[英]RecyclerView shows the same item many times in my app
I've created a match system in my Android program that also includes a chat section which has 2 fragments.我在我的 Android 程序中创建了一个匹配系统,该系统还包括一个包含 2 个片段的聊天部分。 The first fragment shows your chats, the second one shows your matches by using
RecyclerView
and UsersAdapter
.第一个片段显示您的聊天记录,第二个片段使用
RecyclerView
和UsersAdapter
显示您的匹配项。 However, in the second (match) fragment, people who you matched with are shown many times.但是,在第二个(匹配)片段中,您匹配的人被多次显示。 For example, the same person is seen many times as you can see here .
例如,您可以在此处看到同一个人多次出现。
My code is below.我的代码如下。
UserFragment:用户片段:
public class UsersFragment extends Fragment {
private RecyclerView recyclerView;
private UsersAdapter usersAdapter;
private List<User> mUsers;
FirebaseFirestore usersfragmentstore;
FirebaseAuth readauth;
DocumentReference readref;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
usersfragmentstore = FirebaseFirestore.getInstance();
readauth = FirebaseAuth.getInstance();
View view = inflater.inflate(R.layout.fragment_users, container, false);
readref = usersfragmentstore.collection("users").document(readauth.getCurrentUser().getUid());
recyclerView = view.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
mUsers = new ArrayList<>();
final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
DatabaseReference reference = FirebaseDatabase.getInstance().getReference("users");
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
readref.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
DocumentSnapshot shot = task.getResult();
List<String> matchedid2 = new ArrayList<>();
matchedid2 = (List<String>) shot.get("matchlist");
if (matchedid2.contains(snapshot.getKey())) {
User user = snapshot.getValue(User.class);
mUsers.add(user);
usersAdapter = new UsersAdapter(getContext(), mUsers, false);
recyclerView.setAdapter(usersAdapter);
}
}
});
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
return view;
}
}
UserAdapter:用户适配器:
public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.ViewHolder> {
private Context mContext;
private List<User> mUsers;
private boolean ischat;
String theLastMessage;
public UsersAdapter(Context mContext, List<User> mUsers, boolean ischat) {
this.mUsers = mUsers;
this.mContext = mContext;
this.ischat = ischat;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mContext).inflate(R.layout.user_item_chat, parent, false);
return new UsersAdapter.ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
User user = mUsers.get(position);
holder.username.setText(user.getName());
if (user.getImageURL().equals("default")) {
holder.profile_image.setImageResource(R.drawable.profilepicture);
} else {
Glide.with(mContext).load(user.getImageURL()).into(holder.profile_image);
}
if (ischat) {
lastMessage(user.getId(), holder.last_msg);
} else {
holder.last_msg.setVisibility(View.GONE);
}
if (ischat) {
if (user.getStatus().equals("online")) {
holder.img_on.setVisibility(View.VISIBLE);
holder.img_off.setVisibility(View.GONE);
} else {
holder.img_on.setVisibility(View.GONE);
holder.img_off.setVisibility(View.VISIBLE);
}
} else {
holder.img_on.setVisibility(View.GONE);
holder.img_off.setVisibility(View.GONE);
}
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(mContext, MessageActivity.class);
intent.putExtra("userid", user.getId());
mContext.startActivity(intent);
}
});
}
@Override
public int getItemCount() {
return mUsers.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView username;
public ImageView profile_image;
private ImageView img_on;
private ImageView img_off;
private TextView last_msg;
public ViewHolder(@NonNull View itemView) {
super(itemView);
username = itemView.findViewById(R.id.chatusername);
profile_image = itemView.findViewById(R.id.profile_image);
img_on = itemView.findViewById(R.id.img_on);
img_off = itemView.findViewById(R.id.img_off);
last_msg = itemView.findViewById(R.id.last_msg);
}
}
private void lastMessage(final String userid, final TextView last_msg) {
theLastMessage = "defalut";
final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Chats");
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
Chat chat = snapshot.getValue(Chat.class);
if (firebaseUser != null && chat != null) {
if (chat.getReceiver().equals(firebaseUser.getUid()) && chat.getSender().equals(userid) || chat.getReceiver().equals(userid) && chat.getSender().equals(firebaseUser.getUid())) {
theLastMessage = chat.getMessage();
}
}
}
switch (theLastMessage) {
case "default":
last_msg.setText("No message");
break;
default:
last_msg.setText(theLastMessage);
break;
}
theLastMessage = "default";
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
}
What am I missing?我错过了什么?
befor adding new data first clear list by mUsers.clear();
在添加新数据之前,首先通过
mUsers.clear();
as below如下
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
readref.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
DocumentSnapshot shot = task.getResult();
List<String> matchedid2 = new ArrayList<>();
matchedid2 = (List<String>) shot.get("matchlist");
if (matchedid2.contains(snapshot.getKey())) {
mUsers.clear();
User user = snapshot.getValue(User.class);
mUsers.add(user);
usersAdapter = new UsersAdapter(getContext(), mUsers, false);
recyclerView.setAdapter(usersAdapter);
}
}
});
}
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