此处CourseName来自上一个活动。问题在于，输出中每次都打印一个额外的回收者视图项。另外，我在其中输入了“ userInfo”的db id数据库引用，以便从回收者视图中获取名称的值。
您能告诉我如何按值顺序检索CourseName的值吗？
@Override
public void onResume() {
super.onResume();
database =
FirebaseDatabase.getInstance().getReference("CoursesRegister");
FirebaseRecyclerOptions<StudentModel> options = new
FirebaseRecyclerOptions.Builder<StudentModel>()
.setQuery(database, StudentModel.class).build();
FirebaseRecyclerAdapter adapter = new
FirebaseRecyclerAdapter<StudentModel,UserViewHolder>(options) {
@Override
protected void onBindViewHolder(final
ShowStudentByCourse.UserViewHolder holder, int position, @NonNull
final StudentModel studentModel) {
final String selected_user_id = getRef(position).getKey();
database.child(selected_user_id)
.orderByValue().equalTo(CourseName).addListenerForSingleValueEvent(new
ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot)
{
if (dataSnapshot.exists()) {
Toast.makeText(ShowStudentByCourse.this, "id
\n"+dataSnapshot.getKey(), Toast.LENGTH_SHORT).show();
db.child(dataSnapshot.getKey()).addListenerForSingleValueEvent(new
ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot
dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot
dataSnapshot1:dataSnapshot.getChildren()) {
name =
dataSnapshot.child("Name").getValue().toString();
holder.uName.setText(name);
// }
}
@Override
public void onCancelled(@NonNull DatabaseError
databaseError) {
}
});
}
}
@Override
public void onCancelled(@NonNull DatabaseError
databaseError) {
}
});
}
@NonNull
@Override
public ShowStudentByCourse.UserViewHolder
onCreateViewHolder(@NonNull ViewGroup parent, int i) {
View view =
LayoutInflater.from(parent.getContext()).inflate(R.layout.add_student,
parent, false);
return new ShowStudentByCourse.UserViewHolder(view);
}
};
recyclerView.setAdapter(adapter);
adapter.startListening();
}
public static class UserViewHolder extends RecyclerView.ViewHolder {
public CircleImageView profileImg;
ListView listView;
TextView uName,uStatus,Uid,uNameValue,uSubjectValue;
View mView;
public UserViewHolder(View itemView) {
super(itemView);
mView = itemView;
uName = mView.findViewById(R.id.category_name);
Uid = mView.findViewById(R.id.id_Course);
uStatus = mView.findViewById(R.id.course_code);
uNameValue = mView.findViewById(R.id.course_code_text);
uSubjectValue = mView.findViewById(R.id.course_name);
}
}