topic Re: underbelly of .setVisibility() method for Feature Layer? in ArcGIS JavaScript Maps SDK Questions

underbelly of .setVisibility() method for Feature Layer?

Anonymous User — Mon, 11 Aug 2014 23:46:55 GMT

Hi - I am struggling with what I believed was asynchronous behavior from the setVisibility method on a feature layer. I have a huge feature layer that, to avoid issues, has visibility set to false on load. After clearing the layer's graphics and adding a new, smaller set of graphics, I was setting visibility to 'true'. However all of the thousands of feature graphics kept showing up anyways. I tried using Dojo deferreds and rearranging when I changed visibility to no avail. The only thing that worked was changing the visibility, letting the entire map update, then clearing the graphics.

console.log('set visibility');
fl.setVisibility(true);
var wait = on(map, 'update-end', function() {
   // Function to clear graphics 
   fl.clear();
   fl.add(graphicSubset);
   wait.remove();
});

However, this still flashes all of the layer's graphics before clearing them. Suspending drawing on the feature layer did not stop the flashing problem, and if I change the graphics first then wait and change visibility, it overrides the changes I made and loads the original layer's thousands of graphics when it is made visible.

So I am wondering what setVisibility() is doing to override what I input as graphics. I can see the altered layer with 28 features in the console log if I do not change visibility and the visibility is set to false, but if I change the graphics to the 28 features (results from a query) then set visibility to true after all updates are done, 1500 graphics are returned from the original feature layer even though I cleared them all...

Re: underbelly of .setVisibility() method for Feature Layer?

OwenEarley — Tue, 12 Aug 2014 00:42:05 GMT

What mode are you using when adding your feature layer? - MODE_AUTO, MODE_ONDEMAND, MODE_SELECTION, MODE_SNAPSHOP

This setting can impact what features are loaded and when they are loaded.

Do you have the full page code available?

Re: underbelly of .setVisibility() method for Feature Layer?

RiyasDeen — Tue, 12 Aug 2014 02:09:47 GMT

Did you try using setDefinitionExpression(expression) on the feature layer?

featurelayer | API Reference | ArcGIS API for JavaScript‌

Re: underbelly of .setVisibility() method for Feature Layer?

Anonymous User — Thu, 14 Aug 2014 18:52:22 GMT

Thanks for the replies. I have both an ONDEMAND and SNAPSHOT feature layer I am doing this for. I will try to put together code to share but right now the application is so huge it would drive you bonkers to try to follow.

setDefinitionExpression is helpful, except I need to subset data by OBJECTID so that may get unwieldy. My sense is the syntax would be 'OBJECTID=1 and OBJECTID=2 and..."etc

Re: underbelly of .setVisibility() method for Feature Layer?

RobertScheitlin__GISP — Thu, 14 Aug 2014 19:01:27 GMT

Sarah,

If you are going to have a long list of ObjectIds the the better SQL will look like this:

OBJECTID IN (1,2,4,6,7)

Re: underbelly of .setVisibility() method for Feature Layer?

JohnGrayson — Thu, 14 Aug 2014 19:29:03 GMT

Sarah, specific to the definition expression issue, you can use the IN operator in your where clause:

ObjectID IN (33,55,56,222)

It could go something kind of like this:

var objectIdField = featureLayer.objectIdField;
var objectIds = array.map(features,function(feature){
  return feature.attributes[objectIdField];
});
var whereClause = lang.replace("{0} IN ({1})",[objectIdField,objectIds.join(",")]);
featureLayer.setDefinitionExpression(whereClause);

Re: underbelly of .setVisibility() method for Feature Layer?

Anonymous User — Fri, 15 Aug 2014 21:52:56 GMT

Thanks everyone, I have finally managed a full workaround, though I still do not understand what was going on with the .setVisibility() method overriding my graphics. I chose to use setDefinitionExpression() because then 'ONDEMAND' feature layers did not fully redraw and have to be hidden after every map pan event, etc. I also used a QueryTask rather than the queryIds method of a feature layer to grab the objectids I needed since it queries the server and not client side, where the ids were being limited by the definition expression..

I have the 'visibility : true' set for all layers involved
I make them all MODE_ONDEMAND (SNAPSHOT mode was weirdly saving previous graphics from prior definition expressions sometimes)
I set their definition expression on load to something that returns null so that no features are displayed. This gets around the setVisibility method problem, so I never have to change it.
I run a query that gathers the objectids I need to display
I set the definition expression using those objectids to display the specific data I need to show

Re: underbelly of .setVisibility() method for Feature Layer?

Anonymous User — Fri, 15 Aug 2014 21:54:36 GMT

Thanks for that 'objectIdField' property tip John, I had not noticed that before.