相关疑难解决方法(0)

我写了一个在两个片段之间切换的虚拟活动.当您从FragmentA转到FragmentB时,FragmentA会被添加到后台堆栈中.但是,当我返回FragmentA(通过按回)时,会创建一个全新的FragmentA,并且它所处的状态将丢失.我感觉我跟这个问题一样,但我已经包含了一个完整的代码示例来帮助解决问题:

public class FooActivity extends Activity {
  @Override public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    final FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(android.R.id.content, new FragmentA());
    transaction.commit();
  }

  public void nextFragment() {
    final FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(android.R.id.content, new FragmentB());
    transaction.addToBackStack(null);
    transaction.commit();
  }

  public static class FragmentA extends Fragment {
    @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
      final View main = inflater.inflate(R.layout.main, container, false);
      main.findViewById(R.id.next_fragment_button).setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
          ((FooActivity) getActivity()).nextFragment();
        }
      });
      return main;
    } …