Я пытаюсь показать случайных пользователей из базы данных Firebase Realtime. В настоящее время я могу показать одного случайного пользователя из моей базы данных Firebase Realtime, но я хочу показать сразу 6 случайных пользователей в моем просмотрщике. Но я невозможно выяснить, как добавить запрос для того же, не получая ошибку во время выполнения.
Mycode
public class UsersFragment extends Fragment {
private RecyclerView recyclerView;
private UserAdapter mUserAdapter;
private List<User> mUsers;
String TAG = "MyTag";
ValueEventListener mValueEventListener;
List<String> UserIdsList = new ArrayList<>();
public UsersFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_users, container, false);
recyclerView = view.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
mUsers = new ArrayList<>();
//readUser();
RandomUsers();
return view;
}
private void RandomUsers() {
//mUsers.add((User) UserIdsList);
mUserAdapter = new UserAdapter(getContext(), mUsers, false);
recyclerView.setAdapter(mUserAdapter);
mUserAdapter.notifyDataSetChanged();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference UserIdsRef = rootRef.child("UserIds");
ValueEventListener mValueEventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot ds : dataSnapshot.getChildren()) {
String userIDS = ds.getKey();
UserIdsList.add(userIDS);
}
int UserListSize = UserIdsList.size();
Log.d(TAG, String.valueOf(UserListSize));
Random random=new Random();
int random1=random.nextInt(UserListSize);
// int Rdm= UserIdsList.get(new Random().nextInt(UserListSize));
DatabaseReference UserRef = rootRef.child("Users").child(UserIdsList.get(random1));
Log.d(TAG,"UserRef "+ String.valueOf(UserRef));
//new Random().nextInt(UserListSize)
ValueEventListener eventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
User user = dataSnapshot.getValue(User.class);
mUsers.add(user);
mUserAdapter.notifyDataSetChanged();
String name = dataSnapshot.child("First").getValue(String.class);
Log.d(TAG, "Name called "+name);
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.d(TAG, "Error: " + databaseError.toException()); //Don't ignore errors!
}
};
UserRef.addListenerForSingleValueEvent(eventListener);
//UserRef.addValueEventListener(eventListener);
Query query2 = UserRef.limitToFirst(2);
query2.addListenerForSingleValueEvent(eventListener);
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.d(TAG, "Error: " + databaseError.getMessage()); //Don't ignore errors!
}
};
UserIdsRef.addListenerForSingleValueEvent(mValueEventListener);
//UserIdsRef.addValueEventListener(mValueEventListener);
}
}
UserAdapter. java
public class UserAdapter extends RecyclerView.Adapter<UserAdapter.ViewHolder> {
private Context mContext;
private List<User> mUsers;
private List<String> UserIdsList;
private boolean ischat;
String theLastMessage;
public UserAdapter(Context mContext, List<User> mUsers,boolean ischat) {
this.mContext = mContext;
this.mUsers = mUsers;
this.ischat=ischat;
}
@NonNull
@Override
public UserAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view= LayoutInflater.from(mContext).inflate(R.layout.user_item,parent,false);
return new UserAdapter.ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull UserAdapter.ViewHolder holder, int position) {
final User user=mUsers.get(position);
holder.username.setText(user.getFirst());
if (user.getImageURL().equals("default")){
holder.profile_image.setImageResource(R.mipmap.ic_launcher);
} 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("UserName",user.getFirst());
intent.putExtra("userid", user.getId());
intent.putExtra("ImageURL",user.getImageURL());
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.username);
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 = "default";
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) {
}
});
}
}
Снимок данных
DataSnapshot { key = KRhmaWXCctMHbU1Z6NAWRGGw2ag2, value = {EmailId=abc@gmail.com, First=shivam} }