Flex 4 Examples

QTP runtime error. TypeError: Error #1006: showConnectionAttemptMessage is not a function.

roustalski — Thu, 26 Jan 2012 18:45:19 +0000

If you compile an air application against the latest Flex 4.6 SDK and include the QTP and automation libraries, you will hit a wall:

TypeError: Error #1006: showConnectionAttemptMessage is not a function.

at mx.automation.qtp::ClientSocketHandler()[C:\work\flex\dmv_automation\projects\qtp_air\src\mx\automation\qtp\ClientSocketHandler.as:163]
at mx.automation.qtp::QTPAgent/applicationCompleteHandler()[C:\work\flex\dmv_automation\projects\qtp_air\src\mx\automation\qtp\QTPAgent.as:127]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.managers::SystemManager/preloader_preloaderDoneHandler()[E:\dev\4.y\frameworks\projects\framework\src\mx\managers\SystemManager.as:2677]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.preloaders::Preloader/displayClassCompleteHandler()[E:\dev\4.y\frameworks\projects\framework\src\mx\preloaders\Preloader.as:582]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at spark.preloaders::SplashScreen/dispatchComplete()[E:\dev\4.y\frameworks\projects\mobilecomponents\src\spark\preloaders\SplashScreen.as:545]
at spark.preloaders::SplashScreen/preloader_initCompleteHandler()[E:\dev\4.y\frameworks\projects\mobilecomponents\src\spark\preloaders\SplashScreen.as:514]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.preloaders::Preloader/dispatchAppEndEvent()[E:\dev\4.y\frameworks\projects\framework\src\mx\preloaders\Preloader.as:380]
at mx.preloaders::Preloader/appCreationCompleteHandler()[E:\dev\4.y\frameworks\projects\framework\src\mx\preloaders\Preloader.as:590]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.core::UIComponent/dispatchEvent()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:13152]
at mx.core::UIComponent/set initialized()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:1818]
at mx.managers::LayoutManager/validateClient()[E:\dev\4.y\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1090]
at mx.core::UIComponent/validateNow()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:8077]
at spark.components::WindowedApplication/window_resizeHandler()[E:\dev\4.y\frameworks\projects\airspark\src\spark\components\WindowedApplication.as:2671]

Please vote for the bug to be addressed if you use automation. Is anyone else seeing this error?

As a workaround, we are using a pre-release version of the SDK (build 23043).

DropDownController PopupAnchor

roustalski — Tue, 08 Nov 2011 21:04:29 +0000

Lets pretend you have a popup that you want to show when a button is clicked, as in the following example:

How do you easily manage when the popup is closed in this case?

Rather than having to manage opening and closing the popup when the button is clicked and the user interacts with the application elsewhere, simply use a DropDownController.

Garbage Collection Strategy Reiterated

roustalski — Mon, 07 Nov 2011 14:52:36 +0000

A new article was recently published on adobe’s devnet providing another recap of how memory is managed by Flash. I wanted to reiterate the importance of diligently clearing the stack memory of references to the heap memory in order to minimize the work of the collector in the Mark and Sweep phase.

You, as the developer, can optimize your code by helping the Mark and Sweep phases of garbage collection occur less often. By keeping your stack references cleared of objects on the heap, the zero count table algorithm can clean up the memory before mark and sweep has to occur.

Getter & Setter accessors with different namespaces

roustalski — Fri, 21 Oct 2011 13:31:24 +0000

Although the bug is still open, you are able to create a getter/setter combo for a property with different namespaces. Sweet!

You will get a compile error when trying to write to the read only property, and you will get a runtime error if you try bracket notation on the object to set the property.

ButtonBar radio logic hack

roustalski — Fri, 30 Sep 2011 20:04:49 +0000

Update: Set the requireSelection property to true.

When the button bar is used as a navigation tool for a set of tabs, it doesn’t make sense for the selected button to be unselected if the user clicks on it.

It is also fairly typical for a result handler of the IndexChangeEvent.CHANGED to utilize the button bar’s selectedItem property to access a piece of data. This causes runtime errors when the selected item is no longer selected because of a re-click on the selected button.

Lets Look at a simple example:

Lets say you have that type of situation all over your code and you are afraid some handlers might slip through the cracks, so you decide to override the ButtonBar to prevent the change event from occuring when the selected button is clicked. Something like this.

All is well, right? Nope! Visually the button is no longer selected. Sadly, the only fix that I could come up with after trying loads of things including listening and hijacking other events and overriding protected and mx_internal events was the following.

Workspace in use or Cannot be Created

roustalski — Fri, 23 Sep 2011 13:22:09 +0000

If you close FlashBuilder and it doesn’t shut down correctly, sometimes a .lock file will be left in the .metadata directory of your workspace.

If you try and restart FB with the .lock file present, you will get an error message about the workspace being in use. Either make sure the java program is killed or remove the lock file manually in order to reload FB.

This seems to happen to me every time I shut down with the latest version ]:

mx Vertical Scroll Position

roustalski — Tue, 14 Jun 2011 12:39:44 +0000

In regards to my post about maintaining vertical scroll position, James asked how the same would be done for mx based components. Here is an example using an mx:DataGrid.

Here is an example of the problem:

This is one way to solve the lost scroll position.

Flex 4 height limit of 10,000?

roustalski — Wed, 08 Jun 2011 13:30:43 +0000

In my post about vertical scroll speed I show a code example of a scroller with several nested groups. A typical design of websites these days is to have a content area in the middle with an ever-expanding height and some sort of repeating background or colors on the sides – Just look at the layout of the majority of blogs, including my own.

Writing a flex app with the same design where you can scroll a lot of content vertically with a solid background color is a pretty typical use-case, but you will quickly find a limitation with using the primitive class Rect as a background: maxHeight = 10,000.

I’ve slightly modified my example from the vertical scroll speed post to demonstrate the layout I’m talking about:

Run that application with more labels until the Rect is truncated. In case you were wondering, UIComponent sets maxHeight for you to 10,000 by default.

An easy fix is highlighted below:

Simple TLF Text Editor

roustalski — Fri, 27 May 2011 18:58:07 +0000

I found a great TLF editor that is simple and to the point, it is under the MIT license, and is of course open source.

I don’t remember the combination of search terms to find it, but I’ve looked for something like this before and was unable to find it despite it being written in Q3 last year. The other examples that I’ve seen are way too heavy or are just plain bad.

Flex 4 Vertical Scroll Speed

roustalski — Wed, 18 May 2011 18:40:36 +0000

By default, scrolling content when using the Scroller component occurs very slowly – Even down to 1px per event.

Try running the following example:

In order to bring scrollable content using a Scroller up to normal web standards (say 50px or 100px per event) with a setup like the above, you have to override the VScrollbar and assign a custom skin to the scroller that uses the override.

The overridden vertical scrollbar:

package
{
    import flash.events.MouseEvent;
    
    import mx.core.mx_internal;
    
    import spark.components.VScrollBar;
    import spark.core.IViewport;
    
    use namespace mx_internal;
    
	[Style(name="movementDelta", inherit="yes", type="number", format="length")]
    public class VScrollBar extends spark.components.VScrollBar
    {
		public function VScrollBar()
		{
			setStyle("movementDelta", 50);
		}
		
        override mx_internal function mouseWheelHandler(event:MouseEvent):void
        {
			var viewport:IViewport = this.viewport;
            if ( viewport == null || !viewport.visible || event.isDefaultPrevented() )
                return;
            
			var delta:Number = event.delta;
			var direction:int = (event.delta > 0) ? -1 : (event.delta < 0) ? 1 : 0;
            var movement:Number = getStyle("movementDelta");
			viewport.verticalScrollPosition += movement * direction;
            event.preventDefault();
        }

    }
}

The Skin Class:

And the modified application using the skinclass. Notice the scrolling speeds with and without the skin that uses the override.