Android BackStack 问题

Question

我无法解决 BackStack 的问题。我有 3 个由 Activity 管理的 fragment :

我使用这段代码的 fragment 之间的导航:

private void showFragment(BabysitFragment babysitFragment, UserRequest userRequest) {
   FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
   switch (babysitFragment) {
      case CHILDREN_OVERVIEW:
        toolbar.setVisibility(View.VISIBLE);
        Fragment childrenSpecification = ChildrenOverviewFragment.newInstance(userRequest);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.replace(R.id.fragment_container, childrenSpecification, BabysitFragment.CHILDREN_OVERVIEW.getSimpleName()).commit();
        break;
      case CHILD_SPECIFICATION:
        toolbar.setVisibility(View.VISIBLE);
        Fragment childSpecification = ChildSpecificationFragment.newInstance(userRequest);
        fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.replace(R.id.fragment_container, childSpecification, BabysitFragment.CHILD_SPECIFICATION.getSimpleName()).commit();
        break;
   }
}

//Gets called by FinalizeFrag and ChildSpecificationFrag
@Override
public void onChildrenOverviewNeeded(UserRequest userRequest) {
    showFragment(BabysitFragment.CHILDREN_OVERVIEW, userRequest);
}

//Gets called by ChildrenOverviewFrag
@Override
public void onChildSpecificationNeeded(UserRequest userRequest) {
    showFragment(BabysitFragment.CHILD_SPECIFICATION, userRequest);
}

我希望用户能够使用其他 2 个 fragment 的后退按钮返回到 FinalizeFrag。这适用于当前代码，但在 1 个流程中我确实遇到了问题:

1. 用户将新的“Child”保存在 ChildSpecificationFrag 中(工具栏中的保存图标)
2. 用户被重定向到 ChildrenOverviewFrag
3. 用户按下后退按钮
4. 停留在 ChildrenOverviewFrag(应该重定向到 FinalizeFrag)

注意:当我再次按下按钮时，它会重定向到 FinalizeFrag

点击关闭按钮时的代码(ChildSpecificationFragment):

if (id == android.R.id.home) {
  getActivity().onBackPressed();
}

点击保存按钮时的代码(ChildSpecificationFragment):

...
userRequest.getFamilyDetails().getChildren().add(child);
getActivity().getSupportFragmentManager().popBackStackImmediate();
onChildrenOverviewNeededListener.onChildrenOverviewNeeded(userRequest, this);

如您所见，我正在从 BackStack 中删除 fragment 。我究竟做错了什么？提前致谢!

Answer 1

在执行“用户被重定向到 ChildrenOverviewFrag”之前，不要调用 addToBackStack，