Question

我不知道这里缺少什么。.这是一个假定可以向客户下订单的功能。整个逻辑非常简单：

如果购物车中有1个单项，则只需执行一次。如果还有更多，请将订单附加到第一个订单号上。但是由于某种原因，它不等到orderRepo.addOrder执行开始时就结束。

  dynamic firstOrderNumber = 0;
  var existingOrder = false;

  void addOrder(List<Cart> carts) async {        --> Coming to add the list of orders
    carts.forEach((_cart) async {                --> Going to add each items in cart
      
             x += 1;
  print("\nVALUE of x inside addOrder = $x");     -> Adding X flag here to check
      Order _order = new Order();

      _order.productOrders = new List<ProductOrder>();
      _order.tax = _cart.product.store.defaultTax;
      _order.deliveryFee = payment.method == 'Pay on Pickup'
          ? 0
          : _cart.product.store.deliveryFee;
      OrderStatus _orderStatus = new OrderStatus();
      _orderStatus.id = '1'; 
      _order.orderStatus = _orderStatus;
      _order.deliveryAddress = payment.method == 'Pay on Pickup'
          ? new Address()
          : settingRepo.deliveryAddress.value;
      _order.hint = ' ';
      ProductOrder _productOrder = new ProductOrder();
      _productOrder.quantity = _cart.quantity;
      _productOrder.price = _cart.product.price;
      _productOrder.id = _cart.product.id;
      _productOrder.product = _cart.product;
      _productOrder.options = _cart.options;

      _order.productOrders.add(_productOrder);
      print("Current value of EXISTING : $existingOrder");
      if (!existingOrder) {
        print("\n\nEntering not existing order....\n");
        await orderRepo.addOrder(_order, this.payment).then((value) {      ---> Doesn't wait. PROBLEM
          if (value is Order) {
            print("The value is now $value");
            firstOrderNumber =
                value.id.toString(); //catching order number to append
            print("FIRSTORDERNUMBER : $firstOrderNumber");
            setState(() {
              loading = false;
            });
          }
        });
        print("Settting value of existing order now...");
        existingOrder = true;
        print("Existing order is now $existingOrder");
      }
      // print("Existing order is now $existingOrder");
      else {
        print("\n\nEntering existing order....\n");
        orderRepo
            .addAdditionalOrder(
                _productOrder, _cart, _order, firstOrderNumber, this.payment)
            .then((value) {
          if (value is Order) {
            setState(() {
              loading = false;
            });
          }
        });
      }
    });
  }

从控制台输出：

I/flutter ( 6925): VALUE of x inside addOrder = 1
I/flutter ( 6925): Current value of EXISTING : false
I/flutter ( 6925): Entering not existing order....
I/flutter ( 6925): VALUE of x inside addOrder = 2    ---> See the problem. It came back to increment X before the await is complete.  
I/flutter ( 6925): Current value of EXISTING : false
I/flutter ( 6925): Entering not existing order....

//现在，它给出了AWAIT的结果，它应该在...之前等待....

I/flutter ( 6925): The response of first order is : <JSON RESPONSE from first addOrder execution...coming late..>
I/flutter ( 6925): The value is now Instance of 'Order'
I/flutter ( 6925): FIRSTORDERNUMBER : 141
I/flutter ( 6925): Settting value of existing order now...
I/flutter ( 6925): Existing order is now true
I/flutter ( 6925): The response of first order is :

有什么提示吗？我怎么不执行await orderRepo.addOrder(_order, this.payment).then((value) {之前完成的所有其他动作？连续好几天都在进行试用n错误

Answer 1

我认为它应该对您有用！

myFunc() async {
  for(File file in files) {
    await saveFiles(file);
  }
}

Answer 2

像这样尝试 map（）


await Future.wait(carts.map((_cart)async{

  //your code here


}));

Answer 3

使用then函数的状态只是使用await。

if (!existingOrder) {
    print("\n\nEntering not existing order....\n");
    var value = await orderRepo.addOrder(_order, this.payment);
    if (value is Order) {
        print("The value is now $value");
        firstOrderNumber = value.id.toString();
        print("FIRSTORDERNUMBER : $firstOrderNumber");
        setState(() {
          loading = false;
        });
      }
    print("Settting value of existing order now...");
    existingOrder = true;
    print("Existing order is now $existingOrder");
  }

Answer 4

此线程的解决方案在My async call is returning before list is populated in forEach loop中，很少有人在评论中建议。由于他们发表了评论，因此无法将其标记为答案。。因此，为了将来某人的利益共享链接！

Flutter异步/等待在forEach内部不起作用

4 个答案: