【发布时间】：2021-03-31 12:55:04
【问题描述】：
不知道为什么会显示“未连接适配器”
我在 showProducts() 中间设置了布局管理器和回收器视图；方法我还将适配器设置为回收站视图，但仍然说：“未连接适配器”找不到问题所在，我很乐意接受一些帮助。谢谢各位！
以下代码在屏幕上没有显示：
主要活动：
公共类 MainActivity 扩展 AppCompatActivity {
private RecyclerView rView;
private RecyclerView.LayoutManager layoutManager;
private List<Product> products;
private ProductAdapter productAdapter;
private DatabaseReference mDataBase;
private CardView cardView;
//Product
private String id;
private String name;
private String author;
private String genre;
private String description;
private double price;
private int stock;
private String image;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
products = new ArrayList<Product>();
mDataBase = FirebaseDatabase.getInstance().getReference();
cardView = (CardView) findViewById(R.id.cardView);
layoutManager = new LinearLayoutManager(this);
rView = (RecyclerView) findViewById(R.id.recyclerView);
rView.setHasFixedSize(true);
rView.setLayoutManager(layoutManager);
showProducts();
registerForContextMenu(rView);
}
private void showProducts() {
mDataBase.child("Products").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
products.clear();
for (DataSnapshot ds : dataSnapshot.getChildren()) {
name = ds.child("title").getValue().toString();
author = ds.child("author").getValue().toString();
genre = ds.child("genre").getValue().toString();
description = ds.child("description").getValue().toString();
price = Double.parseDouble(ds.child("price").getValue().toString());
stock = Integer.parseInt(ds.child("stock").getValue().toString());
image = ds.child("image").getValue().toString();
id = ds.getKey();
Product product = new Product(id, name, author, genre, description, price, stock, image);
products.add(product);
}
productAdapter = new ProductAdapter(products, R.layout.recycler_view, new ProductAdapter.OnItemClickListener() {
@Override
public void onItemClick(Product product, int position) {
}
}, new ProductAdapter.OnButtonClickListener() {
@Override
public void onButtonClick(Product product, int position) {
}
});
}
rView.setAdapter(productAdapter);
}
// Observa como pasamos el activity, con this. Podríamos declarar
// Activity o Context en el constructor y funcionaría pasando el mismo valor, this
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
}
适配器：
公共类 ProductAdapter 扩展 RecyclerView.Adapter
private Context context;
private List<Product> products;
private int layout;
private OnItemClickListener itemClickListener;
private OnButtonClickListener btnClickListener;
public ProductAdapter(List<Product> products, int layout, OnItemClickListener itemListener, OnButtonClickListener btnListener) {
this.products = products;
this.layout = layout;
this.itemClickListener = itemListener;
this.btnClickListener = btnListener;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(layout, parent, false);
context = parent.getContext();
ViewHolder vh = new ViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.bind(products.get(position), itemClickListener, btnClickListener);
}
@Override
public int getItemCount() {
return products.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public TextView author;
public TextView genre;
public TextView description;
public TextView price;
public TextView stock;
public ImageView image;
public Button btnDelete;
public ViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.textViewProductName);
author = (TextView) itemView.findViewById(R.id.textViewProductAuthor);
genre = (TextView) itemView.findViewById(R.id.textViewProductGenre);
description = (TextView) itemView.findViewById(R.id.textViewProductDescription);
price = (TextView) itemView.findViewById(R.id.textViewProductPrice);
stock = (TextView) itemView.findViewById(R.id.textViewProductStock);
image = (ImageView) itemView.findViewById(R.id.imageViewProduct);
btnDelete = (Button) itemView.findViewById(R.id.buttonDeleteCity);
}
public void bind(final Product product, final OnItemClickListener itemListener, final OnButtonClickListener btnListener) {
name.setText(product.getName());
description.setText(product.getDescription());
price.setText((int) product.getPrice());
Picasso.get().load(product.getImage()).fit().into(image);
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnListener.onButtonClick(product, getAdapterPosition());
}
});
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
itemListener.onItemClick(product, getAdapterPosition());
}
});
}
}
public interface OnItemClickListener {
void onItemClick(Product product, int position);
}
public interface OnButtonClickListener {
void onButtonClick(Product product, int position);
}
}
【问题讨论】：
-
嗯，你知道firebase里有没有数据吗？你知道这个监听器会不会触发？
-
你的 recyclerview 设置数据正确吗？因为它是警告而不是错误，而且对我来说也出现了很多次..
-
是的，Firebase 中有数据，应该正确设置数据
标签： android android-recyclerview android-adapter