Java 从Recyclerview适配器类更新textview
我正在开发一个电子商务应用程序来下一些在线订单。在my Recyclerview中，有在上一个活动中添加的产品。在这里，我用诸如商品名称、数量、价格等详细信息填充Recyclerview中添加的产品。。有用于增加/减少每个产品数量的按钮，还有一个用于删除项目的按钮 在Recyclerview布局的底部，有另一个文本视图显示总计。当我处理RecycleServiceAdapter类中的按钮滑动时，当用户更新数量或删除项目时，我必须更新总计。我尝试了这里已经提到的一些解决方案，但是应用程序在随机点击按钮时崩溃。请提供解决方案或更好的方法 以下是我的适配器类：Java 从Recyclerview适配器类更新textview,java,android,android-recyclerview,e-commerce,Java,Android,Android Recyclerview,E Commerce,我正在开发一个电子商务应用程序来下一些在线订单。在my Recyclerview中，有在上一个活动中添加的产品。在这里，我用诸如商品名称、数量、价格等详细信息填充Recyclerview中添加的产品。。有用于增加/减少每个产品数量的按钮，还有一个用于删除项目的按钮 在Recyclerview布局的底部，有另一个文本视图显示总计。当我处理RecycleServiceAdapter类中的按钮滑动时，当用户更新数量或删除项目时，我必须更新总计。我尝试了这里已经提到的一些解决方案，但是应用程序在随机点击
public class InvoiceRecyclerViewAdapter extends RecyclerView.Adapter<InvoiceRecyclerViewAdapter.ViewHolder> {
private static final String TAG = "RecylerViewAdapter";
List<Products> addedProductsList;
Context mContext;
public InvoiceRecyclerViewAdapter(Context mContext,List<Products> addedProductsList)
{
this.mContext=mContext;
this.addedProductsList=addedProductsList;
}
public InvoiceRecyclerViewAdapter(Context mContext)
{
this.mContext=mContext;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_invoice,parent,false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
holder.item_qty.setText("1");
holder.itemname.setText(addedProductsList.get(position).getName());
holder.itemprice.setText("Rs "+addedProductsList.get(position).getPrice());
holder.itemdiscount.setText("Rs "+calculate_dis(position));
holder.itemtotal.setText("Rs "+calculate_total(position));
holder.button_inc.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int qty = addedProductsList.get(position).getQty();
qty++;
addedProductsList.get(position).setQty(qty);
holder.item_qty.setText(""+qty);
holder.itemdiscount.setText("Rs "+calculate_dis(position));
holder.itemtotal.setText("Rs "+calculate_total(position));
UpdateTotal();
}
});
holder.button_dec.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int qty = addedProductsList.get(position).getQty();
qty--;
if(qty>0){
addedProductsList.get(position).setQty(qty);
holder.item_qty.setText(""+qty);
holder.itemdiscount.setText("Rs"+calculate_dis(position));
holder.itemtotal.setText("Rs"+calculate_total(position));
UpdateTotal();
}
}
});
holder.button_cancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
addedProductsList.get(position).setAddedTocart(false);
//notifyDataSetChanged();
addedProductsList.remove(position);
notifyItemRemoved(position);
UpdateTotal();
}
});
}
@Override
public int getItemCount() {
return addedProductsList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
TextView itemname,itemtotal,itemprice,itemdiscount,item_qty;
Button button_cancel,button_inc,button_dec;
ConstraintLayout parent_layout;
public ViewHolder(View itemView) {
super(itemView);
itemname = itemView.findViewById(R.id.textView_item_name);
itemprice = itemView.findViewById(R.id.textView_item_price);
itemdiscount = itemView.findViewById(R.id.textView_item_discount);
itemtotal = itemView.findViewById(R.id.textView_item_total);
button_cancel = itemView.findViewById(R.id.button_cancel);
button_inc=itemView.findViewById(R.id.button_inc);
button_dec=itemView.findViewById(R.id.button_dec);
item_qty = itemView.findViewById(R.id.textView_qty);
parent_layout = itemView.findViewById(R.id.invoice_parent_layout);
}
}
private float calculate_dis(int pos){
float dis = 0;
if(addedProductsList.get(pos).isPrice_g_enabled()){
int qty=addedProductsList.get(pos).getQty();
dis = Float.parseFloat(addedProductsList.get(pos).getPrice())-Float.parseFloat(addedProductsList.get(pos).getPrice_g());
dis = qty*dis;
}
return dis;
}
private float calculate_total(int pos){
int qty=addedProductsList.get(pos).getQty();
float price,total;
if(addedProductsList.get(pos).isPrice_g_enabled()){
price = Float.parseFloat(addedProductsList.get(pos).getPrice_g());
}
else{
price= Float.parseFloat(addedProductsList.get(pos).getPrice());
}
total = price*qty;
return total;
}
private void UpdateTotal(){
TextView txtView =((EditQuantity)mContext).findViewById(R.id.textView_total);
float total=0,price=0;
int qty=0;
for(int i=0;i<addedProductsList.size();i++){
if(addedProductsList.get(i).isAddedTocart()) {
qty = addedProductsList.get(i).getQty();
if(addedProductsList.get(i).isPrice_g_enabled()){
price = Float.parseFloat(addedProductsList.get(i).getPrice_g());
}
else{
price= Float.parseFloat(addedProductsList.get(i).getPrice());
}
}
total=total+(qty*price);
}
txtView.setText("Rs "+total);
}
}
for（inti=0；i我建议遍历一个侦听器，移动onclicklistener并删除for循环 所以，一步一步 在适配器类中声明一个接口
public interface OnQuantityChangeListener {
void onQuantityChange( float change );
}
private OnQuantityChangeListener mListener;
public InvoiceRecyclerViewAdapter(Context mContext,List<Products> addedProductsList, OnQuantityChangeListener listener) {
this.mContext=mContext;
this.addedProductsList=addedProductsList;
mListener = listener;
}
public InvoiceRecyclerViewAdapter(Context mContext, OnQuantityChangeListener listener)
{
this.mContext=mContext;
mListener = listener;
}
private OnQuantityChangeListener mListener;
public InvoiceRecyclerViewAdapter(Context mContext,List<Products> addedProductsList, OnQuantityChangeListener listener) {
this.mContext=mContext;
this.addedProductsList=addedProductsList;
mListener = listener;
}
public InvoiceRecyclerViewAdapter(Context mContext, OnQuantityChangeListener listener)
{
this.mContext=mContext;
mListener = listener;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_invoice,parent,false);
ViewHolder viewHolder = new ViewHolder(view);
viewHolder.button_inc.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Products product = addedProductsList.get(getAdapterPosition());
product.setQty( product.getQty() + 1 );
float difference = product.isPrice_g_enabled() ? Float.parseFloat(product.getPrice_g()) : Float.parseFloat(product.getPrice());
mListener.onQuantityChange( difference );
notifyItemChanged( getAdapterPosition ):// This will call onBindViewAdapter again and change all your strings for you
}
});
viewHolder.button_dec.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Products product = addedProductsList.get(getAdapterPosition());
if( product.getQty() == 0 )// Can't remove an item if it's already at 0
return;
product.setQty( product.getQty() - 1 );
float difference = product.isPrice_g_enabled() ? Float.parseFloat(product.getPrice_g()) : Float.parseFloat(product.getPrice());
mListener.onQuantityChange( -difference );
notifyItemChanged( getAdapterPosition ):// This will call onBindViewAdapter again and change all your strings for you
}
});
viewHolder.button_cancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Products product = addedProductsList.get(getAdapterPosition());
float difference = product.isPrice_g_enabled() ? Float.parseFloat(product.getPrice_g()) : Float.parseFloat(product.getPrice());
mListener.onQuantityChange( -difference * product.getQty() );
product.setQty( 0 );
notifyItemChanged( getAdapterPosition ):// This will call onBindViewAdapter again and change all your strings for you
// You decide at this point if you want to remove the item altogether or just show 0
}
});
return viewHolder;
}
private float total = 0;
InvoiceRecyclerViewAdapter adapter = new InvoiceRecyclerViewAdapter(
this ,cart_productslist, new InvoiceRecyclerViewAdapter.OnQuantityChangeListener(){
@Override
void onQuantityChange( float difference ){
total += difference;
total_textview.setText("Rs "+ total);
}
} );