问题记录-Fragment导包不同导致无法自动转型

 1 public class MainActivity extends FragmentActivity {
 2 
 3     @Override
 4     public void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.activity_main);
 7         FragmentManager fm=getSupportFragmentManager();
 8         Fragment fragment= fm.findFragmentById(R.id.fragmentContainer);
 9         if (fragment == null) {
10             fragment=new CrimeFragment();
11             fm.beginTransaction()
12                     .add(R.id.fragmentContainer, fragment)
13                     .commit();
14         }
15     }
16 }