我将 activity 转换为 Fragment Activity 但现在我无法添加操作栏

I convert activity to Fragment Activity but now I can not add Action bar

** 我想添加一个 Google 地图,所以我只是通过扩展 FragmentActivity 将我的普通 Activity class 转换为片段 activity 但是现在我无法添加一个应用程序栏(操作栏)来放置我的后退按钮以导航到上一个 activity **

public class LocationActivity extends FragmentActivity implements OnMapReadyCallback {
    public static final String EXTRA_DATA = "EXTRA_DATA";
    Item item;
    GoogleMap map;
    String title,address,info;
    Double lon,lat;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_location);


        //intialized map fragment
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.google_current_map);
        mapFragment.getMapAsync(this);

        //getData form serializable
        item = (Item) getIntent().getSerializableExtra(EXTRA_DATA);
        lat = Double.parseDouble(item.getLatitude());
        lon = Double.parseDouble(item.getLongitude());
        title = item.getTitle();
        address = item.getAddress();

        //add string together to show in map
        info = String.format("%s /n %s", title, address);

        FragmentTransaction mFragmentTransaction = getFragmentManager()
                .beginTransaction();
        mFragmentTransaction.addToBackStack(null);


    }

    // this event will enable the back
    // function to the button on press
    @Override
    public void onBackPressed() {
        if (getFragmentManager().getBackStackEntryCount() == 0) {
            this.finish();
        }
        else {
            getFragmentManager().popBackStack();
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        map = googleMap;
        LatLng Location = new LatLng(lat,lon);
        Toast.makeText(this, lat + " "+ lon, Toast.LENGTH_SHORT).show();
        map.addMarker(new MarkerOptions().position(Location).title(info));
        map.moveCamera(CameraUpdateFactory.newLatLng(Location));
    }
}

再次将Fragment转换为AppCompactActivity解决了。