topic QueryTask: graphics not being drawn? in ArcGIS JavaScript Maps SDK Questions

QueryTask: graphics not being drawn?

RobertMartin2 — Fri, 09 Aug 2013 22:41:20 GMT

Hi all,

I am trying to implement a query task in my JS app per this tutorial:

https://developers.arcgis.com/en/javascript/jshelp/intro_querytask.html

After a little finagling everything seems to be working fine -- the query returns the expected feature and the callback gets called. But nothing is showing up on the map. Are there any caveats I should know about? This is how I initialize the query, etc.:

// Initialize query task queryTask = new QueryTask('http://myurl');  // Initialize query query = new Query(); query.returnGeometry = true; query.outFields = ['PIND'];  // Initialize info template infoTemplate = new InfoTemplate('${PIND}', 'PIND: ${PIND}');  // Initialize symbol symbol = new SimpleFillSymbol(  SimpleFillSymbol.STYLE_SOLID,  new SimpleLineSymbol(   SimpleLineSymbol.STYLE_SOLID,   new Color([255.0, 0.0, 0.0])  ),  new Color([255.0, 0.0, 0.0, 0.25]) );

And this is my drawing function:

function drawFeatureSet(featureSet) {  try {   // Clear graphics   map.graphics.clear();    // Loop through features   for (feature in featureSet.features) {    feature.symbol = symbol;    feature.infoTemplate = infoTemplate;    map.graphics.add(feature);   }  }  catch(e) {   console.log(e.message);  } }

If I try logging the contents of the graphics layer after adding all I see is ["0"]. Strange...

Thanks for your help!

Re: QueryTask: graphics not being drawn?

derekswingley1 — Fri, 09 Aug 2013 23:09:38 GMT

featureSet.features is an array, not an object so doing for ... in isn't applicable. Instead use something like the showResults function from the page you linked to:

function showResults(featureSet) {     //remove all graphics on the maps graphics layer     map.graphics.clear();      //Performance enhancer - assign featureSet array to a single variable.     var resultFeatures = featureSet.features;      //Loop through each feature returned     for (var i=0, il=resultFeatures.length; i<il; i++) {       //Get the current feature from the featureSet.       //Feature is a graphic       var graphic = resultFeatures;       graphic.setSymbol(symbol);        //Set the infoTemplate.       graphic.setInfoTemplate(infoTemplate);        //Add graphic to the map graphics layer.       map.graphics.add(graphic);     }   }

Also note that setSymbol() method is used rather than setting the symbol property directly.

Re: QueryTask: graphics not being drawn?

RobertMartin2 — Sat, 10 Aug 2013 18:18:44 GMT

That must be it! Thanks Derek. I was thinking the for...in would work along the lines of the Python equivalent. I'll try this out.