Setting default field values in apex for new objects

Question

We need to set some default values in apex on a custom object before it is created. The user should ideally work with the standard object page - we don't want to re-create the whole page in visualforce if not necessary.

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Approach 1

Redirect the 'New' button to a custom VF page which loads the defaults and passes them on to the standard page via redirect using URL parameters.

Page (partial):

<apex:page standardcontroller="MyObj__c"
    extensions="MyObjController"
    action="!redirectDefaults">

Controller (partial):

public PageReference redirectDefaults() {
    string defName = someComplexLogic();
    PageReference retPage = new PageReference('/a0H/e?Name' + defName);
    return retPage.setRedirect(true);
}

Question: The problem here is that fields must be passed in a locale specific format : you have to know the user locale and then pass mm/dd/yyyy or dd.mm.yyyy as the case may be. How can this be done?

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Approach 2

Re-create the page in visual force as an extension of a standard controller. This is more work but I assume there must be a way to initialise an instance of myObj before the page is displayed.

Question: How do I initialise myObj in my controller before the form is loaded?

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Any better approaches than these are more than welcome!

Answer 1

For the Approach2 i would take ApexPages.StandardController:

public with sharing class YourController{

    private MyObj__c obj;

    public YourController(ApexPages.StandardController controller){
        this.obj = (MyObj__c)controller.getRecord();
    }
}

More info about StandardController Class

To Approach1.

UPDATE:

It is not a problem to pass date parameter in a current user locale. For that just use format() method of the Date class:

String s = Date.today().format(); 

and then:

'/a0H/e?DateField=' + s

The s looks for me in europe like 21.02.2013. In US it will be 02/21/2013.

From here

And for the default value of a custom field i would try to use a Default Value Formula

Answer 2

OK, I wanted to share some working code which illustrates Approach 2 and also shows how to intercept the save method:

Page:

    <apex:page standardController="Account" extensions="testAccountController">
      <apex:pagemessages /> 
      <apex:form >
            <apex:pageBlock mode="edit">
                <apex:pageBlockButtons > 
                    <apex:commandButton value="Save" action="{!save}"/>
                </apex:pageBlockButtons>
                <apex:pageBlockSection title="Details" columns="1" >
                    <apex:inputField value="{!account.Name}" style="width:300px;"/>
                </apex:pageBlockSection>
            </apex:pageBlock>
        </apex:form>
    </apex:page>

Controller:

    public class testAccountController {

        Apexpages.StandardController stdController;

        public testAccountController(ApexPages.StandardController stdController) {
            this.stdController = stdController;
            Account acct = (Account)stdController.getRecord();
            if (acct.id == null) {
              // Set defaults for new records here
              // This is for fields that can still be changed in the page
              acct.CurrencyIsoCode = someFunction();
            }
        }

        public pageReference save() {
            // Get the secord being saved
            Account acct = (Account)stdController.getRecord();
            // Validate or make adjustments
            if (acct.id == null) {
              // Set defaults for new records here
              // This is for fields that should not be changed in the page
            }
            try {
              return stdController.save();
            } catch (Exception e) {
              ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.FATAL, e.getMessage()));
            }
            return null;
        }

    }