我进行了一个活动，该活动在RecyclerView中显示用户列表（按名称排序）。而且RecyclerView对于第一个用户来说效果很好，但是从不显示列表的最后一个用户，这很奇怪，因为它应该加载所有数据。
public class UsersRecyclerAdapter extends RecyclerView.Adapter<UsersRecyclerAdapter.ViewHolder> {
public List<Users> usersList;
public Context context;
public UsersRecyclerAdapter(Context context, List<Users> usersList){
this.usersList = usersList;
this.context = context;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.users_single_layout, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
holder.nameText.setText(usersList.get(position).getName());
RequestOptions requestOptions = new RequestOptions();
requestOptions.placeholder(R.drawable.baseline_account_circle_black_24);
Glide.with(holder.nameText.getContext().getApplicationContext()).applyDefaultRequestOptions(requestOptions).load(usersList.get(position).getImage()).into(holder.profileImage);
final String user_id = usersList.get(position).userId;
holder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent profileIntent = new Intent(v.getContext(), ProfileActivity.class);
profileIntent.putExtra("user_id", user_id);
profileIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(profileIntent);
}
});
}
@Override
public int getItemCount() {
return usersList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
View mView;
public TextView nameText;
public CircleImageView profileImage;
public ViewHolder(@NonNull View itemView) {
super(itemView);
mView = itemView;
nameText = mView.findViewById(R.id.search_user_name);
profileImage = mView.findViewById(R.id.search_user_image);
}
}
}
public class UsersActivity extends AppCompatActivity {
private RecyclerView users_list_view;
private List<Users> users_list;
private Toolbar mToolbar;
private FirebaseFirestore firebaseFirestore;
private FirebaseAuth firebaseAuth;
private UsersRecyclerAdapter usersRecyclerAdapter;
private DocumentSnapshot lastVisible;
private Boolean isFirstPageFirstLoad = true;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_users);
mToolbar = findViewById(R.id.new_post_toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setTitle(R.string.all_users);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
users_list = new ArrayList<>();
users_list_view = findViewById(R.id.users_list_view);
firebaseAuth = FirebaseAuth.getInstance();
usersRecyclerAdapter = new UsersRecyclerAdapter(getApplicationContext(), users_list);
users_list_view.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
users_list_view.setAdapter(usersRecyclerAdapter);
users_list_view.setHasFixedSize(true);
if (firebaseAuth.getCurrentUser() != null) {
firebaseFirestore = FirebaseFirestore.getInstance();
users_list_view.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Boolean reachedBottom = !recyclerView.canScrollVertically(1);
if (reachedBottom) {
loadMorePost();
}
}
});
Query firstQuery = firebaseFirestore.collection("Users").orderBy("name", Query.Direction.ASCENDING).limit(3);
firstQuery.addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {
if (queryDocumentSnapshots != null && !queryDocumentSnapshots.isEmpty()) {
if (isFirstPageFirstLoad) {
lastVisible = queryDocumentSnapshots.getDocuments().get(queryDocumentSnapshots.size() - 1);
users_list.clear();
}
for (DocumentChange doc : queryDocumentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String userId = doc.getDocument().getId();
Users user = doc.getDocument().toObject(Users.class).withId(userId);
if (isFirstPageFirstLoad) {
users_list.add(user);
} else {
users_list.add(0, user);
}
usersRecyclerAdapter.notifyDataSetChanged();
}
}
isFirstPageFirstLoad = false;
}
}
});
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
finish();
break;
}
return true;
}
private void loadMorePost() {
if(firebaseAuth.getCurrentUser() != null) {
Query nextQuery = firebaseFirestore.collection("Users")
.orderBy("name", Query.Direction.ASCENDING)
.startAfter(lastVisible)
.limit(3);
nextQuery.addSnapshotListener(new EventListener<QuerySnapshot>() {
@Override
public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {
if (queryDocumentSnapshots != null && !queryDocumentSnapshots.isEmpty()) {
lastVisible = queryDocumentSnapshots.getDocuments().get(queryDocumentSnapshots.size() - 1);
for (DocumentChange doc : queryDocumentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String userId = doc.getDocument().getId();
Users user = doc.getDocument().toObject(Users.class).withId(userId);
users_list.add(user);
usersRecyclerAdapter.notifyDataSetChanged();
}
}
}
}
});
}
}
}
我认为Firestore查询存在问题，但我从未见过
非常感谢您的帮助：）