ISBLANK(String) Returning false When String.length() Returns 0

I discovered this with version 21.0 of the Salesforce API: When a String's length is 0, the ISBLANK(String) Visualforce function will actually return false instead of true.

Visualforce Developer's Guide, Version 21.0 describes the ISBLANK function as follows:

Determines if an expression has a value and returns TRUE if it does not. If it contains a value, this function returns FALSE.

A search for ISNULL in the documentation returned no real results, which makes me wonder if ISNULL has been unofficially deprecated in favor of ISBLANK.

So, it appears that the only way to know for sure whether a String input has been blanked out is to use the length method and compare it to 0.

apex:define Tag Precedence in Visualforce Templates

I learned something interesting through trial-and-error yesterday:

If you define a set of templates where each successive template "extends" the previous template, the apex:insert tag in all previous templates are available for definition in the final implementing page.

For example, let's take take the following hierarchy of templates:

1. SiteMasterTemplate
2. SiteDepartmentTemplate--contains an apex:composition with template="SiteMasterTemplate"
3. SiteProductTemplate--contains an apex:composition with template="SiteDepartmentTemplate"

Now, if we create a page called SiteSuperMotor that contains an apex:composition with template="SiteProductTemplate", our page can actually use apex:define that define apex:insert elements in SiteMasterTemplate!

Furthermore, let's say that we have apex:insert elements in both SiteDepartmentTemplate or SiteProductTemplate that share the same name attribute as an apex:insert in SiteMasterTemplate, then the SiteSuperMotor page's apex:define would only define the apex:insert in SiteMasterTemplate!

Visualforce Misinterprets Empty xmlns Attributes

For unknown reasons, Visualforce does not handle an empty xmlns attribute inside a DIV tag. Unexpected behavior will result if a DIV tag is used inside a Visualforce page with xmlns="" specified as an attribute.

If a Visualforce page that contains simple HTML is not rendering like the page from which the HTML was copied, checking for empty xmlns attributes may be the key to fixing the problem.

jQuery in Custom Input Components

I'm trying to write my own custom input component that updates values based on button clicks. The component idea is similar to the enhanced jQuery input components created by Joel Dietz, although far less universal in application. An example of Joel's components can be found below.

"enhancedText.component"
sfdcjqueryenhancements

"EnhancedTextController.cls"
sfdcjqueryenhancements

One trick to making the component inputs work is to factor in the quirky DOM ID's generated by Salesforce. This is addressed in the following blog post from Wes Nolte.

"VisualForce Element Ids in jQuery selectors"
The Silver Lining

To clarify Wes's post, the function is defined as follows:

function esc(myid) {
    return '#' + myid.replace(/(:|\.)/g,'\\\\$1');
}

Also, the esc function cannot be called with a literal! The String must be stored in a var first, and the var should then be passed to the esc function.

Whew! I'm not done with my custom input component yet, but I definitely see bright rays of hope.

How to Write to a Custom Component Attribute

I spent a long time trying to figure out why the following code was not working:

<apex:component id="this" controller="MySiteInputAccountIdCtrl"
selfClosing="true">

<apex:attribute name="value" type="Id"
description="Account Id to pass back to the page."
assignTo="{!accountId}"
required="true"/>

<apex:inputText id="accountIdIText"
value="{!accountId}"/>

</apex:component>

accountId was a simple property with a vanilla pair of getter and setter methods. When the component is rendered as a component like <c:MySiteInputAccountId value="{!contact.AccountId}>, contact.AccountId would not update no matter what I typed into the input field.

Several hours later, I took a look back at a custom component that worked (and was also created by me after a similar bout of confusion)... And it turns out that I was writing the input to the wrong object. The correct component markup is as follows:

<apex:component id="this" controller="MySiteInputAccountIdCtrl"
selfClosing="true">

<apex:attribute name="value" type="Id"
description="Account Id to pass back to the page."
assignTo="{!accountId}"
required="true"/>

<apex:inputText id="accountIdIText"
value="{!value}"/>

</apex:component>

I can't believe I forgot this resolution to a 3-hour frustration almost immediately... just to experience a new 6-hour frustration on the same topic. Hopefully writing this down will help me remember my lesson and avoid a third incident.

Conversion Error setting value 'value1 value2 value3' for '#{myMultiselectPicklistValue}'.

Salesforce is great. Apex is great. Visualforce is great.

Until you run into bizarre errors with no obvious explanation, such as the following error:

Conversion Error setting value 'value1 value2 value3' for '#{myMultiselectPicklistValue}'.

This error comes from trying to save the selections from an apex:selectCheckboxes component into a multi-select picklist field. You would think that it's as easy as simply specifying {!property} for the value attribute of the apex:selectCheckboxes component. But, no, it's not.

Multi-select picklist values are stored as String values, with each option delimited with a semicolon.  This is great to know, but what happens with apex:selectCheckboxes? apex:selectCheckboxes expects a List<String>! This discussion board post hints at the annoyance awaiting developers: "Checkboxes not saving".

Basically, to spell it out for myself and for others, here's what we have to do as developers working around this problem.

What we want to write is:


<apex:selectcheckboxes value="{!mPicklistValue}">

... and in the controller ...


public String mPicklistValue { get; set; }

Instead, what we have to write is:


<apex:selectcheckboxes value="{!mPicklistValues}">

... and in the overblown controller ...

private String mPicklistValue;
public List<String> getMPicklistValues() {
    List<String> values = null;
    // Convert mPicklistValue into List of 
    // String values

    if (mPicklistValue != null)
        values = mPicklistValue.split(';');

    return values;
}   // List<String> getMPicklistValues()
public void setMPicklistValues(
        List<String> values) {

    // Convert values into a semilcolon-delimited
    // String value

    if (values == null) {
        mPicklistValue = null;
    }
    else {
        mPicklistValue = '';
        
        for (String value : values) {
            mPicklistValue += value + ';';
        }
    }
}   // void setMPicklistValues(List<String>)

Note the plural name of the custom getter and setter methods. Cheers, indeed.

Samsung Galaxy Tab Test-drive

I had the opportunity to check out the Samsung Galaxy Tab for a few days, and I was very excited at the chance to use Android on a tablet to personally see how it stacks up against the iPad and iOS 4.

The short review:  Galaxy Tab + Android fall way, way short.  Samsung, did you pull an ostrich and just ignore the fact that the iPad has already captured the imagination and desire of the world over the past year?

Anyway, where was I...

First, the good, since the good is little:

• Widgets.  It's nice to see things other than little grids of icons on the home screen.
• Swype input.  Okay, it's pretty cool and revolutionary.  But what the hell is up with the way the rest of the symbol and numeric inputs are displayed?

Grab the popcorn and beer, because the next part may take a while to read.  The bad:

• Unreliable Wi-Fi connection that works about 1 % of the time.  Really, Samsung?  Really?
• Landscape form entry was designed by a masochist.  Who had the bright idea that when we use landscape orientation to enter data on forms that we no longer need to see the form?  Or even the label of the field into which we're typing?
• Thick form factor.  Not appealing.
• Typo on the setup screen relating to Wi-Fi.  See if you can find it.
• 802.1x-secured wireless network did not appear on initial setup but did appear later in Settings.
• Browser bug where the client gets squished into about the top 1/5 of the screen, making it impossible to change the address, see anything or open new tabs.  Basically, I had to kill the app and relaunch it to get back up and running.  If it's going to crash, just crash.  Don't make it a pain for me to relaunch the app.
• Do I really need a Gmail account to access the Marketplace?  Is my Google Account attached to my company email address not good enough for Android?
• And so much more that I couldn't remember it all...

Basically, if I had a choice between having a Samsung Galaxy Tab or having nothing at all, guess what I would choose...  Hint:  It's not having the Galaxy Tab.