我正在开发一个应用程序，该应用程序在包含菜单项的片段中包含recyclerviewA，在另一个recyclerviewB中选择另一个recyclerviewB作为购物车。当在recyclerA中选择一个项目时，可以使用在recyclerviewB中更新的相同项目的每个项目行上的2个按钮（用于添加和删除项目）来增加或减少其编号。如果项目编号减少到零0，则该项目将从recyclerviewB中删除。当在recyclerviewA中为每个项目使用加或减按钮时，这很有效。在减少recyclerviewB中所选项目的数量时会出现问题。在从上到下移除第一个项目后，项目位置不会更新。例如，当项目0被移除时，项目1保留在项目1而不是将其更新到项目0所以adapterPosition为0，因此返回该位置的空项。从下往上删除项目时我没有这个问题。
适用于RecyclerviewA的Adadpater
public class MenuListAdapter extends RecyclerView.Adapter<MenuListAdapter.menuListViewHolder> {
Context mContext;
private static final int min = 0;
boolean refreshList;
private RequestManager mGlide;
List<MenuItem> mItems;
class menuListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
CardView cv;
TextView item_name;
TextView item_desc;
TextView price;
TextView num_orders;
TextView text_number;
ImageView item_image;
Button btn_add;
Button btn_subtract;
RelativeLayout rl_item;
private menuListViewHolder(View itemView) {
super(itemView);
cv = (CardView)itemView.findViewById(R.id.menulistcv);
item_name = (TextView)itemView.findViewById(R.id.item_name);
item_desc = (TextView)itemView.findViewById(R.id.item_desc);
price = (TextView)itemView.findViewById(R.id.item_price);
num_orders = (TextView)itemView.findViewById(R.id.item_count);
item_image = (ImageView)itemView.findViewById(R.id.iv_food);
btn_add =(Button) itemView.findViewById(R.id.btn_add);
btn_subtract =(Button) itemView.findViewById(R.id.btn_subtract);
text_number = (TextView)itemView.findViewById(R.id.text_number);
rl_item= (RelativeLayout) itemView.findViewById(R.id.item_top);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
}
}
public MenuListAdapter(List<MenuItem> menuItems) {
mItems= menuItems;
}
public MenuListAdapter(Context context , List<MenuItem> menuItems) {
mItems= menuItems;
mContext= context;
}
public MenuListAdapter(RequestManager glide, List<MenuItem> menuItems) {
mGlide = glide;
mItems= menuItems;
}
public MenuListAdapter() {
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
@Override
public MenuListAdapter.menuListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.menu_list_item, parent, false);
// set the view's size, margins, paddings and layout parameters
MenuListAdapter.menuListViewHolder vh = new MenuListAdapter.menuListViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(final menuListViewHolder vholder, int position) {
vholder.item_name.setText(mItems.get(vholder.getAdapterPosition()).getItem_Name());
vholder.item_desc.setText(mItems.get(vholder.getAdapterPosition()).getDescription());
vholder.price.setText("$" + String.valueOf(mItems.get(vholder.getAdapterPosition()).getPrice()));
vholder.text_number.setText(String.valueOf(mItems.get(vholder.getAdapterPosition()).getNum()));
Log.i("yo",String.valueOf(mItems.get(vholder.getAdapterPosition()).getItem_Name()));
if(mItems.get(vholder.getAdapterPosition()).getItem_Image() == null){
mGlide.load(R.drawable.logo)
.into(vholder.item_image);
}
else {
mGlide.load((mItems.get(vholder.getAdapterPosition()).getItem_Image()))
.into(vholder.item_image);
}
vholder.btn_add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mOnItemClickLister.handlerCarNum(vholder.getAdapterPosition(),1,mItems.get(vholder.getAdapterPosition()),true);
}
});
vholder.btn_subtract.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mOnItemClickLister.handlerCarNum(vholder.getAdapterPosition(),0,mItems.get(vholder.getAdapterPosition()),true);
}
});
vholder.rl_item.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Toast.makeText(view.getContext(), "Selected", Toast.LENGTH_SHORT).show();
}
});
}
@Override
public int getItemCount() {
return mItems.size();
}
private static ModifyItem mOnItemClickLister;
public interface ModifyItem{
void handlerCarNum(int position,int type, MenuItem menuItem, boolean refreshList);
}
public void setOnItemClickListener(ModifyItem listener) {
mOnItemClickLister = listener;
}
}
RecyclerviewB适配器
public class SelectedProductAdapter extends RecyclerView.Adapter<SelectedProductAdapter.selectedListViewHolder> {
Context mContext;
MenuListAdapter mMenuListAdapter;
CategoryListAdapter categoryListAdapter;
SparseArray<MenuItem> mItems;
List<MenuItem> mnItems;
private static final int min = 0;
boolean refreshList;
public SelectedProductAdapter(Context context, SparseArray<MenuItem> menuItems) {
mContext = context;
mItems = menuItems;
}
public SelectedProductAdapter(Context context, SparseArray<MenuItem> menuItems, MenuListAdapter menuListAdapter) {
mContext = context;
mMenuListAdapter = menuListAdapter;
mItems = menuItems;
}
public SelectedProductAdapter() {
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
@Override
public SelectedProductAdapter.selectedListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.cart_item, parent, false);
// set the view's size, margins, paddings and layout parameters
SelectedProductAdapter.selectedListViewHolder vh = new SelectedProductAdapter.selectedListViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(final selectedListViewHolder vholder, final int position) {
vholder.tv_name.setText(mItems.valueAt(vholder.getAdapterPosition()).getItem_Name()+ " " + mItems.valueAt(vholder.getAdapterPosition()).getDescription());
vholder.tv_price.setText("$" + String.valueOf(mItems.valueAt(vholder.getAdapterPosition()).getPrice()));
vholder.tv_count.setText(String.valueOf(mItems.valueAt(vholder.getAdapterPosition()).getNum()));
vholder.btn_add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mOnItemClickLister.handlerCarNum(vholder.getAdapterPosition(),1,mItems.valueAt(vholder.getAdapterPosition()),true);
}
});
vholder.btn_subtract.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mOnItemClickLister.handlerCarNum(vholder.getAdapterPosition(),0,mItems.valueAt(vholder.getAdapterPosition()),true);
}
});
}
@Override
public int getItemCount() {
return mItems.size();
}
public Object getItem(int position) {
return mItems.valueAt(position);
}
class selectedListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView tv_price;
TextView tv_name;
Button btn_add,btn_subtract;
TextView tv_count;
public selectedListViewHolder(View itemView) {
super(itemView);
tv_name = (TextView) itemView.findViewById(R.id.tv_name);
tv_price = (TextView) itemView.findViewById(R.id.tv_price);
btn_add= (Button) itemView.findViewById(R.id.btn_add);
btn_subtract= (Button) itemView.findViewById(R.id.btn_subtract);
tv_count= (TextView) itemView.findViewById(R.id.tv_count);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
}
}
private static CartItemInterface mOnItemClickLister;
public interface CartItemInterface{
void handlerCarNum(int position,int type, MenuItem menuItem, boolean refreshList);
}
public void setOnItemClickListener(CartItemInterface listener) {
mOnItemClickLister = listener;
}
片段/界面添加和删除项目的方法
//interface method to add items to cart
@Override
public void handlerCarNum(int position,int type, MenuItem menuItem, boolean refreshList){
if (type == 0) {
MenuItem temp = cartItems.get(position);
if(temp!=null) {
if (temp == menuItem) {
if (temp.getNum() < 2) {
menuItem.setNum(0);
cartItems.remove(position);
selectedProductAdapter.notifyItemRemoved(position);
selectedProductAdapter.notifyItemRangeChanged(position,cartItems.size());
selectedProductAdapter.notifyDataSetChanged();
} else {
int i = menuItem.getNum();
menuItem.setNum(--i);
}
}
}
} else if (type == 1) {
MenuItem temp = cartItems.get(position);
if(temp==null){
menuItem.setNum(1);
cartItems.append(position, menuItem);
}else{
int i= menuItem.getNum();
menuItem.setNum(++i);
}
}
update(refreshList);
}
//update items when dataset changes
@Override
public void update(boolean refreshGoodList){
if(selectedProductAdapter!=null){
selectedProductAdapter.notifyDataSetChanged();
}
if(menuListAdapter!=null){
menuListAdapter.notifyDataSetChanged();
}
if(bottomSheetLayout.isSheetShowing() && cartItems.size()<1){
bottomSheetLayout.dismissSheet();
}
}