Xamarin.Android迁移.NET8后Google Play内购3天自动退款问题排查

原本使用Xamarin.Android开发应用，使用Plugin.InAppBilling库。迁移至.NET 8后，用户支付几天后订单会被自动退款，损失销量。了解到需要确认支付后添加了一段代码，但未生效，代码如下：

const string PRODUCT_ID = "my.product.com";
const string PRODUCT_ID_MORE_THAN_ONE= "my.other.product.com";
readonly Context context = Application.Context;

public async Task<bool> ShowDonate(bool isMoreThanOneAllowed = false)
{
    try
    {
        var connected = await CrossInAppBilling.Current.ConnectAsync();

        //Couldn't connect to billing, could be offline, alert user
        if (!connected)
        {
            Toast.MakeText(context, "No internet available", ToastLength.Short).Show();
            return false;
        }

        var productId = isMoreThanOneAllowed ? PRODUCT_ID_MORE_THAN_ONE : PRODUCT_ID;
        var purchase = await CrossInAppBilling.Current.PurchaseAsync(productId, ItemType.InAppPurchase);
        if (purchase == null)
        {
            //Not purchased, alert the user
            Toast.MakeText(context, "Didn't work", ToastLength.Short).Show();
            return false;
        }
        else
        {
            // Purchase was successful
            if ((bool)!purchase.IsAcknowledged)
            {
                if (isMoreThanOneAllowed)
                {
                    // For consumables, we need to consume the purchase
                    var consumeResult = await CrossInAppBilling.Current.ConsumePurchaseAsync(productId, purchase.PurchaseToken);
                    if (consumeResult)
                    {
                        // Consuming was successful
                        Toast.MakeText(context, "Thank you", ToastLength.Short).Show();
                        return true;
                    }
                    else
                    {
                        Toast.MakeText(context, "Didn't work", ToastLength.Short).Show();
                        return false;
                    }
                }
                else
                {
                    // For non-consumables, we finalize (acknowledge) the purchase
                    var acknowledgeResult = await CrossInAppBilling.Current.FinalizePurchaseAsync(purchase.PurchaseToken);
                    if (acknowledgeResult.First().Success)
                    {
                        Toast.MakeText(context, "Thank you", ToastLength.Short).Show();
                        return true;
                    }
                    else
                    {
                        Toast.MakeText(context, "Didn't work", ToastLength.Short).Show();
                        return false;
                    }
                }
            }
            else
            {
                // Purchase was already acknowledged
                Toast.MakeText(context, "Thank you", ToastLength.Short).Show();
                return true;
            }
        }
    }
    catch
    {
        // Handle exception
        Toast.MakeText(context, "Didn't work", ToastLength.Short).Show();
        return false;
    }
    finally
    {
        await CrossInAppBilling.Current.DisconnectAsync();
    }
}

你的代码遗漏的核心问题 #

• 未处理历史未确认/未消耗的订单
  代码只处理了当前发起购买后的确认逻辑，但如果用户购买时网络中断、APP崩溃，或者之前版本没有确认逻辑，这些历史遗留的未确认订单会触发自动退款。必须在APP启动时（或进入支付页面时）查询所有未完成的购买并批量处理：

  // 示例：查询并处理历史未确认订单
  var purchases = await CrossInAppBilling.Current.GetPurchasesAsync(ItemType.InAppPurchase);
  foreach (var purchase in purchases)
  {
      if (!purchase.IsAcknowledged)
      {
          bool isConsumable = purchase.ProductId == PRODUCT_ID_MORE_THAN_ONE;
          if (isConsumable)
          {
              await CrossInAppBilling.Current.ConsumePurchaseAsync(purchase.ProductId, purchase.PurchaseToken);
          }
          else
          {
              await CrossInAppBilling.Current.FinalizePurchaseAsync(purchase.PurchaseToken);
          }
      }
  }
  

• FinalizePurchaseAsync的使用错误
  调用acknowledgeResult.First().Success存在逻辑问题：FinalizePurchaseAsync返回的是所有确认请求的结果集合，对于单个订单的确认，应该检查所有结果是否成功，而非只取第一个：

  var acknowledgeResults = await CrossInAppBilling.Current.FinalizePurchaseAsync(purchase.PurchaseToken);
  bool allSuccess = acknowledgeResults.All(r => r.Success);
  if (allSuccess)
  {
      Toast.MakeText(context, "Thank you", ToastLength.Short).Show();
      return true;
  }
  

  另外，确认操作必须具备重试机制——即使APP退出，下次启动也要重新处理未确认的订单，不能依赖单次购买流程中的调用。

• 异常处理过于笼统
  无差别捕获所有异常会掩盖确认/消耗操作中的具体问题（比如Google Play服务错误、网络超时），无法定位故障原因。应该捕获具体异常并记录日志：

  catch (InAppBillingException billingEx)
  {
      // 记录计费异常日志
      Toast.MakeText(context, $"支付错误: {billingEx.Message}", ToastLength.Short).Show();
      return false;
  }
  catch (Exception ex)
  {
      // 记录其他异常日志
      Toast.MakeText(context, "操作失败", ToastLength.Short).Show();
      return false;
  }
  

• 产品类型配置与代码逻辑不匹配
  必须确保PRODUCT_ID_MORE_THAN_ONE在Google Play控制台中标记为消耗品，PRODUCT_ID标记为非消耗品。如果类型配置错误，消耗/确认操作会失败，导致订单无法完成，触发自动退款。

• ConnectAsync参数缺失
  在.NET 8环境下，Plugin.InAppBilling的ConnectAsync可能需要传入指定Google Play Billing版本的参数，确保你使用的是最新版本的NuGet包，并按照官方文档正确调用连接方法。

内容的提问来源于stack exchange，提问作者Federico Navarrete