getSupportFragmentManager returns null
问题 I'd like to show Google maps in my android app: public class DisplayMapActivity extends ActionBarActivity { private LbsTracker2 lbsTracker2; private GoogleMap googleMap; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); try { this.initilizeMap(); } catch (Exception e) { e.printStackTrace(); } } @Override protected void onResume() { super.onResume(); initilizeMap(); } private void initilizeMap() { if