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我一起使用嵌套片段和viewPager。以下是HomeFragment的代码，它是viewPager中的片段之一。 HomeFragment包含另一个片段，称为FeedFragment，它只是一个RecyclerView。 FeedFragment内部我正在使用回调接口，通知HomeFragment已成功创建FeedFragment。我遇到的问题是，第一次创建HomeFragment，mListener值设置为HomeFragment的一个实例，位于onCreateView之内，并且所有内容都已正确加载。当我移动到viewPager不同的片段，并返回到HomeFragment，HomeFragmentonCreateView方法被调用，mListener再次设置为HomeFragment实例和onCreateView方法后，从FeedFragment调用，但mListener是null这个时候。Android ViewPager嵌套片段生命周期
以下是FeedFragment代码：继
public class FeedFragment extends Fragment {
RecyclerView feedRecyclerView;
FeedRecyclerViewAdapter feedRecyclerViewAdapter;
private OnCompleteListener mListener;
public FeedFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_feed, container, false);
feedRecyclerView = (RecyclerView) view.findViewById(R.id.postFeedItemContainer);
feedRecyclerViewAdapter = new FeedRecyclerViewAdapter(getActivity());
feedRecyclerView.setAdapter(feedRecyclerViewAdapter);
feedRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mListener.onComplete(feedRecyclerViewAdapter, this);
return view;
}
public interface OnCompleteListener {
void onComplete(
FeedRecyclerViewAdapter feedRecyclerViewAdapter, FeedFragment feedFragment);
}
public void setmListener(OnCompleteListener mListener) {
this.mListener = mListener;
}
}
为HomeFragment代码：
public class HomeFragment extends Fragment implements FeedFragment.OnCompleteListener {
// presenter instance
private HomeFragmentPresenter homeFragmentPresenter = HomeFragmentPresenter.getInstance();
public HomeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
FragmentTransaction fragmentTransaction = getChildFragmentManager().beginTransaction();
FeedFragment feedFragment = new FeedFragment();
feedFragment.setmListener(this);
fragmentTransaction.add(R.id.fragmentHomeFeedContainer, feedFragment);
fragmentTransaction.commit();
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_home, container, false);
}
@Override
public void onComplete(FeedRecyclerViewAdapter feedRecyclerViewAdapter, FeedFragment feedFragment) {
homeFragmentPresenter.fetchDataForAdapter(feedRecyclerViewAdapter, feedFragment);
}
}