Question

我编写了一个记事应用程序。在这里，您可以查看笔记，对其进行编辑并通过滑动将其删除。启动应用程序时，一切正常，直到我添加新笔记。创建新笔记并返回MainActivity后，recyclerview中的项目将不可见。然后，我必须在recyclerview上滚动，以使这些项目再次可见。从现在开始，即使删除一个项目也会导致不可见的项目。 Here是一个视频（添加新笔记后会录制该视频-删除项目后将不可见，您必须在recyclerview上滚动才能将其取回）。奇怪的是，在我创建新笔记之前，一切正常。那么我的firestorelistener或ArrayList可能有问题吗？

主要活动代码：

public class MainActivity extends AppCompatActivity implements RecyclerItemTouchHelper.RecyclerItemTouchHelperListener {

private FirebaseFirestore db;

private RecyclerView recyclerView;
private RecyclerView.LayoutManager recyclerViewLayoutManager;
private FirestoreRecyclerAdapter adapter;
private List<Note> notesList;

private ListenerRegistration firestoreListener;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    recyclerView = findViewById(R.id.rvNoteList);
    db = FirebaseFirestore.getInstance();

    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    recyclerView.addItemDecoration(new com.raycroud.notes.notes.utils.DividerItemDecoration(MainActivity.this, LinearLayoutManager.VERTICAL, 16));
    recyclerView.setAdapter(adapter);

    ItemTouchHelper.SimpleCallback itemTouchHelperCallback = new RecyclerItemTouchHelper(0, ItemTouchHelper.LEFT, MainActivity.this);
    new ItemTouchHelper(itemTouchHelperCallback).attachToRecyclerView(recyclerView);

    loadNotesList();

    notesList = new ArrayList<>();

    firestoreListener = db.collection("users").document(firebase_user_uid).collection("notes")
            .addSnapshotListener(new EventListener<QuerySnapshot>() {
                @Override
                public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {
                    if (e != null) {
                        Log.e("LOL", "Listen failed!", e);
                        return;
                    }

                    notesList.clear();

                    for (DocumentSnapshot doc : documentSnapshots) {
                        Note note = doc.toObject(Note.class);
                        note.setId(doc.getId());
                        notesList.add(note);
                    }

                    adapter.notifyDataSetChanged();
                }
            });
}

private void loadNotesList() {

    Query query = db.collection("users").document(firebase_user_uid).collection("notes");

    FirestoreRecyclerOptions<Note> response = new FirestoreRecyclerOptions.Builder<Note>()
            .setQuery(query, Note.class)
            .build();

    adapter = new FirestoreRecyclerAdapter<Note, NoteViewHolder>(response) {
        @Override
        protected void onBindViewHolder(NoteViewHolder holder, int position, Note model) {
            final Note note = notesList.get(position);

            holder.title.setText(note.getTitle());
            holder.content.setText(note.getContent());
            Glide.with(MainActivity.this).load(note.getNote_image_url()).into(holder.bg_note_image);

            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    updateNote(note);
                }
            });
        }

        @Override
        public NoteViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_note_view, parent, false);
            return new NoteViewHolder(view);
        }

        @Override
        public void onError(FirebaseFirestoreException e) {
            Log.e("error", e.getMessage());
        }
    };

    adapter.notifyDataSetChanged();
    recyclerView.setAdapter(adapter);
}

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position) {
    if (viewHolder instanceof NoteViewHolder) {
        int pos = viewHolder.getAdapterPosition();
        String name = notesList.get(pos).getTitle();
        String id = notesList.get(pos).getId();

        // backup of removed item for undo purpose
        final Note deletedItem = notesList.get(viewHolder.getAdapterPosition());
        final int deletedIndex = viewHolder.getAdapterPosition();

        // remove the item from recycler view
        deleteNote(id);

        Snackbar snackbar = Snackbar.make(coordinatorLayout, name + " removed from cart!", Snackbar.LENGTH_LONG);
        snackbar.setAction("UNDO", new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // undo is selected, restore the deleted item
            }
        });
        snackbar.setActionTextColor(Color.YELLOW);
        snackbar.show();
    }
}

private void deleteNote(String id) {
    db.collection("users").document(firebase_user_uid).collection("notes")
            .document(id)
            .delete()
            .addOnCompleteListener(new OnCompleteListener<Void>() {
                @Override
                public void onComplete(@NonNull Task<Void> task) {
                    mFirebaseAnalytics.logEvent(NOTE_DELETED_EVENT, null);
                }
            });
}

@Override
public void onStart() {
    super.onStart();
    adapter.startListening();
}

@Override
public void onStop() {
    super.onStop();
    adapter.stopListening();
}}

Answer 1

因此，至少我确定了自己的答案。我重写了我的代码。因此，当我查看https://github.com/firebase/FirebaseUI-Android/blob/master/firestore/README.md#using-the-firestorerecycleradapter时，我注意到不需要创建自己的ArrayList。删除该列表并像在Firebase示例中那样编写代码后，它就起作用了。但是谢谢您的帮助。

必须在回收站上滚动查看项目可见

1 个答案: