Hi,

Iam trying add the values from the inputfield of the sandard object product to add cart list (whenc addcart command button is clicked i need to to list out the values of product).I am getting error message.

<apex:page standardController="product2" showheader="false" sidebar="false" recordSetVar="Product2" extensions="addcart">
<apex:form >
<apex:pageBlock >
<apex:pageBlockTable value="{!product2}" var="pitem">
<apex:column headerValue="Product">
<apex:outputText value="{!pitem.name}"/>
</apex:column>
<apex:column headerValue="Price">
<apex:outputText value="{!pitem.Product_price__c}"/>
</apex:column>
<apex:column headerValue="Number of products">
<apex:inputText value="{!pitem.Number_of_products__c}"/>
</apex:column>
</apex:pageBlockTable>
</apex:pageBlock>
<apex:commandButton action="{!additems}" value="Add items"/>
<apex:pageBlock title="Your items" id="shopping_cart">
<apex:outputText value="{!message}" />
</apex:pageBlock>
</apex:form>
</apex:page>









Public class addcart {

    public addcart(ApexPages.StandardSetController controller) {
    }
    

public String message { get; set; }
    
public PageReference additems() {
message = 'You bought: ';
for (Displayproducts p: products) {
if (p.count> 0) {
message += p.newproduct.name ; 
System.debug('test'+message);
}
}
return null;
}
 
   
   
      Displayproducts[] products;

public class Displayproducts {
public product2 newproduct { get; set; }
public Decimal count{ get; set; }

public Displayproducts(product2 item) {
this.newproduct = item;
 }
}

    

public Displayproducts[] getproducts() {
if(products == null) {


          Products=new Displayproducts[]{};

      for(Product2 item : [SELECT Id, Name,Number_of_products__c FROM product2]) {
      products.add(new displayproducts(item));
      
                        }

                     }
        return products;
       }
    
  }

System.NullPointerException: Attempt to de-reference a null object
Error is in expression '{!additems}' in component <apex:commandButton> in page addcart: Class.addcart.additems: line 11, column 1
Class.addcart.additems: line 11, column 1