LinkElement become NOT clickable when it scroll out of TextArea view

Question

Hi:
I am writing a online call center product with flash builder 4.5.
I found a tricky problem with LinkElement.
I use the TextArea as the display stage for each incoming and outgoing message. Obviously, the messages includes image and href.
I use LinkElement to display them.
As conversation continues, the TextArea's view scrolls to display more and more content.
When LinkElement scrolls out of the viewable area of TextArea, it becomes NOT clickable!!!
If I change the size or height of TextArea, make the LinkElement shows in view of TextArea, it becomes Clickable.
But changing the size of TextArea is not a workable way to fix this problem, espetially for a long conversation.
The source code is too long, I have to show some snapshot.
=============================================================================
Following is function to generate Paragraph to be inserted into TextArea.
private function imageToLocalParagraph(
role:int, customerId:int, stationId:int, imageTitle:String, imageUrl:String):ArrayList{
var selfName:String = getRoleName(role, customerId, stationId);
var color:uint = getColor(role);
var timeStr:String = getTimeString();
var list:ArrayList = new ArrayList();
var p:ParagraphElement = new ParagraphElement();
var span:SpanElement = new SpanElement();
span.text =
timeStr + " " + selfName;
span.fontSize = _fontSize;
span.color = color;
p.addChild(span);
list.addItem(p);
var p2:ParagraphElement = new ParagraphElement();
var inf:Object = {color:0xFF0000};  
p2.linkHoverFormat = inf;
var link:LinkElement = new LinkElement();
link.href = imageUrl;
link.target = "_blank";
link.addEventListener(FlowElementMouseEvent.CLICK, onImageClick);
var linkSpan:SpanElement = new SpanElement();
linkSpan.text = "点击打开" + imageTitle;
linkSpan.fontSize = _fontSize;
linkSpan.color = color;
link.addChild(linkSpan);
p2.addChild(link);
list.addItem(p2);
return list;
Following is the TextArea that contains each paragraph.
=================================================================
<s:TextArea id="textArea"
editable="false"
focusEnabled="true"
horizontalCenter="0"
width="100%"
height="70%">
<s:textFlow>
<s:TextFlow>
<s:p><s:a href="http://adobe.com/" target="_blank"></s:a></s:p>
</s:TextFlow>
</s:textFlow>
</s:TextArea>
When sprite is created complete, event listener is set for TextArea and this. ParagraphElementEvent is new defined event to receive paragraph list.
this.textArea.textFlow.addEventListener(
CompositionCompleteEvent.COMPOSITION_COMPLETE, compositionCompleteHandler);
this.addEventListener(ParagraphElementEvent.TYPE, onParagraphElementEvent);
When receiving paragraph list event, TextArea will add it and auto scroll view to bottom.
========================================================================================== ============
private function onParagraphElementEvent(event:ParagraphElementEvent):void {
if (event.eventId == this._customer.customerId) {
var list:ArrayList = event.paragraphElementList;
for (var i:int = 0; i < list.length; i++) {
var p:ParagraphElement = (ParagraphElement)(list.getItemAt(i));
this.textArea.textFlow.addChild(p);
// auto scrolling to bottom with 3 ways, the last one is perfect
// (1) this.textArea.appendText("");
// (2) this.textArea.scrollToRange(int.MAX_VALUE, int.MAX_VALUE);
// (3) call scrollToBottom twice when textFlow.addChild and textFlow.CompositionCompleteEvent
scrollToBottom();
private function compositionCompleteHandler(event:CompositionCompleteEvent):void {
scrollToBottom();
private function scrollToBottom():void {
this.textArea.validateNow();
var maximum:Number = this.textArea.scroller.verticalScrollBar.maximum;
this.textArea.scroller.verticalScrollBar.value = maximum;
I don't think it is a problem of Flash builder 4.5.
LinkElement is a commen component.
Thanks
Steven

Answer 1

hi:
the reason has been figured out:
It results from CompositionCompleteEvent.COMPOSITION_COMPLETE.
this.textArea.textFlow.addEventListener(CompositionCompleteEvent.COMPOSITION_COMPLETE, compositionCompleteHandler);
If we scrolls the text area to show the LinkElement invisible,
Click the the Link element, will trigger CompositionCompleteEvent again.
In my implementation, CompositionCompleteEvent  will scrolls the text area to bottom immediately.
It looks that the link not works.
The reason is found, but another question is created:
What is the solution for the text area, which satisfys two aspects:
(1) auto scroll to bottom;
(2) make the link element workable when scrolls.
This is important for IM applications.