问MapFragment不会自动绘制

EN

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    AdView av = (AdView) findViewById(R.id.top_banner_ad_MM); // Set the banner ad view
    AdRequest ar = new AdRequest.Builder()
            .addTestDevice("106E258A55DADC2A54C47969C87A91AC")
            .build();
    av.loadAd(ar);
    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();

// Make the new map fragment (MapFragment = google's class)
MapFragment mf = MapFragment.newInstance();
ft.add(R.id.mapview_frame, mf, "map");
ft.commit();

mf.getMapAsync(new OnMapReadyCallback()
{
    @Override
    public void onMapReady(GoogleMap googleMap)
    {

        gMap = googleMap; // Use the googleMap reference in this class

        MapFragment mf = (MapFragment) getFragmentManager().findFragmentByTag("map");
        ViewGroup.LayoutParams lp = mf.getView().getLayoutParams();
        lp.height = (findViewById(R.id.mapview_frame)).getHeight();
        lp.width = (findViewById(R.id.mapview_frame)).getWidth();
        mf.getView().setLayoutParams(lp);

        // Set camera position to Ein Gedi 3, Holon
        CameraPosition cp = new CameraPosition.Builder()
                .target(addr)
                .zoom(9) // Set zoom level to be able to see Tel Aviv
                .bearing(0) // Set bearing to North
                .build(); // Build
        gMap.animateCamera(CameraUpdateFactory.newCameraPosition(cp)); // Apply position

        getFragmentManager().findFragmentByTag("map").getView().invalidate();
        Log.w("GETEVENT-MAPINIT", "I just finished the fucking map initialization");
    }
});