FireBaseRecyclerAdapter未在Android应用中显示

Question

我的firebaserecyclerView没有显示在应用程序中，但数据已添加到firebase结构中

这是我的Firebase结构

我需要在recyclerview中显示费用名称和总计

主要活动

public class DayExpensesActivity extends AppCompatActivity {
private RecyclerView recyclerView;
FirebaseDatabase firebaseDatabase;
DatabaseReference databaseReference;
FirebaseRecyclerAdapter<Expenses,ExpenseViewHolder> firebaseRecyclerAdapter;
RecyclerView.LayoutManager layoutManager;
Query query;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_day_expenses);
recyclerView=(RecyclerView)findViewById(R.id.recyclerView);
    layoutManager=new LinearLayoutManager(this);
    recyclerView.setLayoutManager(layoutManager);
    firebaseDatabase=FirebaseDatabase.getInstance();
    databaseReference=firebaseDatabase.getReference();
    final Expenses expensesDate = new Expenses(username, monthyr, currentdate);
    query=databaseReference.child("users").child(expensesDate.getUsername()).child(expensesDate.getMonth()).child(expensesDate.getDate());
FirebaseRecyclerOptions<Expenses> options =
            new FirebaseRecyclerOptions.Builder<Expenses>()
                    .setQuery(query, Expenses.class)
                    .build();

    firebaseRecyclerAdapter=new FirebaseRecyclerAdapter<Expenses, ExpenseViewHolder>(options) {

        @Override
        protected void onBindViewHolder(@NonNull ExpenseViewHolder holder, int position, @NonNull Expenses model) {
            holder.expensesText.setText(model.getExpenseName());
            holder.totaltext.setText(model.getTotal());


      @NonNull
        @Override
        public ExpenseViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

            View view=LayoutInflater.from(parent.getContext()).inflate(R.layout.expenses_card_layout,parent,false);

            return new ExpenseViewHolder(view);
        }
    };

    firebaseRecyclerAdapter.notifyDataSetChanged();
    recyclerView.setAdapter(firebaseRecyclerAdapter);

ExpensesViewHolder

public class ExpenseViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

public TextView expensesText,totaltext;
public ImageButton addBtn,editBtn;

private ItemClickListener itemClickListener;

public void setItemClickListener(ItemClickListener itemClickListener){
    this.itemClickListener=itemClickListener;
}

public ExpenseViewHolder(View itemView) {
    super(itemView);

    expensesText=(TextView) itemView.findViewById(R.id.expensestext);
    totaltext=(TextView) itemView.findViewById(R.id.totaltxt);
    addBtn=(ImageButton)itemView.findViewById(R.id.add_btn);
    editBtn=(ImageButton)itemView.findViewById(R.id.btn_edt);

    itemView.setOnClickListener(this);

}

@Override
public void onClick(View v) {


    itemClickListener.onClick(v,getAdapterPosition(),false);

}
}

Answer 1

要简单地显示这两个值，请使用以下代码：

DatabaseReference ref = databaseReference
    .child("users")
    .child(expensesDate.getUsername())
    .child("Expenses")
    .child(expensesDate.getMonth())
    .child(expensesDate.getDate());

现在，您可以添加一个侦听器来读取这些值：

ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
            String expenseName = dataSnapshot.child("expenseName").getValue(String.class);
            String total = dataSnapshot.child("total").getValue(String.class);
            Log.d("TAG", expenseName + " / " + total);
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        Log.d(TAG, databaseError.getMessage());
    }
};
ref.addListenerForSingleValueEvent(valueEventListener);

您的logcat中的输出将是：

pegrol / 76

由于使用RecyclerView来回收视图，因此无需在RecyclerView中显示这些值，并且在您的情况下，也无需回收单个视图。