Apache – How to populate required parameters in a custom MXML tag

apache-flexcomponents

Here's the Class:

package fnc {
    import mx.containers.Canvas;

    public class Deck extends Canvas {

        protected var _chipCount:int;

        public function Deck(chipCount:int) {
            /* Associate some chips with this deck */
            _chipCount = chipCount;
        }

        public function get chipCount():int {
            return _chipCount;
        }
    }
}

Here's the MXML:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" xmlns:ns1="fnc.*">
    <ns1:Deck horizontalCenter="0" verticalCenter="0">
    </ns1:Deck>
</mx:Application>

Running this application gets this error:

ArgumentError: Error #1063: Argument count mismatch on fnc::Deck(). Expected 1, got 0.
at mx.core::Container/createComponentFromDescriptor()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\Container.as:3579]
at mx.core::Container/createComponentsFromDescriptors()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\Container.as:3493]
at mx.core::Container/createChildren()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\Container.as:2589]
at mx.core::UIComponent/initialize()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\UIComponent.as:5370]
at mx.core::Container/initialize()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\Container.as:2526]
at mx.core::Application/initialize()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\core\Application.as:846]
at Practice/initialize()[C:\Documents and Settings\LocalService\My Documents\Flex Builder 3\Practice\src\Practice.mxml:0]
at mx.managers::SystemManager/http://www.adobe.com/2006/flex/mx/internal::childAdded()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\managers\SystemManager.as:2009]
at mx.managers::SystemManager/initializeTopLevelWindow()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\managers\SystemManager.as:3234]
at mx.managers::SystemManager/http://www.adobe.com/2006/flex/mx/internal::docFrameHandler()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\managers\SystemManager.as:3064]
at mx.managers::SystemManager/docFrameListener()[C:\autobuild\3.2.0\frameworks\projects\framework\src\mx\managers\SystemManager.as:2916]

Adding chipCount="0" to the MXML like this:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" xmlns:ns1="fnc.*">
    <ns1:Deck chipCount="0" horizontalCenter="0" verticalCenter="0">
    </ns1:Deck>
</mx:Application>

Gets this compile error:

Severity and Description Path Resource Location Creation Time Id
Property 'chipCount' is read-only. Practice/src Practice.mxml line 3 1242656555328 26

How do I specify the initial chip count?

Best Answer

In answer to brd6644 comment :

package
{
    import mx.containers.Canvas;

    public class Deck extends Canvas
    {
        protected var _chipCount:int;
        private var chipCountChanged:Boolean;

        public function Deck()
        {
            super();
        }

        public function set chipCount(value:int):void
        {
            if (chipCount != value)
            {
                _chipCount = value;
                chipCountChanged = true;
                invalidateProperties();
                //call invalidateSize() if changing chipCount value may change the size of your component
                //call invalidateDisplayList() if changing chipCount value need a redraw of your component
            }
        }

        public function get chipCount():int
        {
            return _chipCount;
        }

        override protected function commitProperties():void
        {
            super.commitProperties();

            if (chipCountChanged)
            {
                chipCountChanged = false;
                //here update properties that change because of chipCount new value.
            }
        }

    }
}
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