问题描述
我有 Spinner 有 Student classNames(ist-8th)。当我选择 One class 时，recyclerview 中会显示与该项目相关的 firestore 多个文档。但是，当我选择另一个类时，文档会堆积在前一个类的下方。我只希望那些与 Spinner 的 className 具有相同字段的文档保留在 recyclerview 上。
ClassViewActivity 的代码是..
public class ViewClasswise extends AppCompatActivity {
private static final String TAG = ViewClasswise.class.getSimpleName();
private RecyclerView recyclerViewCW;
ArrayList<ModelViewClasswise>classlist;
FirebaseFirestore db;
FirebaseAuth fAuth;
ClasswiseAdapter classwiseAdapter;
Spinner s1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_classwise);
recyclerViewCW = findViewById(R.id.recyclerviewCW);
recyclerViewCW.addItemdecoration(new DividerItemdecoration(this,DividerItemdecoration.VERTICAL));
recyclerViewCW.setLayoutManager(new linearlayoutmanager(this));
classlist=new ArrayList<>();
classwiseAdapter=new ClasswiseAdapter(classlist);
recyclerViewCW.setAdapter(classwiseAdapter);
s1=findViewById(R.id.spinnerSearch);
db= FirebaseFirestore.getInstance();
fAuth= FirebaseAuth.getInstance();
FirebaseUser user = fAuth.getCurrentUser();
//spinner Listener
s1.setonItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView,View view,int position,long id) {
String selectedClass = (String) parentView.getItemAtPosition(position);
db.collection("Schools").document(user.getUid()).collection("Students")
.whereEqualTo("className",selectedClass)
.get()
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
@Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
List<DocumentSnapshot> list=queryDocumentSnapshots.getDocuments();
for(DocumentSnapshot d:list){
ModelViewClasswise obj=d.toObject(ModelViewClasswise.class);
classlist.add(obj);
}
//Update Adapter
classwiseAdapter.notifyDataSetChanged();
}
});
}
@Override
public void onnothingSelected(AdapterView<?> parent) {
}
});
}
}
适配器代码是....
public class ClasswiseAdapter extends RecyclerView.Adapter<ClasswiseAdapter.studentViewHolder>{
private static final String TAG =ClasswiseAdapter.class.getSimpleName() ;
private ArrayList<ModelViewClasswise> classlist;
private ArrayList<ModelViewClasswise> newClassList;
public ClasswiseAdapter(ArrayList<ModelViewClasswise> classlist) {
this.classlist = classlist;
}
public void addnewList(ArrayList<ModelViewClasswise> newClassList){
this.classlist = newClassList;
notifyDataSetChanged();
}
@NonNull
@Override
public ClasswiseAdapter.studentViewHolder onCreateViewHolder(@NonNull ViewGroup parent,int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.row_classwise,parent,false);
return new ClasswiseAdapter.studentViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull studentViewHolder holder,int position) {
holder.t1.setText(classlist.get(position).getName());
holder.t2.setText(classlist.get(position).getClassName());
holder.t3.setText(classlist.get(position).getRollNumber());
}
@Override
public int getItemCount() {
return classlist.size();
}
class studentViewHolder extends RecyclerView.ViewHolder{
TextView t1,t2,t3;
public studentViewHolder(@NonNull View itemView) {
super(itemView);
t1=itemView.findViewById(R.id.nameC);
t2=itemView.findViewById(R.id.classC);
t3=itemView.findViewById(R.id.rollNumC);
}
}
}
解决方法
谢谢大家！我加了
classlist.clear()
它奏效了