我有一个recyclerview。我想从其适配器类更新回收器视图。
我尝试了notiftDataSetChanged( )，但是它只能在主类中使用。
下面是recyclerview适配器类的代码。
package com.library.apple.food;
import android.content.Context;
import android.content.Intent;
public class CartAdapter extends
RecyclerView.Adapter<CartAdapter.MyViewHolder> {
private Context context;
private List<CartItem> list;
private String auth_token;
private RecyclerView recyclerView;
public CartAdapter(Context context, List<CartItem> list, String
auth_token, RecyclerView recyclerView){
this.context = context;
this.list = list;
this.auth_token = auth_token;
this.recyclerView = recyclerView;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup,
int i) {
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.row_cart,viewGroup,false);
CartAdapter.MyViewHolder myViewHolder = new
CartAdapter.MyViewHolder(view);
return myViewHolder;
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder viewHolder,
final int i) {
final CartItem item = list.get(i);
viewHolder.title_cart.setText(item.getTitle_cart());
viewHolder.no_cart.setText(item.getNo_cart());
String price1 = context.getString(R.string.price,item.getPrice_cart());
viewHolder.price_cart.setText(price1);
String veg = item.getVegnon_cart();
if (veg.equalsIgnoreCase("false")) {
viewHolder.vegnon_cart.setImageResource(R.drawable.non_veg);
}
//-----------------------------------------------------------------------------
//cart plus button
viewHolder.btn_plus_cart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
String url_plus = "https://www.hungermela.com/api/v1/change-quantity/";
final String item_id = item.getCart_item_id();
RequestQueue queue = Volley.newRequestQueue(context);
StringRequest postRequest = new StringRequest(Request.Method.POST, url_plus,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// response
Log.d("Response", response);
//HERE I WANT TO UPDATE MY RECYCLERVIEW
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// error
Log.d("Error.Response", error.toString());
}
}
) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Authorization", "Token "+auth_token);
return params;
}
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("pk", item_id);
int quantity = Integer.parseInt(item.getNo_cart());
String quan = String.valueOf(quantity+1);
params.put("quantity",quan);
return params;
}
};
queue.add(postRequest);
}
});
//cart plus ends here
//-----------------------------------------------------------------------------
//cart minus button
viewHolder.btn_minus_cart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
int quantity = Integer.parseInt(item.getNo_cart());
if(quantity==1){
String url_minus = "https://www.hungermela.com/api/v1/delete-item/";
final String item_id = item.getCart_item_id();
RequestQueue queue = Volley.newRequestQueue(context);
StringRequest postRequest = new StringRequest(Request.Method.POST, url_minus,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// response
Log.d("Response", response);
AppCompatActivity activity = (AppCompatActivity) view.getContext();
Fragment myFragment = new CartFragment();
activity.getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, myFragment).addToBackStack(null).commit();
notifyDataSetChanged();
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// error
Log.d("Error.Response", error.toString());
}
}
) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Authorization", "Token "+auth_token);
return params;
}
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("pk", item.getId_id());
return params;
}
};
queue.add(postRequest);
}
else if(quantity > 1){
String url_minus = "https://www.hungermela.com/api/v1/change-quantity/";
final String item_id = item.getCart_item_id();
RequestQueue queue = Volley.newRequestQueue(context);
StringRequest postRequest = new StringRequest(Request.Method.POST, url_minus,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// response
Log.d("Response", response);
AppCompatActivity activity = (AppCompatActivity) view.getContext();
Fragment myFragment = new CartFragment();
activity.getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, myFragment).addToBackStack(null).commit();
notifyDataSetChanged();
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// error
Log.d("Error.Response", error.toString());
}
}
) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Authorization", "Token "+auth_token);
return params;
}
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("pk", item_id);
int quantity = Integer.parseInt(item.getNo_cart());
String quan = String.valueOf(quantity-1);
params.put("quantity",quan);
return params;
}
};
queue.add(postRequest);
}
}
});
//cart minus ends here
//-----------------------------------------------------------------------------
}
@Override
public int getItemCount() {
return list.size();
}
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView title_cart, no_cart, price_cart;
ImageView vegnon_cart;
Button btn_minus_cart, btn_plus_cart;
public MyViewHolder(@NonNull View itemView) {
super(itemView);
vegnon_cart = (ImageView)itemView.findViewById(R.id.vegnon_cart);
title_cart = (TextView)itemView.findViewById(R.id.title_cart);
no_cart = (TextView)itemView.findViewById(R.id.no_cart);
price_cart = (TextView)itemView.findViewById(R.id.price_cart);
//Button
btn_minus_cart = (Button) itemView.findViewById(R.id.btn_minus_cart);
btn_plus_cart = (Button) itemView.findViewById(R.id.btn_plus_cart);
}
@Override
public void onClick(View view) {
}
}
}
我尝试使用notiftDataSetChanged（），但是没有用。它没有在运行时更新recyclerview。我必须再次刷新页面。 我想在单击我的recyclerview行中的加号按钮后立即更新recyclerview。
答案 0 :(得分：1)
您可以做类似的事情
public void updateData( List<CartItem> newData)
{
list.clear();
list.addAll(newData);
this.notiftDataSetChanged( );
}
或使用set功能仅更新一项
public void updateOnlyOneItem(CartItem newItem,int position){
this.list.set(position, newItem);
this.notifyItemChanged();
}
答案 1 :(得分：0)
问题可能是您单击加号或减号按钮时没有更新基数列表。例如，
final CartItem item = list.get(i);
viewHolder.btn_plus_cart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
int count = item.getNo_cart()+1; //may be you can use response from network
item.setNo_cart(count); //update item
notifyDataSetChanged();
}
}
在调用notifyDataSetChanged（）之前，您需要使用新数据更新carditem对象