAsUpEnabled(true);
}


}

AndroidManifest.xml

...

    <activity
        android:name=".CardListActivity"
        android:label="@string/title_activity_card_list"
        android:parentActivityName=".HomeActivity2">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.pw.mccdealsapp.HomeActivity2" />
    </activity>

...

This page contains all the information to create an Up button that works correctly.

You need to add, in your activity, something like:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            NavUtils.navigateUpFromSameTask(this);
            return true;
     }
     return super.onOptionsItemSelected(item);
}