android - 如何从recyclerview获取整数值的总和

Question

我想实现发票之类的东西。我在 fragment 中使用 recyclerview。和 TextView 。我在 recyclerview 中有一些项目。内容标题、单位和价格。现在我想在我的 TextView 中获取所有项目价格的总和，它是 fragment 的。这是我想要实现的图像。

这里是理解的图像

这是我的适配器类代码

public class Checkout_fragment2_confermation_Adapter extends RecyclerView.Adapter<Checkout_fragment2_confermation_Adapter.ViewHolder>  {

static List<Cart_datamodel> data;
static Context context;

public Checkout_fragment2_confermation_Adapter(Context context , List<Cart_datamodel> data1) {
    data = new ArrayList<Cart_datamodel>();
    this.context = context;
    this.data = data1;
}


@Override
public Checkout_fragment2_confermation_Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    final View itemLayoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.checkout_fragmet2confermation_listviwe_single_row, null);
    itemLayoutView.setLayoutParams(new RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT));
    Checkout_fragment2_confermation_Adapter.ViewHolder viewHolder = new Checkout_fragment2_confermation_Adapter.ViewHolder(itemLayoutView);

    return viewHolder;
}

@Override
public void onBindViewHolder(Checkout_fragment2_confermation_Adapter.ViewHolder holder, int position) {

    holder.title.setText(data.get(position).getTitle());
    holder.price.setText(data.get(position).getPrice());
    holder.product_img.setImageBitmap(getImage(data.get(position).getImg()));


}

@Override
public int getItemCount() {
    return data.size();
}

public class ViewHolder extends RecyclerView.ViewHolder {
    public TextView  title,price;
    public ImageView img,product_img;

    public ViewHolder(View itemView) {
        super(itemView);
        title = (TextView)itemView.findViewById(R.id.title_checkout_fgment2);
        price =(TextView)itemView.findViewById(R.id.price_checkout_fragment2);
        product_img =(ImageView)itemView.findViewById(R.id.image_checkout_fragment2);
    }
}
public static Bitmap getImage(byte[] image) {
    return BitmapFactory.decodeByteArray(image, 0, image.length);
}

}

这是我的 fragment 类

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.fragmenttab2, container, false);

    dataBaseAdapter = new AddressDataBaseAdapter(getContext());
    cart_adapter = new Item_adding_cart(getContext());
    dbList = cart_adapter.getDataFromDB();

   // listview = (ListView)view.findViewById(R.id.listview);

    recyclerView =(RecyclerView)view.findViewById(R.id.my_recycler_view_checkout_fgrment2);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
    recycleradapter = new Checkout_fragment2_confermation_Adapter(getContext(),dbList);
    recyclerView.setAdapter(recycleradapter);



    fname =(TextView)view.findViewById(R.id.firstname_conformation);
    lname =(TextView)view.findViewById(R.id.lastname_conformation);
    mobile =(TextView)view.findViewById(R.id.mobile_conformaton);
    address =(TextView)view.findViewById(R.id.address_conformation);
    zipcode =(TextView)view.findViewById(R.id.zipcode_conformation);
    city =(TextView)view.findViewById(R.id.city_conformation);




    addresslist= new ArrayList<Address_Activity_DataModel>();
    addresslist=dataBaseAdapter.getDataFromDB();

    int count = dataBaseAdapter.getrowcount();
    if(count==0){

    }
    else
    {
        showRecords();
    }

   // loaddata();



    return view;

}

Answer 1

只需计算您的 recyclerview 列表的数量并乘以该值即可得到完美的总和，即 fragment

List<ItemPurchase> item = new ArrayList<>();             
int total = 0;
for(int i = 0; i < items.size; i++){
    total = total + items.get(i).price()}

 t.setText(String.valueOf( total));

kotlin中的这个函数

var total = 0;
            for ( i in 0 until  myDebt.size){
                total += myDebt[i].valueAdp
            }

这是获取总价所需实现的方法。可以在您的 Activity 中调用此方法并且您仍然可以将该值分配给 textView。

 mtv_my_debt.setText(String.valueOf(total))