On 1/26/2010 8:31 PM, Wally Kolcz wrote:
I am perplexed. I have a Singleton called ShoppingCart. In it there is
a single public variable called cart which is an ArrayCollection. I am
trying to use it as the shopping cart.
Here is my Singleton:
/package com.earth.model
{
import mx.collections.ArrayCollection;
[Bindable]
public final class ShoppingCart {
private static var instance:ShoppingCart;
public var cart:ArrayCollection;
public function ShoppingCart(singletonEnforcer:MySingletonEnforcer) {
if (singletonEnforcer == null) {
throw new Error ("ShoppingCart is a singleton class, use
getInstance() instead");
}
}
public static function getInstance():ShoppingCart {
if (instance == null)
instance = new ShoppingCart(new MySingletonEnforcer());
return instance;
}
}
}
class MySingletonEnforcer {}/
I am trying to create a function to check to see if the cart has a
product in it by productID. If not, then add a product Object. If it
is there, update the record with the new quantity.
Here is the function.
/import com.earth.model.ShoppingCart;
public var cursor:IViewCursor;
public function addToCart(product:Object, qty:Number):void {
var cursor =
ShoppingCart.getInstance().cart.createCursor();
if (cursor.findAny(product.productID)){
cursor.current.qty += qty;
}else{
var prod:Object = new Object;
prod.productName = product.productName;
prod.qty = qty;
prod.productID = product.productID;
ShoppingCart.getInstance().cart.addItem(prod);
}
updateTotal();
}/
When I try to invoke the function, it throws an error: *TypeError:
Error #1009: Cannot access a property or method of a null object
reference.*
Nevermind, figured it out. :-)
I have used this Singleton before and it worked fine storing a user's
information. Please help.
