handleAddItem: function(component, event, helper) {
        var item = event.getParam("item");
                
        var action = component.get("c.saveItem");
//json stringify is not needed I think.       
action.setParams({
            "item": item
        });
        
        action.setCallback(this, function(response){
            var state = response.getState();
            if (component.isValid() && state === "SUCCESS") {        
                var items = component.get("v.items");
                items.push(item);
                component.set("v.items",items);
            }
        });
        $A.enqueueAction(action);
    }

<aura:component controller="CampingListController">
    
    <aura:handler name="init" action="{!c.doInit}" value="{!this}"/>
    <aura:handler name="addItem" event="c:addItemEvent" action="{!c.handleAddItem}"/>
    
    <div class="slds-page-header" role="banner">

      <div class="slds-grid">

        <div class="slds-col">

          <p class="slds-text-heading--label">Camping Items</p>

          <h1 class="slds-text-heading--medium">My Camping Items</h1>

        </div>

      </div>

    </div>

      
  <div aria-labelledby="newitemform">

      <fieldset class="slds-box slds-theme--default slds-container--small">
    
        <c:campingListForm />
    
      </fieldset>

	</div>
    
    
     <aura:attribute name="items" type="Camping_Item__c[]"/>

    <div class="slds-card slds-p-top--medium">
        <header class="slds-card__header">
            <h3 class="slds-text-heading--small">Camping List Items</h3>
        </header>
        
        <section class="slds-card__body">
            <div id="list" class="row">
                <aura:iteration items="{!v.items}" var="item">
                    <c:campingListItem item="{!item}"/>
                </aura:iteration>
            </div>
        </section>
    </div>

</aura:component>

({
    
    doInit: function(component, event, helper) {
    
        var action = component.get("c.getItems");
    
        action.setCallback(this, function(response) {
            var state = response.getState();
            if (component.isValid() && state === "SUCCESS") {
                component.set("v.items", response.getReturnValue());
            }
            else {
                console.log("Failed with state: " + state);
            }
        });
    
        $A.enqueueAction(action);
    },    
    
    handleAddItem: function(component, event, helper) {
        var item = event.getParam("item");
                
        var action = component.get("c.saveItem");
        action.setParams({
            "item": item
        });
        
        action.setCallback(this, function(response){
            var state = response.getState();
            if (component.isValid() && state === "SUCCESS") {        
                var items = component.get("v.items");
                items.push(item);
                component.set("v.items",items);
            }
        });
        $A.enqueueAction(action);
    }
    
})

({
	createItem : function(component, item) {
        var action = component.get("c.saveItem");
    action.setParams({
        "item": item
    });
    action.setCallback(this, function(response){
        var state = response.getState();
        if (component.isValid() && state === "SUCCESS") {
            var items = component.get("v.items");
            items.push(response.getReturnValue());
            component.set("v.items", items);
            component.set("v.newItem",{ 'sobjectType': 'Camping_Item__c',
                    'Name': '',
                    'Quantity__c': 0,
                    'Price__c': 0,
                    'Packed__c': false });
        }
    });
    $A.enqueueAction(action);
		/*var theItems = component.get("v.items");
 
        // Copy the expense to a new object
        // THIS IS A DISGUSTING, TEMPORARY HACK
        var newItem = JSON.parse(JSON.stringify(item));
 
        theItems.push(newItem); 
        component.set("v.items", theItems);
       console.log('theItems helper==',theItems);*/
    
	},
    
    validateItemForm: function(component) {

    // Simplistic error checking
    var validExpense = true;

    // Name must not be blank
    var fld = component.find("ciName");
    var fldVal = fld.get("v.value");
    if ($A.util.isEmpty(fldVal)){
        validExpense = false;
        fld.set("v.errors", [{message:"Name can't be blank."}]);
    }
    else {
        fld.set("v.errors", null);
    }

    // Amount must be set, must be a positive number
    var quantFld = component.find("ciQuantity");
    var quantFldVal = quantFld.get("v.value");
    if ($A.util.isEmpty(quantFldVal) || isNaN(quantFldVal) || (quantFldVal <= 0.0)){
        validExpense = false;
        quantFld.set("v.errors", [{message:"Enter qunatity."}]);
    }
    else {
        // If the amount looks good, unset any errors...
        quantFld.set("v.errors", null);
    }
        
        // Amount must be set, must be a positive number
    var priceFld = component.find("ciPrice");
    var priceFldVal = priceFld.get("v.value");
    if ($A.util.isEmpty(priceFldVal) || isNaN(priceFldVal) || (priceFldVal <= 0.0)){
        validExpense = false;
        priceFld.set("v.errors", [{message:"Enter price."}]);
    }
    else {
        // If the amount looks good, unset any errors...
        priceFld.set("v.errors", null);
    }
    
    return(validExpense);
}
})

<aura:component >
    
     <aura:attribute name="newItem" type="Camping_Item__c"
     default="{ 'sobjectType': 'Camping_Item__c',
                    'Name': '',
                    'Packed__c': false,
                    'Price__c': '0',
                    'Quantity__c': '0' }"/>
	<aura:registerEvent name="addItem" type="c:addItemEvent"/>
    
  <div aria-labelledby="newitemform">
      <fieldset class="slds-box slds-theme--default slds-container--small">
    
        <legend id="newitemform" class="slds-text-heading--small 
          slds-p-vertical--medium">
          Add Camping Item
        </legend>
    
        <form class="slds-form--stacked">
    
          <div class="slds-form-element slds-is-required">
              <div class="slds-form-element__control">
                  <ui:inputText aura:id="name" label="Camping Item Name"
                      class="slds-input"
                      labelClass="slds-form-element__label"
                      value="{!v.newItem.Name}"
                      required="true"/>
              </div>
         </div>
            
          <div class="slds-form-element">
              <ui:inputCheckbox aura:id="packed" label="Packed?"
                  class="slds-checkbox"
                  labelClass="slds-form-element__label"
                  value="{!v.newItem.Packed__c}"/>
          </div>
            
        <div class="slds-form-element">
              <div class="slds-form-element__control">
                  <ui:inputCurrency aura:id="price" label="Price"
                      class="slds-input"
                      labelClass="slds-form-element__label"
                      value="{!v.newItem.Price__c}" />
    
              </div>
          </div>
    
         <div class="slds-form-element">
              <div class="slds-form-element__control">
                  <ui:inputNumber aura:id="quantity" label="Quantity"
                      class="slds-input"
                      labelClass="slds-form-element__label"
                      value="{!v.newItem.Quantity__c}"/>
    
              </div>
          </div>
    
          <div class="slds-form-element">
              <ui:button label="Create Camping Item"
                  class="slds-button slds-button--brand"
                  press="{!c.submitForm}"/>
          </div>
    
        </form>
    
      </fieldset>
</div>

</aura:component>

({    
    
    submitForm : function(component, event, helper) {
        
        var validCamping = true;

        // Name must not be blank
        var nameField = component.find("name");
        var expname = nameField.get("v.value");
        if ($A.util.isEmpty(expname)){
            validCamping = false;
            nameField.set("v.errors", [{message:"Camping Item name can't be blank."}]);
        }
        else {
            nameField.set("v.errors", null);
        }

        
        var priceField = component.find("price");
        var price = priceField.get("v.value");
        if ($A.util.isEmpty(price) || isNaN(price) || (price <= 0.0)){
            validCamping = false;
            priceField.set("v.errors", [{message:"Camping Item price can't be blank."}]);
        }
        else {
            priceField.set("v.errors", null);
        }
        
        var quantityField = component.find("quantity");
        var quantity = quantityField.get("v.value");
        if ($A.util.isEmpty(quantity) || isNaN(quantity) || (quantity <= 0)){
            validCamping = false;
            quantityField.set("v.errors", [{message:"Camping Item quantity can't be blank."}]);
        }
        else {
            quantityField.set("v.errors", null);
        }

        if(validCamping){
            
            helper.createItem(component);
            
        }
        
    },
})

({

     createItem : function(component) {
        var newItem = component.get("v.newItem");
        var addEvent = component.getEvent("addItem");
        addEvent.setParams({"item" : newItem});
        addEvent.fire();
        component.set("v.newItem",
                     { 'sobjectType': 'Camping_Item__c',
                    'Name': '',
                    'Packed__c': false,
                    'Price__c': 0,
                    'Quantity__c': 0});
    }

})