Text Highlighting issue with TextSnapshot object

Question

Hi,
I am working with a digital book application. I make use of swf loader to load swf pages created from pdf. I use TextSnapsot to draw inline text highlight on the pages. The highlight is thoroughly retained on the respective pages throughout the session and later it can be updated/deleted without any problem. Everything was working great till I made the following changes in the swf loading approach to enable page caching:
I am now loading swf loader object into application memory and while doing jumping from one page to other page I am just copying the content of the next page to the current swf loader which is on the display to the user. There are two sets of swf loaders - one for displaying the page and other to cache the next/previous page(s). On the caching side, I load the swf into application memory and after getting it loaded I pick all the contents of the loaded swf page (the children of it's movie clip) into an array collection. While changing the page I copy the cached content into the swf loader's movie clip which is displaying the page.
Now when I highlight on the page on display and navigate back/forth from the page and comeback again to the page where I did the highlighting: It shows the highlight I did. But as soon as I try to draw another highlight on that page, the previous highlight is instantly disappears from the page.
I suspect that the Textsnapshot object which draws highlight while navigating (to the target display page) is different from the one which redraws/update the highlight on the same page next time. Although the Textsnapshot object id for both the objects is same.
Here are some code snippet:
For copying the content from the swf loader object cached in application memory:
        private function copyPageContent():void
            var contentCollection:ArrayCollection = new ArrayCollection();
            _pageContentVO = new PageContentVO();
            _pageContentVO.contentHeight = MovieClip(_swfPageLoader.content).height;
            _pageContentVO.contentWidth = MovieClip(_swfPageLoader.content).width;
            var count:int = MovieClip(_swfPageLoader.content).numChildren;               
            for(var i:int=0;i<count;i++)
                var dispObject:DisplayObject = MovieClip(_swfPageLoader.content).removeChildAt(0);               
                contentCollection.addItem(dispObject);
            _pageContentVO.pageContentCollection = contentCollection;
            _swfPageLoader = null;
For copying the content to the swf loader which is displaying the page:
        private function copyContent(pageContentVo:PageContentVO):void
            for(var i:int = 0;i<pageContentVo.pageContentCollection.length;i++)
                var dispObject:DisplayObject = pageContentVo.pageContentCollection.getItemAt(i) as DisplayObject;
                MovieClip(this.content).addChild(dispObject);
            this.content.height = this.height;
            this.content.width = this.width;
after this I dispatch swf loader's complete manually and in the handler of that event I take the text snap shot object.(highlightManager.as)
Code I use to draw highlight manually(using mouse drag on the page).
       public function setHighlight():void
            removeAll();
            if(_textSnapShot!=null && _textSnapShot.getText(0,_textSnapShot.charCount)!="")
                if(_isCoveredTextSelectedAtAnyInstance)
                    _textSnapShot.setSelected(_beginIndex,_endIndex+1,false); //this is the global variable to the class
                else
                    _textSnapShot.setSelectColor(0xfff100);
                    _textSnapShot.setSelected(_beginIndex,_endIndex+1,true);
                if(saveHighlight)
                    countHighlightedSegments();
Code I use to redraw previously drawn highlight when I return to the page:
       public function showHighlights(textSnapShot:TextSnapshot,currentPageNum:int):void
            if(currentPageNum >= 0)
                textSnapShot.setSelected(0,textSnapShot.charCount,false);
                var pageVO:PageVO = _model.eBookVO.eBookPagesVO.getItemAt(currentPageNum) as PageVO;
                var objColl:ArrayCollection = new ArrayCollection();
                objColl.source = pageVO.highLightSelection;
                for(var i:int=0;i<objColl.length;i++)
                    var highlightVO:HighlightVO = new HighlightVO();
                    highlightVO.beginIndex = objColl.getItemAt(i).beginIndex;
                    highlightVO.endIndex = objColl.getItemAt(i).endIndex;
                    setHighlightedSegment(textSnapShot,highlightVO.beginIndex,highlightVO.endIndex);
        private function setHighlightedSegment(textSnapShot:TextSnapshot,beginIndex:int,endIndex:int):void
            textSnapShot.setSelectColor(0xfff100);
            textSnapShot.setSelected(beginIndex,endIndex,true);
Looking forward to your support to resolve this issue.
Regards,
JS

Answer 1

Hi, I've resolved this issue.
It was a textSnapShot GC issue.
I just added the textsnapshot object into an array to avoid GC and that resolved my issue.