topic Re: Legend title based on variable needs to refresh too in ArcGIS JavaScript Maps SDK Questions

Legend title based on variable needs to refresh too

TracySchloss — Tue, 26 Aug 2014 16:05:50 GMT

I have a project that let's the user change which attribute field is used in the display. It's based on the sample https://developers.arcgis.com/javascript/jssamples/renderer_dynamic_layer_change_attribute.html For the legend, I'm creating it if it doesn't exist, but if it does, then I just want it to refresh. My problem is that the title is based on a variable, defined based on the change event of the FilteringSelect list of fields. When I change the field, the legend itself updates, but it still has the title from its initial creation.

Can I change just the title? It doesn't seem to be honoring my title definition when I specify legend.refresh(). In this example, fields is the array of attributes from my layer and fieldChoice is the selected item from the FilteringSelect.

  domConstruct.empty("legendDiv");
        if (!legend){       
         legend = new Legend({
            map: map,
            layerInfos: [{ "layer": featureLayer, "title": fields[fieldChoice] }]
          },"legendDiv");
          legend.startup();
          }else{
            legend.refresh();
            
          }

Re: Legend title based on variable needs to refresh too

MirceaMaierean — Tue, 26 Aug 2014 16:54:34 GMT

Ran in the same problem while creating a web map for my Capstone project but using the Generate Render Sample (Generate renderer | ArcGIS API for JavaScript )

I got to solve the problem by adding the "app." back into it and setting the "var app []" as a global variable.

function createLegend(map, fl) {
  // destroy previous legend, if present
  if ( app.hasOwnProperty("legend") ) {
app.legend.destroy();
  domConstruct.destroy(dojo.byId("legendDiv"));
}
  // create a new div for the legend
  var legendDiv = domConstruct.create("div", {
  id: "legendDiv"
  }, dom.byId("legendWrapper"));

  app.legend = new Legend({
  map : map,
  layerInfos : [{
  layer : fl,
  title : "Census Attribute: " + fields[currentAttribute]
  }]
  }, legendDiv);
  app.legend.startup();
   
  }

Re: Legend title based on variable needs to refresh too

TracySchloss — Tue, 26 Aug 2014 19:28:27 GMT

That's not just changing the title, it's getting rid of the entire legend and recreating it every time. I'd like to avoid this. What I did was add another div right above the legend, calling it legendTitle. Then I styled the legend so that its default title wouldn't display at all.

.esriLegendServiceLabel {
   display:none;
}

Then I set the content of my new legendTitle to be the field name like I wanted.

Re: Legend title based on variable needs to refresh too

KellyHutchins — Wed, 27 Aug 2014 00:20:24 GMT

If I understand the question correctly then calling legend.refresh and providing the updated layer info with the new title should update the title in the legend.

legend.refresh([{

layer: featureLayer,

title: "Updated layer name"

}]);

Re: Legend title based on variable needs to refresh too

TracySchloss — Wed, 27 Aug 2014 13:12:41 GMT

Your way worked and is more right then my workaround method, so I changed which one is marked as Correct Answer.