topic Re: Live Layer Widget - only return records in extent in ArcGIS API for Flex Questions

Live Layer Widget - only return records in extent

SusanMordy1 — Thu, 10 Jun 2010 20:02:51 GMT

I am wanting to modify the Live Layer Widget so only features (points) in the current map extent are queried and have the results shown on the map. Has anyone done this or does anyone know how to accomplish this?

Thanks!

Susan

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Thu, 10 Jun 2010 20:49:53 GMT

Susan,

In theory (not tested) it should be as simple as adding

query.geometry = map.extent;

to the queryFeatures function in the LiveLayerWidget.mxml

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Thu, 10 Jun 2010 21:09:23 GMT

Robert,

Thanks for your suggestion! I tried it, but the live layer widget still returns all records (not just the records for the map extent).

Any other ideas?

private function queryFeatures():void
   {
    if (queryLayer)
    {
     var queryTask:QueryTask = new QueryTask(queryLayer);
     queryTask.disableClientCaching = true;
     var query:Query = new Query();
     query.outFields = queryFields.split(",");
     query.returnGeometry = true;
     query.where = queryExpr;
     query.outSpatialReference = map.spatialReference;
     queryTask.execute(query, new AsyncResponder(onResult, onFault));
     showMessage(loadingLabel, true);
     query.geometry = map.extent;

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Sat, 11 Dec 2021 18:39:21 GMT

Susan,

You did not put the line in the right spot.

private function queryFeatures():void
{
if (queryLayer)
{
var queryTask:QueryTask = new QueryTask(queryLayer);
queryTask.disableClientCaching = true;
var query:Query = new Query();
query.outFields = queryFields.split(",");
query.returnGeometry = true;
query.where = queryExpr;
query.outSpatialReference = map.spatialReference;
query.geometry = map.extent;
queryTask.execute(query, new AsyncResponder(onResult, onFault));
showMessage(loadingLabel, true);

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Thu, 10 Jun 2010 21:43:35 GMT

Thanks Robert! My mistake 😮

It does work now - thanks - but only in part.

The initial display is correct (eg: zoom to particular area and only those records are displayed - this is great). However, when I pan the map or zoom to another area, the live layer widget is not updated - it still displays the original records.

Any ideas?

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Fri, 11 Jun 2010 00:37:49 GMT

Susan,

Yep, you would have to listen for the map zoomEnd and PanEnd (as Map Extent Change get fired way to often) and have that listener call the queryFeatures function.

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Fri, 11 Jun 2010 16:35:31 GMT

Thanks Robert. Do you know how I can do this?

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Sat, 11 Dec 2021 18:39:24 GMT

Susan,

Add these to the init function.

                      map.addEventListener(PanEvent.PAN_END, fireQuery);
    map.addEventListener(ZoomEvent.ZOOM_END,fireQuery);

Then add this new function

private function fireQuery(Evt:Event):void
   {
    queryFeatures();
   }

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Sat, 11 Dec 2021 18:39:26 GMT

Hi Robert,

I added the below code to livelayerwidget.mxml but then my swf file doesn't build. I am likely putting the code in the wrong place. I placed the function fireQuery last.

private function init():void
   {
    graphicPointSym = new PictureMarkerSymbol(widgetIcon, 25, 25);
    graphicsLayer = new GraphicsLayer();
    graphicsLayer.symbol = graphicPointSym;
    map.addLayer(graphicsLayer);
    map.addEventListener(PanEvent.PAN_END, fireQuery);
    map.addEventListener(ZoomEvent.ZOOM_END,fireQuery);
    if (configXML)
    {

Would you be able to provide some direction as to where I should place your code?

Thanks for your help,

Susan

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Mon, 14 Jun 2010 18:55:36 GMT

Susan,

Here is a zip that has the complete LiveLayerWidget.mxml. It has been tried and tested.

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Mon, 14 Jun 2010 19:10:46 GMT

Hi Robert,

Thanks so much!

I get the attached message when I try to open your zip file.

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Mon, 14 Jun 2010 19:37:02 GMT

Susan,

Here is the mxml just renamed to dot txt. so when you download it just change the extension to dot mxml and overwrite your current LiveLayerWidget.mxml in your src.

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Mon, 14 Jun 2010 20:27:10 GMT

Hi Robert

I think the mxml file did not get attached.

Susan

Re: Live Layer Widget - only return records in extent

RobertScheitlin__GISP — Mon, 14 Jun 2010 20:39:37 GMT

Susan,

Lets try that again. I had to rename the file ext to lpk to get past the file size limit of a txt file. Still the same thing just rename to mxml when you get it.

Re: Live Layer Widget - only return records in extent

SusanMordy1 — Mon, 14 Jun 2010 21:25:19 GMT

Thanks so much Robert!!

This is a big help to me.

I guess this forum does not yet allow users to 'star' that a thread has been answered?

Thanks again,

Susan