Question

我有一个使用Firebase作为后端并在RecyclerView中显示数据的应用程序，发生的事情是，当我将数据保存到Firebase时，它没有在Recyclerview中以正确的方式显示数据，但某些数据为空，但是当我旋转屏幕时，所有数据都会显示https://bonsai.io/blog/efficient-sorting-of-geo-distances-in-elasticsearch

这是我的片段类

public class AddNewItemFragment extends Fragment {
public AddNewItemFragment() {

}
RecyclerView re;
FirebaseRecyclerAdapter<Note1, NoteHolder> adapter;
ProgressDialog pd;
String userid = "";
EditText textViewItemName;
EditText textViewItemPcs;
EditText textViewItemPssalePrice;
EditText textViewBoxCost;
DatabaseReference itemsDatabase;
FloatingActionButton fab;
Button itemSaveBtn;
private static final String KEY_ITEMNAME = "itemName";
private static final String KEY_ITEMSPCS = "itemPcs";
private static final String KEY_PSSALEPRICE = "itemPsSalePrice";
private static final String KEY_BOXCOST = "itemBoxCost";
private static final String KEY_ItemCat = "itemCat";
public View view;
String tabText;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.add_new_item_activity, container, false);
    //  if (getArguments() != null) {
    //      tabText = getArguments().getString("itemCat");
    //  } else {
    //      tabText = "CIGARETTE";
    //  }
    textViewItemName = view.findViewById(R.id.edittextItemsName);
    textViewItemPcs = view.findViewById(R.id.edittextItemsPcs);
    textViewItemPssalePrice = view.findViewById(R.id.edittextItemsPsSalePrice);
    textViewBoxCost = view.findViewById(R.id.edittextItemsBoxCost);

    re = view.findViewById(R.id.itemsListView);
    re.setLayoutManager(new LinearLayoutManager(getContext()));

    FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
    userid = user.getUid();
    itemsDatabase = FirebaseDatabase.getInstance().getReference().child("users").child(userid).child("items");
    fab = view.findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v) {
            saveNote();
        }
    });
    return view;
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
}
@Override
public void onStart() {
    super.onStart();
    FirebaseRecyclerOptions<Note1> options =
            new FirebaseRecyclerOptions.Builder<Note1>()
                    .setQuery(itemsDatabase, Note1.class)
                    .build();
    adapter = new FirebaseRecyclerAdapter<Note1, NoteHolder>(options) {
                @Override
                protected void onBindViewHolder(@NonNull final NoteHolder holder, final int position, @NonNull final Note1 model) {
                    String ItemsID = getRef(position).getKey();
                    if (ItemsID != null) {
                        itemsDatabase.child(ItemsID).addValueEventListener(new ValueEventListener() {
                            @Override
                            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                                if (dataSnapshot.exists()) {
                                    String itemName = (dataSnapshot.child("itemName").getValue()).toString();
                                    String itemPcs = (dataSnapshot.child("itemPcs").getValue()).toString();
                                    String itemPsSalePrice = (dataSnapshot.child("itemPsSalePrice").getValue()).toString();
                                    String boxCost = (dataSnapshot.child("itemBoxCost").getValue()).toString();
                                    holder.textViewItemName.setText(itemName);
                                    holder.textViewItemPcs.setText(itemPcs);
                                    holder.textViewItemPssalePrice.setText(itemPsSalePrice);
                                    holder.textViewBoxCost.setText(boxCost);
                                }
                            }

                            @Override
                            public void onCancelled(@NonNull DatabaseError databaseError) {
                            }
                        });
                    }
                }

                @NonNull
                @Override
                public NoteHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.add_item_design_adapter, parent, false);
                    return new NoteHolder(v);
                }
            };
    re.setAdapter(adapter);
    adapter.startListening();
}


private void setProgressStatus() {
    pd = new ProgressDialog(getActivity());

    // Set progress dialog style spinner
    pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);

    // Set the progress dialog title and message
    pd.setTitle("Please Wait Feras!!!!!.");
    pd.setMessage("Loading.........");

    // Set the progress dialog background color
    Objects.requireNonNull(pd.getWindow()).setBackgroundDrawable(new ColorDrawable(Color.WHITE));

    pd.setCancelable(false);

    // Finally, show the progress dialog
    pd.show();


}

private void saveNote() {
    itemsDatabase = FirebaseDatabase.getInstance().getReference();
    String itemName = textViewItemName.getText().toString();
    String itemPcs = textViewItemPcs.getText().toString();
    String itemPsSalePrice = textViewItemPssalePrice.getText().toString();
    String itemBoxCost = textViewBoxCost.getText().toString();


    if (itemName.trim().isEmpty() || itemPcs.trim().isEmpty() ||
            itemPsSalePrice.trim().isEmpty() || itemBoxCost.trim().isEmpty()) {
        Toast.makeText(getActivity(), "Please enter all information", Toast.LENGTH_SHORT).show();
        return;
    }

    Map<String, Object> note = new HashMap<>();
    note.put(KEY_ITEMNAME, itemName);
    note.put(KEY_ITEMSPCS, itemPcs);
    note.put(KEY_PSSALEPRICE, itemPsSalePrice);
    note.put(KEY_BOXCOST, itemBoxCost);

    FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
    if (user != null) {
        userid = user.getUid();
    }
    String key = itemsDatabase.push().getKey();
    itemsDatabase.child("users").child(userid).child("items").child(key).setValue(note);

}

public static class NoteHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    private OnItemClickListener mListener;
    TextView textViewItemName;
    TextView textViewItemPcs;
    TextView textViewItemPssalePrice;
    TextView textViewBoxCost;


    NoteHolder(View itemView) {
        super(itemView);
        textViewItemName = itemView.findViewById(R.id.itemName);
        textViewItemPcs = itemView.findViewById(R.id.itemPcs);
        textViewItemPssalePrice = itemView.findViewById(R.id.itemPs);
        textViewBoxCost = itemView.findViewById(R.id.itemBoxCost);
        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (mListener != null) {
            int position = getAdapterPosition();
            if (position != RecyclerView.NO_POSITION) {
                mListener.onItemClick(position);
            }
        }
    }

    public interface OnItemClickListener {
        void onItemClick(int position);

        void onShowItemClick(int position);

        void onDeleteItemClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener listener) {
        mListener = listener;
    }
}

Answer 1

我猜您的代码正在尝试在写入数据之前读取数据。这是因为您正在使用push()创建密钥，然后写入数据。但是创建密钥时会触发ValueEventListener。但是没有数据。当您旋转设备时，代码会再次运行。但是这次写操作完成了。尝试使用OnSuccessListener检查写入是否完成，然后刷新数据。

RecyclerView在从Firebase到片段中检索数据时不稳定

1 个答案: