菜单未显示在活动中

我正在做一个项目，我的代码看起来还不错，但是在其中一个活动中，我能够在屏幕上看到菜单选项，而在另一个活动中，我看不到菜单选项。

未显示菜单选项的活动的代码为：

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;


public class DetailActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_detail);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment())
                .commit();
    }
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        startActivity(new Intent(this, SettingsActivity.class));
        return true;
    }

    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

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

        View rootView = inflater.inflate(R.layout.fragment_detail, container, false);
        Intent intent = getActivity().getIntent();
        if (intent != null && intent.hasExtra(Intent.EXTRA_TEXT)) {
            String forecastStr = intent.getStringExtra(Intent.EXTRA_TEXT);
            ((TextView) rootView.findViewById(R.id.detail_text))
                    .setText(forecastStr);
        }
        return rootView;
    }
}

}

同样，此活动的菜单xml文件也可以。问题与Android的任何版本有关吗？