Where this doesn’t work is if you change a property inside the object.

So if we have something like this

[Bindable]			
private var myObject : ObjectDataVO;
 
<view:SomeComponent
...
data="{ myObject }"
...
/>

When we set myObject to something the view component gets updated (great so far).
Lets say the myObject has a property text and the view component uses this to display some visual label, then somewhere in the app I change that property, myObject.text = “something else”;
The binding will not trigger as I haven’t actually changed the myObject, just a property inside it.

So how do we fire the binding manually? Well there is the BindingManager class (note this is an excluded class so you’ll not see it in the autocomplete ).
So in this example if I changed the myObject.text property then I could call

BindingManager.executeBindings( this, ‘myObject.text’, myObject );

This would fire of the binding as if the actual myObject had changed so anything listening in will now get updated.

DO NOT USE THIS IN YOUR PRODUCTION CODE
(unless you really need to and understand why you shouldn’t)

This will get rid of any security issues you may be having while in development.

<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM
 "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<site-control permitted-cross-domain-policies="all"/>
<allow-access-from domain="*" secure="false"/>
<allow-http-request-headers-from domain="*"
 headers="*" secure="false"/>
</cross-domain-policy>

Well the IconItemRenderer and LabelItemRenderer have a similar issue. So lets just say you create a list and you wish to skin the list exactly how you like or use it in a tile layout or something other than vertical then you will find some lines above and below your renderers which look out of place. You can’t get rid of them no matter what property styles you set.

The fix is pretty straight forward but why does there have to be some hardcoded values in something that is meant to be very versatile?

So inside the LabelItemRenderer around lines 881 you will see the following. It uses these values to draw separators whether you like it or not.

// separators are a highlight on the top and shadow on the bottom
topSeparatorColor = 0xFFFFFF;
topSeparatorAlpha = .3;
bottomSeparatorColor = 0x000000;
bottomSeparatorAlpha = .3;

So the quickest way of dealing with this is to override the drawBackground function in your own class which is created in LabelItemRenderer. This doesn’t get called from IconItemRenderer so you can quite simple copy the entire function and just remove the separator chunk and do not call super from your function which overrides the drawBackground.

Better still would be to change the hard coded values to styles from a CSS file.

var topSeparatorColor : uint = getStyle( 'topSeparatorColor' );
var topSeparatorAlpha : Number = getStyle( 'topSeparatorAlpha' );
topSeparatorAlpha = isNaN( topSeparatorAlpha ) ? 1 : topSeparatorAlpha;

If you’re setting a Number just remember to check for NaN’s in case you haven’t set a style, uints default to 0 anyway.

So how do you call a function that may have any number of arguments. Well here is the code and it should speak for itself.

 protected function checkSomethingThenCallOtherFunction(
    method : Function, args : Array = null ) : void
 {
    if( something.length < someMaxLimit )
    {
        method.apply( null, args );
    }
    else
    {
        //do something else
    }
}

So how easy is that? Pass in the function and an array of arguments, that’s all.

So in Flashbuilder, under the project properties and then the Flex compiler properties you’ll see something like this

Example for custom arguments

So if you had the following defined, -define=CONFIG::DEBUG,true -define+=CONFIG::SOMETHING_ELSE,false

Then in code you could do the following.

    CONFIG::DEBUG
    private var test : Boolean;
 
    CONFIG::SOMETHING_ELSE
    private function somethingElse() : void
    {
 
    }

The variable and function code will only be included if the compiler argument is true. So in the above example if you called the function ‘somethingElse()’ then this would generate a build error as somethingElse() doesn’t exist. Change the argument to true and it will build fine.

I was customising a DataGrid with various skin parts the other day (Flex 3) and could I get the borderskin to show, heck no! Its been a while since I had to create a DG from scratch so I’d obviously blacked out any previous pain with using the dammed DG.

Anyway why would the borderskin not show? I tried a simple solid border, nope. I tried a custom png graphic taken from Fireworks for the DG’s border, nope. I tried a programmatic skin border and guess what nope – nothing.  The issue was that I had the background alpha set to 1 (which is pretty normal!) and I had set the alternate row colours.

Setting the background alpha to something less than 1 revealed the border so I ended up fudging it by creating the programmatic skin border by whatever the borderThickness is outside the size of the DG.  
So if the DG was meant to be 400px wide and borderThickness was 2, I made the DG 396px wide and drew the border outside that area.  This is what I’ve expect to happen automatically.

Can’t believe I’ve missed this/forgotten this before. Crappy DG.

Well after the unfortunate news that the company I work for are no longer wishing to partake in the RIA party that’s changing the way we look at and use the web/desktop and hence are making myself redundant. I’m looking at this as a great opportunity to expand my knowledge so that I can work with as many forward thinking companies as possible that deal with Flex/Actionscript/AIR or for that matter any RIA technology.
Also I should now have more time to create and sell my own components, of which I had a cracking idea this morning (more on this later hopefully).

Hect I’ll event look at Silverlight or JavaFX if I get the time or the chance. So anyone out there fancy taking on a new contractor with 4 years+ experience in Flex as well as a bunch of other languages I’ve used along the way before I even heard of Flex.

Feel free to contact me at this address.

I’m going to continue to post hints and tips on anything I do as well as posting any new components so watch this space and feel free to contact me if you need any work done in the UK, remote working is always an option as well.

First of if you haven’t got one already, create a uiltily class so features that you use regulary across projects (you could turn this file into a SWC and reference that in you various projects – now that I think about it I explain this as simple tip #3 )

So inside your utility class place the following code

public static function get randomColour() : uint {
	return Math.random() * uint.MAX_VALUE;
}

Then lets just say you require a random colour for anything just call Utility.randomColour, no brackets, no = signs. Because you’ve set the function as a getter using the function name will be enough. This method also means that you don’t need to remember the max/min values for a colour. The uint min and max values are the same as the the min/max values for colours.

e.g.

<mx:Canvas backgroundColor="{Utility.randomColour}"
   width="600"
   height="600">

Utility is the name of the class that holds my utility functions.

I’m sure most folk will have struggled to think of what project they last used a generic function ABC in as they could do with using it for project XYZ and would rather spend 30 mins searching for said function rather than rewrite it.

Well as explained below is a way to stop this from happening and hopefully save you a heap of time.

• Step 1

  – Create a library project.

• So using flexbuilder, go to File->New->Flex Library Project.
• This will create an empty library project.

• Step 2

  – add in your Utilty class to the library project.

• To do this add/create a Utility actionscript file that contains your static functions. Save, and this should then automaticlaly create a SWC file inside the library bin folder. (If it hasn’t and the file added has no errors then check the project properties to make sure the newly added file is being included – see pic)

• Step 3

  – add the reference of the newly created SWC file to any project you intend to use it in.

• So go to your project you wish to use the SWC with, then select the projects properties and inside ‘Flex build path’ select ‘Add SWC’.
• Browse to the the previous library project and select the SWC from its bin folder.

You are now done, any time you update the code in the library project, those changes will be reflected in any project that references the SWC file automatically.

Below is a simple soloution using actionscript to solve this.

First I should state that you need to use the AdvancedDataGrid even if you only need a normal DataGrid.  This is because the AdvancedDataGrid has a method called drawHighlightIndicator(…), which as you’d expect from the name draws the highlight.  Normally this is a single colour, but with a little overriding you’ll be able to change this.

Below is the main snippet of code from the extended AdvancedDataGrid.

override protected function drawHighlightIndicator(  indicator:Sprite, x:Number, y:Number,
	width:Number, height:Number, color:uint,  itemRenderer:IListItemRenderer):void
{
	//The indicator is the highlight, so grab its graphics and clear them
	var g:Graphics = Sprite(indicator).graphics;
	g.clear();
 
	var xPos : Number = 0;
	var yPos : Number = 0;
	//loop through the number of columns in the datagrid
	for(var i : uint = 0; i < this.columnCount; i++){
		//get a random colour
		g.beginFill(randColour);
		//draw the rectanlge that fills the first column
		g.drawRect(xPos, y, this.columns[i].width, height);
		//update the starting X position so that it starts at the begin of the
		//next column
		xPos = xPos + this.columns[i].width;
	}
	g.endFill();
}

using the above you could create a DataGrid like the below which has some left hand columns in light purple and the rest in white. Then on highlight that same light purple colour is used for the white cells and the existing light purple becomes a slightly darker purple.

Check out this link to see a very simple/colourful demo. As ever right click app for full source code.