hmmmm it seems the listsrv ate my file. :-(
here, I'll paste it in. And BTW: it is for spark.
package spark.components
{
import flash.events.Event;
import mx.collections.ArrayCollection;
import mx.collections.IList;
import mx.events.CollectionEvent;
public class EmptyItemComboBox extends ComboBox {
protected var _emptyItem:Object = new Object();
protected var _originalDataProvider:IList = null;
private var _enableEmptyItem:Boolean = true;
private var _emptyItemValue:* = -1;
private var _emptyItemLabel:String = "";
public function EmptyItemComboBox() {
super();
_emptyItem.label = _emptyItemLabel;
_emptyItem.value = _emptyItemValue;
addEmptyItem();
addEventListener(Event.CHANGE, onChange);
}
private function onChange(event:Event):void {
dispatchEvent(new Event("isEmptySelectedChanged"));
}
[Bindable]
public function get emptyItem():Object {
return _emptyItem;
}
public function set emptyItem(value:Object):void {
if (_emptyItem != value) {
clearEmptyItem();
_emptyItem = value;
addEmptyItem();
}
}
[Bindable(event="isEmptySelectedChanged")]
public function get isEmptySelected():Boolean {
return (selectedItem == null || (_emptyItem != null && selectedItem
== _emptyItem));
}
override public function set selectedItem(value:*):void {
if (value == null && emptyItem != null) {
super.selectedItem = emptyItem;
} else if (value != selectedItem) {
super.selectedItem = value;
}
dispatchEvent(new Event("isEmptySelectedChanged"));
}
override public function set dataProvider(value:IList):void {
if (_originalDataProvider != null) {
_originalDataProvider.removeEventListener(
CollectionEvent.COLLECTION_CHANGE,
onOriginalCollectionChange);
}
super.dataProvider = value;
_originalDataProvider = (dataProvider as IList);
if(value) {
_originalDataProvider.addEventListener(
CollectionEvent.COLLECTION_CHANGE,
onOriginalCollectionChange
);
if(_enableEmptyItem) {
addEmptyItem();
}
}
}
private function clearEmptyItem():void {
if (emptyItem != null && dataProvider != null
&& dataProvider is IList) {
var dp:IList = dataProvider as IList;
var idx:int = dp.getItemIndex(_emptyItem);
if (idx >=0) {
dp.removeItemAt(idx);
}
}
dispatchEvent(new Event("isEmptySelectedChanged"));
}
private function addEmptyItem():void {
if(_enableEmptyItem) {
if (emptyItem != null) {
if (dataProvider != null && dataProvider is IList &&
dataProvider.length) {
var dp:IList = dataProvider as IList;
var idx:int = dp.getItemIndex(_emptyItem);
if (idx == -1) {
var newDp:ArrayCollection = new
ArrayCollection(dp.toArray().concat());
newDp.addItemAt(_emptyItem, 0);
super.dataProvider = newDp;
typicalItem = newDp.getItemAt(1);
}
}
}
}
dispatchEvent(new Event("isEmptySelectedChanged"));
}
private function onOriginalCollectionChange(event:CollectionEvent):void
{
if (_emptyItem != null) {
dataProvider = _originalDataProvider;
addEmptyItem();
}
}
override protected function commitProperties():void {
try {
super.commitProperties();
} catch(dirtyFix:Error) {
trace("AIIIIIII KERNEL PANIC!!! FIX ME!!!!!!!!!!!!!!!!!!!");
}
}
public function get enableEmptyItem():Boolean {
return _enableEmptyItem;
}
public function set enableEmptyItem(value:Boolean):void {
_enableEmptyItem = value;
}
public function get emptyItemValue():* {
return _emptyItemValue;
}
public function set emptyItemValue(value:*):void {
_emptyItemValue = value;
_emptyItem.value = value;
}
public function get emptyItemLabel():String {
return _emptyItemLabel;
}
public function set emptyItemLabel(value:String):void {
_emptyItemLabel = value;
_emptyItem.label = value;
clearEmptyItem();
addEmptyItem();
// LogObj(emptyItem);
}
}
}
> Date: Tue, 10 Apr 2012 10:30:53 -0700
> Subject: Re: combo box
> From: s9tpep...@apache.org
> To: flex-dev@incubator.apache.org
>
> On Tue, Apr 10, 2012 at 10:23 AM, David Coleman <
> david_coleman_...@hotmail.com> wrote:
>
> > Hi everyone. Mike's most recent mail (mentioning that ComboBoxes have
> > changed nearly every other release) made remember something that i have had
> > sitting around in my personal files for some time. It is a tweak to the
> > combo box that allows you to have a blank item as the first item, allowing
> > you to de-select the selected item and reset the combo to empty. It has a
> > configurable value (which defaults to -1) and a configurable label to show
> > in the list (in case you want it to say "choose a city" or something else
> > more context appropriate).
> >
> > I'm attaching the file. Maybe it is something worth considering. It is a
> > behavior that is definitely lacking when you compare flex to other form
> > entry UI/UX approaches. The ability to "cancel" your selection in a combo
> > box is rather basic and I've always been mildly surprised that it has never
> > been introduced.
> >
> > Cheers!
> > David
> >
>
> Hi David,
>
> First of all welcome to the group! I don't see your file attachment, but
> just wanted to ask is that for an MX component or Spark? Reason I ask is I
> believe there is a prompt property on the Spark component to set a message,
> or make it blank, when selectedIndex equals -1. Just throwing that out
> there...
>
> --
> Omar Gonzalez
> s9tpep...@apache.org
