public class MainActivity extends FragmentActivity {

     @Override

     public void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         FragmentManager fm=getSupportFragmentManager();

         Fragment fragment= fm.findFragmentById(R.id.fragmentContainer);

         if (fragment == null) {

             fragment=new CrimeFragment();

             fm.beginTransaction()

                     .add(R.id.fragmentContainer, fragment)

                     .commit();

         }

     }

 }