我想计算 List 中物品的价格并将值存储在sharedpreference. 每个项目都有一个采用双精度形式的价格。问题是当我使用我的方法时，它只考虑列表中的一个项目并计算该值。我正在使用 aNumberPicker来更改项目的数量。
这是我的适配器，用于处理将显示在 上的项目列表RecyclerView：
public class CartAdapter extends RecyclerView.Adapter<CartAdapter.ViewHolder> {
private List<SingleItem> items;
private SessionManager sessionManager;
private Context context;
private int pos;
public CartAdapter() {
}
public CartAdapter(Context context, List<SingleItem> items) {
this.items = items;
this.context = context;
sessionManager = new SessionManager(context);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cartitem, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
final SingleItem singleItem = items.get(position);
holder.tv_title.setText(singleItem.getTitle());
holder.tv_price.setText("Ksh: " + singleItem.getPrice());
Picasso.with(context).load(singleItem.getUrl()).fit().into(holder.imgcart);
holder.numcart.setMinValue(1);
holder.numcart.setMaxValue(15);
holder.numcart.setWrapSelectorWheel(false);
int qty = holder.numcart.getValue();
getTotal(qty, singleItem.getPrice());
}
public double getTotal(int value, double amount){
double totalamount;
double amountall = amount;
int quantity = value;
totalamount = amountall * quantity;
sessionManager.grandtotal("Ksh: " + totalamount);
return totalamount;
}
@Override
public int getItemCount() {
return items.size();
}
public void removeItem(SingleItem item) {
sessionManager.removeitem(context,item);
items.remove(item);
notifyDataSetChanged();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView tv_price;
TextView tv_title;
NumberPicker numcart;
ImageView imgcart;
public ViewHolder(View view) {
super(view);
tv_price = (TextView) view.findViewById(R.id.titlecart);
tv_title = (TextView) view.findViewById(R.id.pricecart);
numcart = (NumberPicker) view.findViewById(R.id.pickercart);
imgcart = (ImageView) view.findViewById(R.id.imgcart);
}
}
}
这是我在片段上显示 RecyclerView 的方式：
public class Details extends Fragment {
private RecyclerView RecyclerDetails;
private TextView CartPrice;
private CheckBox CheckCart;
private List<SingleItem> list;
private CartAdapter adapter;
private boolean add = false;
private Paint p = new Paint();
private SessionManager sessionManager;
private int pos;
public Details() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_details, container, false);
RecyclerDetails = (RecyclerView) view.findViewById(R.id.recyclercart);
CartPrice = (TextView) view.findViewById(R.id.tvcarttotal);
CheckCart = (CheckBox) view.findViewById(R.id.chkcart);
sessionManager = new SessionManager(getContext());
Toasty.info(getContext(),"Swipe to go to Next", Toast.LENGTH_SHORT,true).show();
RecyclerDetails.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
RecyclerDetails.setLayoutManager(layoutManager);
list = sessionManager.getItems(getContext());
HashMap<String,String> map = sessionManager.itemstostring();
String data = map.get(SessionManager.KEY_ITEMS);
Log.i(Constants.TAG,data);
HashMap<String,String> tot = sessionManager.getgrandtotal();
String total = tot.get(SessionManager.KEY_TOTAL);
CartPrice.setText(total);
CheckCart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (((CheckBox) v).isChecked()){
sessionManager.saveditems("true");
} else {
sessionManager.saveditems("false");
}
}
});
RecyclerDetails.addOnItemTouchListener(new RecyclerItemClickListener(getContext(), new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
}));
if(list != null){
adapter = new CartAdapter(getContext(),list);
RecyclerDetails.setAdapter(adapter);
}
initswipe();
return view;
}
private void initswipe() {
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();
if (direction == ItemTouchHelper.RIGHT) {
adapter.removeItem(list.get(position));
sessionManager.saveitems(getContext(),list);
}
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
Bitmap icon;
if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE){
View itemView = viewHolder.itemView;
float height = (float) itemView.getBottom() - (float) itemView.getTop();
float width = height / 3;
if(dX > 0){
p.setColor(Color.parseColor("#14a895"));
RectF background = new RectF((float) itemView.getLeft(), (float) itemView.getTop(), dX,(float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(getResources(), android.R.drawable.ic_menu_delete);
RectF icon_dest = new RectF((float) itemView.getLeft() + width ,(float) itemView.getTop() + width,(float) itemView.getLeft()+ 2*width,(float)itemView.getBottom() - width);
c.drawBitmap(icon,null,icon_dest,p);
} else {
p.setColor(Color.parseColor("#14a895"));
RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(),(float) itemView.getRight(), (float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(getResources(),android.R.drawable.ic_menu_delete);
RectF icon_dest = new RectF((float) itemView.getRight() - 2*width ,(float) itemView.getTop() + width,(float) itemView.getRight() - width,(float)itemView.getBottom() - width);
c.drawBitmap(icon,null,icon_dest,p);
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(RecyclerDetails);
}
}
最后，这是我用来存储列表中所有项目总和的函数
public void grandtotal (String total){
editor.putString(KEY_TOTAL,total);
editor.commit();
}
public HashMap<String, String> getgrandtotal(){
HashMap<String, String> tot = new HashMap<>();
tot.put(KEY_TOTAL,pref.getString(KEY_TOTAL,null));
return tot;
}
是否有我没有包含在我RecyclerView与项目一起显示的片段中的功能？
只是需要一个小的改变吗？
private int grandTotal(List<SingleItem> items){
int totalPrice = 0;
for(int i = 0 ; i < items.size(); i++) {
totalPrice += items.get(i).getPrice();
}
return totalPrice;
}
这是您需要实施以获得总价的方法。您可以在添加项目或从列表中删除项目时调用此方法。
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我来说两句