Android 循环视图中的列表比显示的数据多

列出Account类中两个服务提供商（保姆和儿童活动策划人）的所有信息

public class Register_Requests extends Fragment {
FirebaseAuth mAuth;
DatabaseReference refAccount,searchdatabase;
FirebaseUser user;
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
RecyclerView recyclerView;
Adapter adapter;
TextView Fullname_Admin;
Button btnlogOutAdmin,search_bar;
String F_name, L_name;
ArrayList<Account> list = new ArrayList();
private String mParam1;
private String mParam2;

public Register_Requests() { }


public static Register_Requests newInstance(String param1, String param2) {
    Register_Requests fragment = new Register_Requests();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);}}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View view= inflater.inflate(R.layout.fragment_register__requests, container, false);
    ImageView imgfake;
    TextView nametext,SPtext,count;
    imgfake=view.findViewById(R.id.imgfake);
    nametext=view.findViewById(R.id.nametext);
    SPtext=view.findViewById(R.id.SPtext);
    count= (TextView) view.findViewById(R.id.counttext);
    btnlogOutAdmin = view.findViewById(R.id.signout_admin);
    Fullname_Admin= (TextView) view.findViewById(R.id.name_admin);
    recyclerView =(RecyclerView)view.findViewById(R.id.recview_SP);
    recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
    user= FirebaseAuth.getInstance().getCurrentUser();
    refAccount = FirebaseDatabase.getInstance().getReference().child("Account");
    String Id_admin = FirebaseAuth.getInstance().getCurrentUser().getUid();

    // Welcome admin
     FirebaseDatabase.getInstance().getReference("Admin").child(Id_admin)
            .addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
           Admin admin_display = snapshot.getValue(Admin.class);
           if(admin_display != null){
               F_name = admin_display.getA_FullName();
               L_name = admin_display.getA_LastName();
               Fullname_Admin.setText("Welcome "+F_name+" "+L_name+" !");}}

        @Override
        public void onCancelled(@NonNull DatabaseError error) {
            Toast.makeText(getActivity(),"Something Wrong Happened",Toast.LENGTH_SHORT).show();}});

    // Logout admin
    btnlogOutAdmin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            FirebaseAuth.getInstance().signOut();
            perfrences.clearData(getActivity());
            getActivity().finish();
            startActivity(new Intent(getActivity(),Login.class));}});

    // List Babysitter and Kids Event Planner from Account
    refAccount.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            list.clear();
            if (snapshot.exists())
            {
                for (DataSnapshot snapshot1: snapshot.getChildren())
                {
                    Account a=snapshot1.getValue(Account.class);
                    list.add(a);
                }
                adapter.notifyDataSetChanged();
                count.setText(adapter.getItemCount()+" Registers"); }
            else
            { nametext.setText("No Available Service Providers");
                nametext.setVisibility(View.VISIBLE);} }

        @Override
        public void onCancelled(@NonNull DatabaseError error) {
        }
    });
    // Adapter for recycle view
    FirebaseRecyclerOptions<Account> options =
            new FirebaseRecyclerOptions.Builder<Account>()
                    .setQuery(refAccount, Account.class)
                    .build();

    adapter = new Adapter(options);
    recyclerView.setAdapter(adapter);
    adapter.startListening();
    return view;


}


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

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

正如您在account_角色中看到的，这是3个用户，第4个是家长

帐户路径中有16个节点

这些是（服务提供商）的其他路径，共有8个节点

问题是我只调用了服务提供者的信息，它应该在recycle视图中显示8个项目，但这里显示account类中的其余项目，总共16个项目，这意味着显示了8个项目的数据，但其余的是空的，我想显示项目列表作为服务提供者的大小。那么我该如何预防这个问题呢

---

它显示Account类中的空行。

要仅从

/Account

下获取子节点，并为

Account\u role

指定值，您可以使用查询：

但您只能对单个值（如上面的

babbysitor

）或连续的值范围（如：从

Admin

到

babbysitor

）执行此操作。无法请求（使用单个查询）所需的多个不同值

一些选择：

对每个值执行查询（如上面所示），然后将结果合并到客户端代码中。它的性能会很好，但代码会多一点

为每个子节点指定一个与您的条件完全匹配的属性，例如：

“Babbysetter\u或\u KidsEventPlanner”：true

。然后您可以对该属性进行筛选。如果这样的组合数量有限，这种方法效果最好

对一系列值执行查询，例如：

ref.orderByChild（“account\u role”）.startAt（“保姆”）.endAt（“Kids Event Planner”）

。请记住，这将返回

帐户\u角色

值介于

保姆

和

儿童活动计划器

之间的所有节点，因此它还将包括

汽车修理工

的节点。不过，有时这是一个不错的选择，特别是如果您可以根据查询需要对值进行排序/重命名

---

欢迎来到堆栈溢出。请在此处将所有相关代码包括在您的问题中，因为文本如屏幕截图所示，

帐户下至少有11个节点。为什么你认为列表应该只显示8个项目？@FrankvanPuffelen因为我在Account类中保存了所有4个用户ID，所以可以通过其在应用程序中的角色和ID轻松调用它。但是在这种情况下，我只想检索两个仅限用户的保姆和儿童活动策划人的信息。您的代码如何过滤它加载到仅限保姆和儿童活动策划人的数据？请记住：您共享了很多代码，而堆栈溢出是一个众所周知的效率低下的交互式调试器。您需要准确地告诉我们问题发生在代码的什么地方。@FrankvanPuffelen运行时没有编译器错误。我已经将4个用户的帐户注册的所有相关数据存储在一个类“account”中，其余的注册信息通过他们自己的类存储。在上面的例子中，我只想从整个account类中检索两个用户的信息，这两个用户是Baby保姆和kids Event Planner（他们总共有8个节点）。我希望我的解释对你来说是清楚的：）非常感谢你，我真的很感谢你的努力。但我想知道。。。如果我选择执行第一个选项，我将如何组合2个查询并将它们添加到InferebaseRecyclerOptions中以完成其余的工作，因为我有特定的数据来检索它。在这种情况下，您将无法使用FirebaseUI中的适配器，因为它们只能显示单个查询的结果。但是您可以将项目添加到
列表中，然后在该列表上创建适配器。这并不像你想象的那么难。例如，请参阅，更多信息来自：听起来不错。谢谢，不客气。
public class Adapter extends FirebaseRecyclerAdapter<Account, Adapter.viewHolder>  {
    DatabaseReference Ref,Ref2,check;
    boolean flag =true, flag2=true;
    String userIDs,total_count,IDsitter,IDplanner;

    public Adapter(@NonNull FirebaseRecyclerOptions<Account> options) { super(options); }

    @Override
    protected void onBindViewHolder(@NonNull viewHolder holder, int position, @NonNull Account model) {
        Ref= FirebaseDatabase.getInstance().getReference("Babysitter");
        Ref2= FirebaseDatabase.getInstance().getReference("Kids Event Planner");
        userIDs = model.user_id;

        // Print all the Babysitter
        Ref.child(userIDs).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
             if(snapshot.exists()){

                 if(snapshot.hasChild("b_FirstName")){
                 String Fname = snapshot.child("b_FirstName").getValue().toString();
                 String Lname = snapshot.child("b_LastName").getValue().toString();
                 String photo = snapshot.child("b_Photo").getValue().toString();
                 String gender = snapshot.child("b_Gender").getValue().toString();
                 String nationality = snapshot.child("b_Nationality").getValue().toString();
                 String phone = snapshot.child("b_Phone").getValue().toString();
                 String B_date = snapshot.child("b_BirthDate").getValue().toString();
                 int Y_e = parseInt(snapshot.child("years_of_Experience").getValue().toString());
                 String exp= Integer.toString(Y_e);
                 String state= snapshot.child("registration_Status").getValue().toString();
                 String educate= snapshot.child("b_EducationLevel").getValue().toString();


                 holder.nametext.setText(Fname +" "+ Lname );
                 holder.SPtext.setText(model.getAccount_role());
                 Picasso.with(holder.imgfake.getContext()).load(photo).placeholder(R.drawable.ic_action_name).into(holder.imgfake);

                 holder.itemView.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View view) {
                 AppCompatActivity activity=(AppCompatActivity)view.getContext();
                 activity.getSupportFragmentManager().beginTransaction().replace(R.id.container, new eachInfo_SP(model.user_id,Fname,Lname,photo,
                 gender,nationality,phone,B_date,model.getAccount_email(),model.getAccount_role(), exp,state,educate)).addToBackStack(null).commit();}});}
                 else { flag=false;System.out.println("No values");} if (!(model.account_role.equals("Admin"))&& !(model.account_role.equals("Parent")) ){
                     // Log.e(String.valueOf(snapshot.getKey().equals(userIDs)), snapshot.getChildrenCount() + " Registers");
                     total_count = snapshot.getChildrenCount() + " Registers";
                     System.out.println(total_count);
                 }}}

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

            // Print all the KEP
            Ref2.child(userIDs).addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot snapshot) {
                    if(snapshot.exists()){
                        KidsEventPlanner k= snapshot.getValue(KidsEventPlanner.class);

                    if(snapshot.hasChild("e_FirstName")){
                    String Fname = snapshot.child("e_FirstName").getValue().toString();
                    String Lname = snapshot.child("e_LastName").getValue().toString();
                    String photo = snapshot.child("e_Photo").getValue().toString();
                    String gender = snapshot.child("e_Gender").getValue().toString();
                    String nationality = snapshot.child("e_Nationality").getValue().toString();
                    String phone = snapshot.child("e_Phone").getValue().toString();
                    String B_date = snapshot.child("e_BirthDate").getValue().toString();
                    int Y_e = parseInt(snapshot.child("years_of_experience").getValue().toString());
                    String exp= Integer.toString(Y_e);
                    String state= snapshot.child("registration_status").getValue().toString();
                    String educate= snapshot.child("e_EducationLevel").getValue().toString();


                    holder.nametext.setText(Fname +" "+ Lname );
                    holder.SPtext.setText(model.getAccount_role());
                    Picasso.with(holder.imgfake.getContext()).load(photo).placeholder(R.drawable.ic_action_name).into(holder.imgfake);

                    holder.itemView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                    AppCompatActivity activity=(AppCompatActivity)view.getContext();
                    activity.getSupportFragmentManager().beginTransaction().replace(R.id.container, new eachInfo_SP(model.user_id,Fname,Lname,photo,
                    gender,nationality,phone,B_date,model.getAccount_email(),model.getAccount_role(), exp, state,educate)).addToBackStack(null).commit();}});}
                    else{flag2 = false; System.out.println("False");}} }

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

    }

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

    public class viewHolder extends RecyclerView.ViewHolder
    {
        ImageView imgfake;
        TextView nametext,SPtext,count;
        public viewHolder(@NonNull View itemView) {
            super(itemView);
            imgfake=itemView.findViewById(R.id.imgfake);
            nametext=itemView.findViewById(R.id.nametext);
            SPtext=itemView.findViewById(R.id.SPtext);
            count= (TextView) itemView.findViewById(R.id.counttext);}}

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

}

public class Account  {

    String account_email,account_password ,account_role, user_id;

    public Account() {}

    public Account(String account_email, String account_password, String account_role, String user_id) {
        this.account_email = account_email;
        this.account_password = account_password;
        this.account_role = account_role;
        this.user_id = user_id;
    }

    public String getAccount_email() {return account_email;}

    public void setAccount_email(String account_email) {this.account_email = account_email;}

    public String getAccount_password() {return account_password;}

    public void setAccount_password(String account_password) {this.account_password = account_password; }

    public String getAccount_role() {return account_role;}

    public void setAccount_role(String account_role) {this.account_role = account_role; }

    public String getUser_id() { return user_id; }

    public void setUser_id(String user_id) { this.user_id = user_id;}
}

DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Account");
Query query = ref.orderByChild("account_role").equalTo("Babysitter");
query. addListenerForSingleValueEvent(...