how to populate custom object value in standard detail page layout

Question

I have two object one standard object Leads and one custom object tractor.and tractor is a lookup field in lead object.i am trying to include three input fields and a button for searching a tractor in lead edit page using a button and vf page. everything is working fine except that,on clicking one particular item in list i need to populate that value in the lookup field on the lead detail page.

i tried some url hacking things like this

<apex:outputLink value="javascript:top.window.opener.lookupPick2('editPage','CF00Nq00000025801_lkid','CF00Nq00000025801','{!a.Id}','{!a.Name}', false)"
    rendered="{!NOT(ISNULL(a.Id))}">
        {!a.Name}
</apex:outputLink>

but its not working for me.can any one suggest me some idea to achieve this requirement.

Answer 1

Since you have visualforce page, so clicking the link of the displayed custom object record, save this in the controller and refresh the page.

It is not encouraged to use URL hacking which is very fragile.

Use apex:commandLink to call the controller function and pass the value from your page.

<apex:commandLink value="{!a.Name}" action="{!processLinkClick}">
    <apex:param name="customLookupFieldName" value="{!a.Id}" assignTo="{!customLookupField}"/>
</apex:commandLink>

Controller

public  class LeadTractorExtension{

    public String customLookupField {get; set;}
    public PageReference processLinkClick() {

        //here save the lead record and return to lead detail page
    }

}