How to Create a Visualforce page that opens a custom lookup page in Salesforce?

Hi,

Try this code -

Apex Class :-

public with sharing class CustomLookupManager {
public String selectedPhoneNumber {get;set;}
public String selectedPhoneNumberContactName {get;set;}
public String selectedObject {get;set;}
public String selectedField {get;set;}
public list<PhoneNumberDetail> getPhoneLocationsForGivenNumber1 {get;set;}

private Map<String, Schema.SObjectType> schemaMap{
get{
if(schemaMap == null){
schemaMap = Schema.getGlobalDescribe();
}
return schemaMap;
}private set{}
}

public list<selectOption> allFieldsForSelectedObject {get;set;}
/*Controller*/
public CustomLookupManager(){
allFieldsForSelectedObject = new list<selectOption>();
}

/*To get all object which have phone numbers*/
public list<selectOption> getsObjects(){
selectedPhoneNumber = ''; //to reset phone numbers field
list<selectOption> objectsList = new list<selectOption>();
list<String> tempObject = new list<String>{'Account','Lead',
'Opportunity','Contact','Case'};
objectsList.add(new SelectOption('','--Select Object--'));
Map<String, Schema.SObjectType> gd = schemaMap;
Schema.DescribeSObjectResult r;
Schema.SobjectType sobjecttype;
for(String objectKey: gd.keySet()){
sobjecttype = gd.get(objectKey);
r = sobjecttype.getDescribe();
if((r.getName()).contains('__c'))
objectsList.add(new SelectOption(r.getName(), r.getLabel()));
}
for(string obj:tempObject){
objectsList.add(new selectOption(obj,obj));
}
return objectsList;
}

/*To get all fields on the basis of object*/
public list<selectOption> getFieldsForSelectedObject(){
selectedPhoneNumber = ''; //to reset hone number field
list<selectOption> fieldsName = new list<selectOption>();
try{
if(selectedObject != null || selectedObject != ''
|| selectedObject != '--Select Object--'){
Map<String, Schema.SObjectField> fieldMap = schemaMap.get(selectedObject).
getDescribe().fields.getMap();
for(Schema.SObjectField sfield : fieldMap.Values()){
schema.describefieldresult dfield = sfield.getDescribe();
schema.Displaytype disfield= dfield.getType();
system.debug('#######' + dfield );
if(dfield.getType() == Schema.displayType.Phone){
fieldsName.add(new SelectOption(dfield.getName(),dfield.getLabel ()));
}
}
}
}catch(Exception ex){
apexPages.addMessage(new ApexPages.message(ApexPages.severity.ERROR,
'There is no Phone or Fax Field Exist for selected Object!'));
}
return fieldsName;
}
/*to populate field*/
public void populateFields(){
allFieldsForSelectedObject = getFieldsForSelectedObject();
}

/*Phone Number's Records*/
public class PhoneNumberDetail{
public String contactName{get;set;}
public PhoneNumberDetail(String contactName){
this.contactName = contactName;
}
}
}

Visualforce page code:-

<table class="list" border="0" cellspacing="0" cellpadding="0"
style="width:44% !important">
<tr class="headerRow">
<th><b>Select Object</b></th>
<th><b>Select Field</b></th>
<th><b>Value</b></th>
</tr>
<tr>
<td style="white-space:nowrap;">
<apex:selectList size="1" value="{!selectedObject}" id="selectedObjectId">
<apex:selectOptions value="{!sObjects}" />
<apex:actionSupport event="onchange" action="{!populateFields}"
rerender="selectfield,SearchPanelId" status="ajaxStatus"/>
</apex:selectList>
<apex:actionStatus id="ajaxStatus">
<apex:facet name="start">
&nbsp;
<apex:image value="{!$Resource.ajaxLoad}" height="16"
width="16" />
</apex:facet>
</apex:actionStatus>
</td>
<td>
<apex:selectList size="1" value="{!selectedField}" id="selectfield" >
<apex:selectOption itemValue="" itemLabel="--Select--"/>
<apex:selectOptions value="{!allFieldsForSelectedObject}"/>
</apex:selectList>
</td>
<td style="white-space:nowrap;">
<apex:inputText id="phoneNumberFieldId" value="{!selectedPhoneNumber}"/>
<apex:inputHidden id="phoneNameFieldId"
value="{!selectedPhoneNumberContactName}"/>
<a href="#" id="acc3_lkwgt" onclick="openLookupPopup();" tabindex="2"
title="Parent Account Lookup (New Window)" style="text-decoration: none;">
<img src="/s.gif" alt="Parent Account Lookup (New Window)"
class="lookupIcon"
onblur="this.className = 'lookupIcon';"
onfocus="this.className = 'lookupIconOn';"
onmouseout="this.className = 'lookupIcon';this.className = 'lookupIcon';"
onmouseover="this.className = 'lookupIconOn';this.className = 'lookupIconOn';"
title="Parent Account Lookup (New Window)"/>
</a>
<span class="helpButton" id="Phone.Search-_help">
<label for="phoneNumberFieldId"></label>
<img src="/s.gif" alt="" class="helpOrb" title=""/>
<script type="text/javascript">
sfdcPage.setHelp('Phone.Search', '<table><tr><td><center></center>
</td></tr><tr><td>Custom lookup Example</td></tr></table>');
</script>
</span>
</td>
</tr>
</table>

Hope this helps.