片段中的RecyclerView – 没有连接适配器，跳过布局

我有一个奇怪的情况，我有一个托管TabLayout/Viewpager的Activity ，它根据对Firebase数据库的更改来填充数据。 不幸的是， RecyclerView没有被填充，我在logcat中收到以下错误。 我相信即使片段不在屏幕上也会加载片段，这会导致RecyclerView的填充错误。 当旋转屏幕时， RecyclerView会填充，这也很奇怪：

 12-13 21:31:40.013 12490-12490/com.troychuinard.fanpolls E/RecyclerView: No adapter attached; skipping layout 

这是我在主机Activity的ViewPager适配器：

 public class SectionPagerAdapter extends FragmentPagerAdapter { public SectionPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { switch (position) { case 0: return new TrendingFragment(); case 1: return new FollowingFragment(); case 2: return new LiveFragment(); default: return new TrendingFragment(); } } @Override public int getCount() { return 3; } @Override public CharSequence getPageTitle(int position) { switch (position) { case 0: return getResources().getString(R.string.trending_text); case 1: return getResources().getString(R.string.following_text); case 2: return getResources().getString(R.string.new_text); default: return getResources().getString(R.string.trending_text); } } } 

这是完整的片段，我在LiveFragment onCreateView()函数中初始化RecyclerView ，这是LiveFragment中的选项卡3：

 public class LiveFragment extends Fragment { // TODO: Rename parameter arguments, choose names that match // the fragment initialization parameters, eg ARG_ITEM_NUMBER private static final String ARG_PARAM1 = "param1"; private static final String ARG_PARAM2 = "param2"; private RecyclerView mRecyclerview; private DatabaseReference mBaseRef; private DatabaseReference mPollsRef; private LinearLayoutManager mLayoutManager; private FirebaseRecyclerAdapter  mFireAdapter; // TODO: Rename and change types of parameters private String mParam1; private String mParam2; private OnFragmentInteractionListener mListener; public LiveFragment() { // Required empty public constructor } /https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/*https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* Use this factory method to create a new instance of https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* this fragment using the provided parameters. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* @param param1 Parameter 1. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* @param param2 Parameter 2. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* @return A new instance of fragment LiveFragment. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/*/ // TODO: Rename and change types and number of parameters public static LiveFragment newInstance(String param1, String param2) { LiveFragment fragment = new LiveFragment(); Bundle args = new Bundle(); args.putString(ARG_PARAM1, param1); args.putString(ARG_PARAM2, param2); fragment.setArguments(args); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mBaseRef = FirebaseDatabase.getInstance().getReference(); mPollsRef = mBaseRef.child("Polls"); if (getArguments() != null) { mParam1 = getArguments().getString(ARG_PARAM1); mParam2 = getArguments().getString(ARG_PARAM2); } } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment final View v = inflater.inflate(R.layout.fragment_new, container, false); Log.v("TAG", "ON CREATE CALLED FROM NEW"); mLayoutManager = new LinearLayoutManager(getActivity()); mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL); mRecyclerview = (RecyclerView)v.findViewById(R.id.new_RecyclerView); if (mRecyclerview != null){ mRecyclerview.setHasFixedSize(true); } if (mRecyclerview == null){ Log.v("TAG", "RECYCLERVIEW NULL"); } else if (mLayoutManager == null){ Log.v("TAG", "LAYOUTMANAGER NULL"); } else if (mFireAdapter == null) { Log.v("TAG", "mFIREADAPTER NULL"); } return v; } // TODO: Rename method, update argument and hook method into UI event public void onButtonPressed(Uri uri) { if (mListener != null) { mListener.onFragmentInteraction(uri); } } @Override public void onStart() { super.onStart(); } @Override public void onStop() { super.onStop(); if (mFireAdapter != null){ mFireAdapter.cleanup(); } } @Override public void onActivityCreated(@Nullable Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); mRecyclerview.setLayoutManager(mLayoutManager); mFireAdapter = new FirebaseRecyclerAdapter(Poll.class, R.layout.latest_item, PollHolder.class, mPollsRef) { @Override protected void populateViewHolder(PollHolder viewHolder, Poll model, int position) { viewHolder.mPollQuestion.setText(model.getQuestion()); Picasso.with(getActivity().getApplicationContext()) .load(model.getImage_URL()) .fit() .into(viewHolder.mPollImage); Log.v("QUESTION", model.getQuestion()); Log.v("IMAGE", model.getImage_URL()); } }; mRecyclerview.setAdapter(mFireAdapter); mPollsRef.addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot x : dataSnapshot.getChildren()){ mFireAdapter.notifyItemInserted(0); } } @Override public void onCancelled(DatabaseError databaseError) { } }); } @Override public void onAttach(Context context) { super.onAttach(context); if (context instanceof OnFragmentInteractionListener) { mListener = (OnFragmentInteractionListener) context; } else { throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener"); } } @Override public void onDetach() { super.onDetach(); mListener = null; } public static class PollHolder extends RecyclerView.ViewHolder { TextView mPollQuestion; ImageView mPollImage; public PollHolder(View itemView) { super(itemView); mPollQuestion = (TextView) itemView.findViewById(R.id.latest_item_question); mPollImage = (ImageView) itemView.findViewById(R.id.pollThumbNailImage); } } /https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/*https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* This interface must be implemented by activities that contain this https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* fragment to allow an interaction in this fragment to be communicated https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* to the activity and potentially other fragments contained in that https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* activity. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* 
 https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/* See the Android Training lesson Communicating with Other Fragments for more information. https://stackoverflow.com/questions/41134470/recyclerview-in-fragment-no-adapter-attached-skipping-layout/*/ public interface OnFragmentInteractionListener { // TODO: Update argument type and name void onFragmentInteraction(Uri uri); } } 

Answer 1

从firebase读取数据后，将适配器从onCreateView移动到onActivityCreated方法。

 @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); //read Poll data from firebase mPollsRef for example //.... database reference to firebase //Query mPollsRef = databaseReference.child("pools").limitToFirst(200); mRecyclerview.setLayoutManager(mLayoutManager); mFireAdapter = new FirebaseRecyclerAdapter(Poll.class, R.layout.latest_item, PollHolder.class, mPollsRef) { @Override protected void populateViewHolder(PollHolder viewHolder, Poll model, int position) { viewHolder.mPollQuestion.setText(model.getQuestion()); Picasso.with(getActivity().getApplicationContext()) .load(model.getImage_URL()) .fit() .into(viewHolder.mPollImage); Log.v("QUESTION", model.getQuestion()); Log.v("IMAGE", model.getImage_URL()); } }; mRecyclerview.setAdapter(mFireAdapter); } 

我在HostActivity.java初始化Pager的代码

 private FragmentPagerAdapter mPagerAdapter; private ViewPager mViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_absence); // Create the adapter that will return a fragment for each section mPagerAdapter = new FragmentPagerAdapter(getSupportFragmentManager()) { private final Fragment[] mFragments = new Fragment[] { new MyAbsenceFragment(), new MyAttendanceFragment(), new AbsTypesFragment(), new LiveFragment(), }; private final String[] mFragmentNames = new String[] { "Absences", "Attendances", "AbsTypes", "Live" }; @Override public Fragment getItem(int position) { return mFragments[position]; } @Override public int getCount() { return mFragments.length; } @Override public CharSequence getPageTitle(int position) { return mFragmentNames[position]; } }; // Set up the ViewPager with the sections adapter. mViewPager = (ViewPager) findViewById(R.id.container); mViewPager.setAdapter(mPagerAdapter);