Firebase RecyclerView 适配器未获得准确的视图位置

Question

我正在使用 Firebase UI 并且遇到了一个独特的问题。当我加载 RecyclerView 时，没有任何问题。我单击 RecyclerView 上的一个项目并获取被单击项目的 .push() 值。然后它从存储在 Firebase 数据库中的 Firebase .push() 值中获取数据，并将其发送到另一个 activity。见下图：

第二张图片是通过 Intent 接收数据的 activity。当我点击回到 RecyclerView 时，我再次点击“8”，我正在加载一个不同的数字（现在它看起来是 1）。

最后，我担心我没有正确设置 RecyclerView。这是我的代码：

创建轮询对象 (POJO) 并写入 Firebase：

        mSubmitPollCreation.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            //TODO: Need to check if poll requirements are added, i.e. Question, Answer, ......
            //check if image has been loaded first
            if (resultImageURL == null) {
                Toast.makeText(getApplicationContext(), getResources().getString(R.string.no_image_selected), Toast.LENGTH_LONG).show();
                return;
            }

            //capture answers
            if (mNumberOfPollAnswersCreatedByUser > 5) {
                Toast.makeText(getApplicationContext(), getResources().getText(R.string.poll_answers_greater_than_five), Toast.LENGTH_LONG).show();
                mNumberOfPollAnswersCreatedByUser = 5;
            }
            for (int i = 0; i < mNumberOfPollAnswersCreatedByUser; i++) {
                EditText editText = (EditText) mEditTextAnswerLayout.findViewWithTag(getResources().getString(R.string.created_answer_editText_id) + String.valueOf(i + 1));
                String editTextInputForAnswer = String.valueOf(editText.getText());
                mPollAnswers.add(0, editTextInputForAnswer);                 Toast.makeText(getApplicationContext(),editTextInputForAnswer,Toast.LENGTH_SHORT).show();
            }


            Poll poll = new Poll(mCreatePollQuestion.getText().toString(), resultImageURL, mPollAnswers);
            Map<String, Object> pollMap = poll.toMap();
            final String key = mBaseRef.child("Polls").push().getKey();
            Map<String, Object> childUpdates = new HashMap<String, Object>();
            childUpdates.put("/Polls/" + key, pollMap);

            mBaseRef.updateChildren(childUpdates);
            Collections.reverse(mPollAnswers);
            for (int i = 0; i < mPollAnswers.size(); i++) {
                mBaseRef.child("Polls").child(key).child("answers").child(String.valueOf(i + 1)).updateChildren(poll.answerConvert(mPollAnswers, i));
            }

            Intent toHomeActivity = new Intent(CreateActivity.this, HomeActivity.class);
            toHomeActivity.putExtra("viewpager_position", 2);
            startActivity(toHomeActivity);
        }
    });

我从 Firebase 读取并填充 RecyclerView 的位置：

public class LiveFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. 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 FloatingActionButton mFloatingActionAdd;

private FirebaseRecyclerAdapter<Poll, PollHolder> mFireAdapter;

private RecyclerView.ItemAnimator mItemAnimator;


// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

public LiveFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment LiveFragment.
 */
// 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");

    mRecyclerview = (RecyclerView) v.findViewById(R.id.list);
    mRecyclerview.setItemAnimator(new SlideInLeftAnimator());


    mLayoutManager = new LinearLayoutManager(getContext());
    mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    mLayoutManager.setReverseLayout(true);
    mLayoutManager.setStackFromEnd(true);

    mFloatingActionAdd = (FloatingActionButton) getActivity().findViewById(R.id.myFAB);
    mFloatingActionAdd.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent I = new Intent(getActivity().getApplicationContext(), CreateActivity.class);
            startActivity(I);
        }
    });


    mRecyclerview.setLayoutManager(mLayoutManager);
    return v;
}

// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
    scrollToPosition();
}

@Override
public void onStart() {
    super.onStart();

    mFireAdapter = new FirebaseRecyclerAdapter<Poll, PollHolder>(Poll.class, R.layout.latest_item, PollHolder.class, mBaseRef.child("Polls")) {
        @Override
        protected void populateViewHolder(PollHolder viewHolder, final Poll model, final int position) {
            viewHolder.mPollQuestion.setText(model.getQuestion());
            Picasso.with(getActivity().getApplicationContext())
                    .load(model.getImage_URL())
                    .fit()
                    .into(viewHolder.mPollImage);
            viewHolder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Log.v("TAG", model.toString());
                    Log.v("TAG","ONCLICKED");
                    Intent toPoll = new Intent(getActivity(), PollHostActivity.class);
                    toPoll.putExtra("POLL_ID", mFireAdapter.getRef(position).getKey());
                    startActivity(toPoll);

                }
            });
            Log.v("TAG", mFireAdapter.getRef(position).getKey());
            Log.v("TAG", String.valueOf(position));
            Log.v("TAG", model.getQuestion());
            Log.v("TAG", model.getImage_URL());
        }
    };

    mRecyclerview.setAdapter(mFireAdapter);
    scrollToPosition();



}

@Override
public void onStop() {
    super.onStop();
    if (mFireAdapter != null) {
        mFireAdapter.cleanup();
    }
}


@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}


public static class PollHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    TextView mPollQuestion;
    ImageView mPollImage;
    View mView;


    public PollHolder(View itemView) {
        super(itemView);

        mPollQuestion = (TextView) itemView.findViewById(R.id.latest_item_question);
        mPollImage = (ImageView) itemView.findViewById(R.id.pollThumbNailImage);
        this.mView = itemView;
        itemView.setOnClickListener(this);

    }

    @Override
    public void onClick(View view) {
        Log.v("TAG", "CLICKED");
    }
}


private void scrollToPosition(){
    mFireAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
        @Override
        public void onItemRangeInserted(int positionStart, int itemCount) {
            super.onItemRangeInserted(positionStart, itemCount);
            int pollCount = mFireAdapter.getItemCount();
            int lastVisiblePosition = mLayoutManager.findLastCompletelyVisibleItemPosition();

            // If the recycler view is initially being loaded or the user is at the bottom of the list, scroll
            // to the bottom of the list to show the newly added message.
            if (lastVisiblePosition == -1 ||
                    (positionStart >= (pollCount - 1) && lastVisiblePosition == (positionStart - 1))) {
                mRecyclerview.scrollToPosition(positionStart);
            }
        }
    });
   }
}

我的想法：

我在正确的位置调用 mFireAdapter.cleanup() 吗？
单击“8”并看到“1”的问题不会出现在第一次加载 RecyclerView 时，它只会在我从 activity（第二张图片）开始时出现然后导航回 RecyclerView。
我调用 .setStackFromEnd(true) 和 .setReverseLayout(true) 来反转存储在 FirebaseDatabase 中的数据，这可能是导致问题的原因。
我在 .populateViewHolder() 方法中设置了 .setOnClickListener()，并使用以下内容将 .push() 键传递给下一个 activity：
```
  toPoll.putExtra("POLL_ID", mFireAdapter.getRef(position).getKey());
```

此方法获取的密钥可能不正确。

最后，Firebase 数据库：

如有任何帮助，我们将不胜感激！

Answer 1

您不应在 populateViewHolder 之外使用 position，因为它的值可能不同。相反，让你的 viewHolder 最终并使用 viewHolder.getAdapterPosition() 来替换它。

Firebase RecyclerView 适配器未获得准确的视图位置

Firebase RecylcerView Adapter Not Getting Accurate View Position

java

android

firebase

firebase-realtime-database

firebaseui