Flutter in_app_purchase插件iOS恢复购买先识别为新购买的问题咨询

原因分析 #

iOS App Store的内购恢复机制和Android存在本质差异：当调用restorePurchases()时，系统会先将已购买的非消耗品交易以PurchaseStatus.purchased状态推送给观察者，随后再将这些交易更新为PurchaseStatus.restored状态。这是iOS平台的原生行为，in_app_purchase插件只是如实转发了系统的状态变化事件，因此会出现先收到purchased再收到restored的情况。

同时你的代码存在两个放大问题的细节：

• 在处理purchased状态时调用了completePurchase()，这会让iOS系统误判该交易为主动完成的购买，干扰后续恢复状态的推送逻辑。
• 未区分主动购买和恢复操作的事件流，导致两种场景的状态被无差别处理，引发重复逻辑执行。

解决方案 #

1. 增加恢复状态标记，区分事件场景 #

在类中添加布尔变量标记当前是否处于恢复流程，调用restorePurchases()时设为true，恢复完成后重置为false，以此跳过恢复流程中的purchased状态处理：

bool _isRestoring = false;

// 恢复购买的方法
Future<void> restorePurchases() async {
  _isRestoring = true;
  await iap.restorePurchases();
  // 恢复完成后重置标记
  _isRestoring = false;
}

Future<void> listenForPurchases() async {
  print("Called listenForPurchases method");
  iap.purchaseStream.listen((List<PurchaseDetails> purchases) async {
    print("Listened");
    bool purchaseStatus = await purchaseProducts().handlePurchase(purchases);
    if (purchaseStatus == true) {
      for (var purchase in purchases) {
        print("User has ${purchase.status.toString()} ${purchase.productID}");
        if (purchase.status == PurchaseStatus.purchased) {
          // 仅在非恢复流程时处理主动购买逻辑
          if (!_isRestoring) {
            print("NEW Purchase was made");
            // 执行主动购买的业务逻辑
            await iap.completePurchase(purchase);
          }
        } else if (purchase.status == PurchaseStatus.restored) {
          print("Restore was made");
          // 执行恢复购买的业务逻辑
          // iOS恢复的交易无需调用completePurchase，系统会自动处理
        }
      }
    }
  });
}

2. 避免在恢复流程中调用completePurchase #

iOS平台的恢复交易由系统自动完成收尾操作，只有用户主动发起的购买才需要手动调用completePurchase()确认交易完成。

3. 过滤重复交易事件 #

通过PurchaseDetails的transactionID过滤已处理过的交易，避免因状态重复推送导致逻辑重复执行：

final Set<String> _processedTransactionIds = {};

Future<void> listenForPurchases() async {
  print("Called listenForPurchases method");
  iap.purchaseStream.listen((List<PurchaseDetails> purchases) async {
    print("Listened");
    bool purchaseStatus = await purchaseProducts().handlePurchase(purchases);
    if (purchaseStatus == true) {
      for (var purchase in purchases) {
        // 跳过已处理的交易
        if (_processedTransactionIds.contains(purchase.transactionID)) continue;
        
        print("User has ${purchase.status.toString()} ${purchase.productID}");
        if (purchase.status == PurchaseStatus.purchased) {
          if (!_isRestoring) {
            print("NEW Purchase was made");
            // 业务逻辑
            await iap.completePurchase(purchase);
            _processedTransactionIds.add(purchase.transactionID!);
          }
        } else if (purchase.status == PurchaseStatus.restored) {
          print("Restore was made");
          // 业务逻辑
          _processedTransactionIds.add(purchase.transactionID!);
        }
      }
    }
  });
}

内容的提问来源于stack exchange，提问作者jscodes