在Firebase中删除一行后，如何在Recycleview适配器中刷新数据

Question

我使用了带有cardivew的Recycleview以及数据列表和按钮来删除任何值。当我单击按钮时，它的确从Firebase数据库中删除了该值，但文本和行仍保留在应用程序的适配器中，但仅当我通过返回并重新打开关闭活动，然后行为空时。

我每次在两个地方使用下面的方法（我也在代码中显示过），但是它不起作用

                         bookslist.remove(position);   
                         notifyDataSetChanged();       

当我点击删除按钮时，如何立即更新回收视图

这是我的代码

public class SubjectBooksAdapter extends RecyclerView.Adapter<SubjectBooksAdapter.MyViewHolder> {
    ArrayList<Books> bookslist;

    FirebaseDatabase database;
    DatabaseReference dbreference;


    public SubjectBooksAdapter(ArrayList<Books> bookslist){
        this.bookslist = bookslist;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout,parent,false);
        return new MyViewHolder(v);



    }

    public class MyViewHolder extends RecyclerView.ViewHolder {

   
          Button mSolved;
 




        MyViewHolder(final View itemView) {
            super(itemView);
 
            database = FirebaseDatabase.getInstance();
            dbreference = database.getReference("roomrequest");
             dbreference.keepSynced(true);

            mSolved = (Button) itemView.findViewById(R.id.book_solved);
            mSolved.setTransformationMethod(null);


            fauth = FirebaseAuth.getInstance();



        }
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {

        database = FirebaseDatabase.getInstance();
        dbreference = database.getReference("roomrequest");
        
   
        holder.mSolved.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               



                    DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
                    DatabaseReference classicalMechanicsRef = rootRef.child("roomrequest").child("request").child(g.getRequestid());
                    ValueEventListener valueEventListener = new ValueEventListener() {

                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {
                            dataSnapshot.getRef().removeValue();
                             bookslist.remove(position);   \\ Solution One
                             notifyDataSetChanged();       \\ Solution One
                    
                        }

                        @Override
                        public void onCancelled(@NonNull DatabaseError databaseError) {

                        }
                    };
                    classicalMechanicsRef.addListenerForSingleValueEvent(valueEventListener);
                             bookslist.remove(position);   \\ Solution Two
                             notifyDataSetChanged();       \\ Solution Two
                    
                }
            
        });



 }



    @Override
    public int getItemCount() {
        return bookslist.size();
    }
}

Answer 1

使用 Row( mainAxisAlignment: MainAxisAlignment.start, children: <Widget>[ Container( width: MediaQuery.of(context).size.width * 0.42, child: Padding( padding: EdgeInsets.only(left: 0.0), child: Text("الجنس"))), Flexible( child: new DropdownButtonHideUnderline( child: new DropdownButton<String>( value: _data.gender, isDense: true, onChanged: (String newValue) { setState(() { _data.gender = newValue; }); }, items: genders.map((String value) { return new DropdownMenuItem<String>( value: value, child: new Text(value), ); }).toList(), ), ), ), ], ),

例如-

notifyItemRemoved(position);