我有以下FirestoreRecyclerAdapter
public class AdaptadorVentaCervezas extends FirestoreRecyclerAdapter<Cerveza, AdaptadorVentaCervezas.ViewHolder> {
public AdaptadorVentaCervezas(@NonNull FirestoreRecyclerOptions<Cerveza> options) {
super(options);
}
@Override
public AdaptadorVentaCervezas.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.venta_cervezas, parent, false);
return new AdaptadorVentaCervezas.ViewHolder(view);
}
class ViewHolder extends RecyclerView.ViewHolder {
public TextView txtNombre, txtCantidad;
public Button btnMenos, btnMas;
public String CervezaID;
public ViewHolder(View itemView) {
super(itemView);
txtNombre = (TextView) itemView.findViewById(R.id.txtNombre);
txtCantidad = (TextView) itemView.findViewById(R.id.txtCantidad);
btnMenos = (Button) itemView.findViewById(R.id.btMenosCerveza);
btnMenos.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int cantidad = VentaActivity.cantidadCervezaMap.get(CervezaID)-1;
VentaActivity.cantidadCervezaMap.put(CervezaID, cantidad);
txtCantidad.setText(Integer.toString(cantidad));
}
});
btnMas = (Button) itemView.findViewById(R.id.btMasCerveza);
btnMas.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int cantidad = VentaActivity.cantidadCervezaMap.get(CervezaID)+1;
VentaActivity.cantidadCervezaMap.put(CervezaID, cantidad);
txtCantidad.setText(Integer.toString(cantidad));
}
});
}
}
@Override
protected void onBindViewHolder(@NonNull AdaptadorVentaCervezas.ViewHolder holder, int position, @NonNull Cerveza item) {
holder.txtNombre.setText(item.getNombre());
holder.CervezaID = item.getId(); //Id the field, not the ID of the document
VentaActivity.cervezaMap.put(holder.CervezaID,item);
VentaActivity.cantidadCervezaMap.put(holder.CervezaID, 0);
}
}
在主要活动中，实现如下
Query query = FirebaseFirestore.getInstance()
.collection("Cervezas").whereEqualTo("disponibilidad", true)
.limit(50);
opciones = new FirestoreRecyclerOptions
.Builder<Cerveza>().setQuery(query, Cerveza.class).build();
adaptador = new AdaptadorVentaCervezas(opciones);
recyclerView = findViewById(R.id.reciclerViewVentaCervezas);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(adaptador);
这工作得很好。现在，我在尝试向主要活动添加按钮时遇到了麻烦，即单击该按钮时会将 txtCantidad 的“ 0”分配给recyclerview的每个项目。如何访问recyclerview的textViews并设置新文本？
谢谢
答案 0 :(得分：-1)
从此示例中为您的解决方案选择一两个想法
public class HomeFragment extends Fragment {
private RecyclerView blog_list_view;
private List<BlogPost> blog_list;
private FirebaseFirestore firebaseFirestore;
private FirebaseAuth firebaseAuth;
private BlogRecyclerAdapter blogRecyclerAdapter;
private DocumentSnapshot lastVisible;
private Boolean isFirstPageFirstLoad = true;
public HomeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
blog_list = new ArrayList<>();
blog_list_view = view.findViewById(R.id.blog_list_view);
firebaseAuth = FirebaseAuth.getInstance();
blogRecyclerAdapter = new BlogRecyclerAdapter(blog_list);
blog_list_view.setLayoutManager(new LinearLayoutManager(container.getContext()));
blog_list_view.setAdapter(blogRecyclerAdapter);
blog_list_view.setHasFixedSize(true);
if(firebaseAuth.getCurrentUser() != null) {
firebaseFirestore = FirebaseFirestore.getInstance();
blog_list_view.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Boolean reachedBottom = !recyclerView.canScrollVertically(1);
if(reachedBottom){
loadMorePost();
}
}
});
Query firstQuery = firebaseFirestore.collection("Posts").orderBy("timestamp", Query.Direction.DESCENDING).limit(3);
firstQuery.addSnapshotListener(getActivity(), new EventListener<QuerySnapshot>() {
@Override
public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {
if (!documentSnapshots.isEmpty()) {
if (isFirstPageFirstLoad) {
lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);
blog_list.clear();
}
for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String blogPostId = doc.getDocument().getId();
BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);
if (isFirstPageFirstLoad) {
blog_list.add(blogPost);
} else {
blog_list.add(0, blogPost);
}
blogRecyclerAdapter.notifyDataSetChanged();
}
}
isFirstPageFirstLoad = false;
}
}
});
}
// Inflate the layout for this fragment
return view;
}
public void loadMorePost(){
if(firebaseAuth.getCurrentUser() != null) {
Query nextQuery = firebaseFirestore.collection("Posts")
.orderBy("timestamp", Query.Direction.DESCENDING)
.startAfter(lastVisible)
.limit(3);
nextQuery.addSnapshotListener(getActivity(), new EventListener<QuerySnapshot>() {
@Override
public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {
if (!documentSnapshots.isEmpty()) {
lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);
for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {
if (doc.getType() == DocumentChange.Type.ADDED) {
String blogPostId = doc.getDocument().getId();
BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);
blog_list.add(blogPost);
blogRecyclerAdapter.notifyDataSetChanged();
}
}
}
}
});
}
}
}