main.dart

  Future _getProduct() async {
    List<IAPItem> items =
        await FlutterInappPurchase.instance.getProducts(_productLists);
    for (var item in items) {
      print('${item.toString()}');
      this._items.add(item);
    }

    setState(() {
      this._items = items;
      this._purchases = [];
    });
  }

  Future _getPurchases() async {
    List<PurchasedItem> items =
        await FlutterInappPurchase.instance.getAvailablePurchases();
    for (var item in items) {
      print('${item.toString()}');
      this._purchases.add(item);
    }

    setState(() {
      this._items = [];
      this._purchases = items;
    });
  }