如何將每個訂購商品存儲在Xamarin.Android的購物車列表中？

Question

試圖在Xamarin.Android中開發一個物品訂購系統。爲了顯示項目列表，我在每一行都使用了帶有自定義適配器的「購物車」按鈕。您能否建議我使用哪種技術，或者如何將每個訂購商品存儲在列表中，這些列表將進入我的購物車列表活動？ 這裏是我的itemListAdapter類：

謝謝！

My ItemList Image

namespace Test.Restaurant.Android.Adapters 
{ 
public class ItemListAdapter : BaseAdapter 
{ 
List mItems; 
Activity context; 
private OrderDetail _OrderDetails; 
private List _OrderDetailsList; 

    public ItemListAdapter(Activity context, List<Item> items) : base() 
    { 
     this.context = context; 
     this.mItems = items; 
    } 

    public override long GetItemId(int position) 
    { 
     return position; 
    } 

    public override Item this[int position] 
    { 
     get { return mItems[position]; } 
    } 

    public override int Count 
    { 
     get { return mItems.Count; } 
    } 

    public override View GetView(int position, View convertView, ViewGroup parent) 
    { 

     View view = convertView ?? context.LayoutInflater.Inflate(Resource.Layout.ItemRowView, parent, false); 
     var viewHolder = view.Tag as ItemHolder; 
     var item = mItems[position]; 
     Bitmap myImage = ImageHelper.Bytes2Bimap(item.Image); 

     // 03. List With Custom Row View   

     if (viewHolder == null) 
     { 

      viewHolder = new ItemHolder 
      { 
       itemNameTextView = view.FindViewById<TextView>(Resource.Id.itemNameTextView), 
       descriptionTextView = view.FindViewById<TextView>(Resource.Id.descriptionTextView), 
       itemImageView = view.FindViewById<ImageView>(Resource.Id.itemImageView), 
       priceTextView = view.FindViewById<TextView>(Resource.Id.priceTextView),      
       btnPlus = view.FindViewById<ImageView>(Resource.Id.btnPlus), 
       btnMinus = view.FindViewById<ImageView>(Resource.Id.btnMinus), 
       btnAddtoCart = view.FindViewById<ImageView>(Resource.Id.btnAddToCart), 
       txtQty = view.FindViewById<TextView>(Resource.Id.cart_product_quantity) 
      }; 
      view.Tag = viewHolder; 
     } 
     else 
     { 
      viewHolder = view.Tag as ItemHolder; 
     } 


     viewHolder.itemNameTextView.Text = item.ItemName; 
     viewHolder.descriptionTextView.Text = item.ItemDescription; 
     viewHolder.priceTextView.Text = "$ " + 30; 
     viewHolder.itemImageView.SetImageBitmap(myImage); 


     if (!viewHolder.btnAddtoCart.HasOnClickListeners) 
     { 

      viewHolder.btnAddtoCart.Click += (sender, args) => 
      { 

       _OrderDetails = new OrderDetail(); 
       _OrderDetails.ItemId = item.ItemId; 
       _OrderDetails.Quantity = int.Parse(viewHolder.txtQty.Text); 
       _OrderDetails.UnitPriceInclTax = 0; 
       _OrderDetails.UnitPriceExclTax = 0; 
       _OrderDetails.DiscountAmountInclTax = 0; 
       _OrderDetails.DiscountAmountExclTax = 0; 
       _OrderDetails.PriceInclTax = 100; 
       _OrderDetails.PriceExclTax = 0; 


      ** //What should I Do Here???** 

     ************************** 
     ************************** 
      }; 
     } 

     return view; 

    } 


    private class ItemHolder : Java.Lang.Object 
    { 
     public TextView itemNameTextView { get; set; } 
     public TextView descriptionTextView { get; set; } 
     public TextView txtQty { get; set; } 
     public ImageView itemImageView { get; set; } 
     public ImageView btnPlus { get; set; } 
     public ImageView btnMinus { get; set; } 
     public ImageView btnAddtoCart { get; set; } 
    } 
} 
} 

Answer 1

能否請你給我建議，我應該使用哪種技術或我怎麼能存儲在其中會去我的車列表活動列表中的每個訂購的商品？

你需要一個CartLilst（List<OrderDetail>）傳遞給你的適配器：

public class ItemListAdapter : BaseAdapter 
{ 
    ... 
    List<OrderDetail> cartList; 

    public ItemListAdapter(Activity context, List<Item> items, List<OrderDetail> cartList) 
    { 
     this.context = context; 
     this.mItems = items; 
     _cartlist = cartList; 
    } 
    ... 
} 

而當用戶點擊addToCart按鈕時，的OrderDetail添加到這個列表：

viewHolder.btnAddtoCart.Click += (sender, args) => 
{ 

    _OrderDetails = new OrderDetail(); 
    _OrderDetails.ItemId = item.ItemId; 
    _OrderDetails.Quantity = int.Parse(viewHolder.txtQty.Text); 
    _OrderDetails.UnitPriceInclTax = 0; 
    _OrderDetails.UnitPriceExclTax = 0; 
    _OrderDetails.DiscountAmountInclTax = 0; 
    _OrderDetails.DiscountAmountExclTax = 0; 
    _OrderDetails.PriceInclTax = 100; 
    _OrderDetails.PriceExclTax = 0; 


    //add _OrderDetail to cartList 
    cartList.Add(_OrderDetails); 
}; 

清單應在適配器創建之前在您的Activity中進行初始化和創建：

List<OrderDetail> cartList=new List<OrderDetail>(); 
ItemListAdapter adapter=new ItemListAdapter(this,items,cartList); 

更新：

如果使用您的購物車清單經常在你的應用程序，那麼我建議你忘了我說的話，用一個模式來存儲您的應用內購物車清單：

1. 在您的應用程序創建一個CartList.cs：

   public class CartList 
   { 
       private static List<OrderDetail> _cartList; 
       public static List<OrderDetail> Instance 
       { 
        get 
        { 
         if (_cartList == null) 
         { 
          _cartList = new List<OrderDetail>(); 
         } 
         return _cartList; 
        } 
        set 
        { 
         _cartList = value; 
        } 
       } 
   } 
   

2. 然後你就可以在你的應用程序在任何地方使用這個CartList（你不需要將它傳遞到y我們的新的活動，你可以在你的新的活動直接得到它）：

   var cartList=CartList.Instance;