topic Re: Legend creation/destroy in ArcGIS JavaScript Maps SDK Questions

Legend creation/destroy

MatthewBorr — Mon, 18 Aug 2014 14:11:10 GMT

Hi!

I'm stuck on this legend creation.

I am creating a legend for a unique renderer for feature service "ct" in function funcall (called by a button) It creates a choropleth map.

The user then deletes the new map (in function funcalldel), and can create another with a new renderer, and so on. (the code shown is truncated for clarity)

I can create a legend the first time, but I can't seem to use destroy method or any other way to delete the existing legend and create a new one.

function funcall(radioOne,radioTwo,radiohs,radioadult){     dijit.byId("create").setAttribute('disabled', true);              //map.removeLayer(ct)       ct = new esri.layers.FeatureLayer("http://gis-server.cc.wmich.edu/harcgis/rest/services/hdream/tract_sex_age2/MapServer/0",{         mode: esri.layers.FeatureLayer.MODE_ONDEMAND,         opacity: .7,         outFields: ["*"],  });       else if (mandf.checked && sen.checked) {                      var maxval=1049;     var field="MF_Senior_ ";                          var tracttemplate=new esri.InfoTemplate();        tracttemplate.setTitle("<b>Male/Female Senior (65+)</b><br>");         tracttemplate.setContent("<b>Population: </b>${MF_Senior_ }"                     );                     ct.setInfoTemplate(tracttemplate);                  }            var renderer = new esri.renderer.SimpleRenderer(new esri.symbol.SimpleFillSymbol().setOutline(new esri.symbol.SimpleLineSymbol().setWidth(0.5)));           renderer.setColorInfo({             field: field,             minDataValue: 0,             maxDataValue: maxval,             colors: [               new esri.Color([255, 255, 255]),               new esri.Color([0, 42, 255])             ]           });           var legendLayers = [];                     ct.setRenderer(renderer);                    map.addLayer(ct);         map.reorderLayer(ct,15);                legendLayers.push({layer:ct,title:'Population'});           var legendDijit = new esri.dijit.Legend({                     map: map,             layerInfos:legendLayers            }, "legendDiv");            legendDijit.startup();       };    function funcalldel(legendDijit){            if (ct.loaded = 'true') {map.removeLayer(ct)};     dijit.byId("create").setAttribute('disabled', false);           };                   dojo.ready(init);   </script>

I'm sure I need to destroy the legend somewhere. I tried that in "funcalldel", but an error appear because the variable "legendDijit" is not recognized.

Maybe use an if..then else?

Thanks!

Re: Legend creation/destroy

TimWitt2 — Mon, 18 Aug 2014 14:30:14 GMT

The following code doesn't work?

legendDijit.destroy();

what if you also add the following ?

dojo.byId(Name of the Div your legend is displayed in).innerHTML='';

Let me know if that helps!

Tim

Re: Legend creation/destroy

MatthewBorr — Mon, 18 Aug 2014 14:40:11 GMT

Thanks,

legendDijit.destroy will not work in the "funcalldel" function (where the user deletes the map) because when I run it, the variable legendDijit is not recognized and produces an error.

--------------------------

I inserted

dojo.byId("legendDiv").innerHTML='';

into the delete function, and it removed the legend, but I get an error when I try to create another map:

> Tried to register widget with id==legendDiv but that id is already registered

So I think I have to use legendDijit.destroy somewhere, but not sure how.

Re: Legend creation/destroy

TimWitt2 — Mon, 18 Aug 2014 14:42:09 GMT

Make sure at the beginning of your code type

var legendDijit;

and remove the var infront of the legendDijit in your function.

The way you have it the legendDijit is not a global variable.

Re: Legend creation/destroy

MatthewBorr — Mon, 18 Aug 2014 14:57:34 GMT

Ok, using the correct variable scope, I can use the destroy method, but now after I use the delete function, when creating another map, I get these two errors when I call the funcall function again:

TypeError: p.byId(...) is null

and

TypeError: Unable to draw graphic (geometry:null, symbol:null): c is null

Thanks again for your help

Re: Legend creation/destroy

TimWitt2 — Mon, 18 Aug 2014 15:04:20 GMT

Did you incorporate this? dojo.byId("legendDiv").innerHTML='';

If so remove it, you don't need it. Maybe that will help?

Re: Legend creation/destroy

MatthewBorr — Mon, 18 Aug 2014 16:32:07 GMT

I removed it, still the same error. Can't seem to figure out what these errors mean.

What's strange is that it creates the map the first time, but after I delete and run funcall again, it throws the errror!

Re: Legend creation/destroy

TimWitt2 — Mon, 18 Aug 2014 17:00:24 GMT

Can you post your full code or add it to a jsfiddle?

Re: Legend creation/destroy

MatthewBorr — Mon, 18 Aug 2014 17:25:04 GMT

HDream Online Data Map‌

The variable selector is at the bottom of the left pane. Some combinations have no data attached.

Use female/child bearing and female/adult combinations to create the choropleth maps. They have data attached.

Thx again.

Re: Legend creation/destroy

MatthewBorr — Tue, 19 Aug 2014 16:02:05 GMT

Are you able to get to the code? It's (probably unnecessarily) long, but the code in question is at the bottom of the <script> section.

Re: Legend creation/destroy

TimWitt2 — Tue, 19 Aug 2014 16:07:15 GMT

I was able to look, but couldn;t figure out how to fix it.

It seems that when you destroy the legend widget it also destroys the placement. I think if you could create your placement in your function, it might work.

Re: Legend creation/destroy

MatthewBorr — Tue, 19 Aug 2014 17:49:21 GMT

Thanks for trying Tim,

I'll keep trying, there must be a way to do this. Anyone else have any suggestions?