Zooming through a Loop of Features

[TomLeMahieu]

I am trying to step through a set of selected features, zoom to the extent of the feature, do something with it and then go to the next feature and do the same.  I can't seem to trap the end of the zoom no matter what I do.  Does anybody have code that does this successfully.  It works fine for one.  It just doesn't work when I loop through a set of features.  Here's what I've tried:

printSingleParcelFeature: function (feature, callback) {
     var self = this;
     self.zoomSelectedOne(feature, function() {
          callback();
      });             
},

zoomSelectedOne: function(feature, callback) {    

     var gExt;

     var selectedExt;

     //Also tried 'zoom-end'.  That never works.       

     var mapZoomChange = this.map.on('extent-change', zoomHandler);

     function zoomHandler() {

            console.info("Extent Change");

            setTimeout(lang.hitch(this, function () {

                mapZoomChange.remove();

                callback();

            }), 1000);

      }

      gExt = feature.geometry.getExtent();

      if (gExt) {

            selectedExt = gExt.expand(this.zoomSelectExpand,true);

            this.map.setExtent(selectedExt);

            console.info("Set Extent: " + feature.attributes["PIN"]);

      }

},

My console results are basically this:

I also tried this, but again the extent only changes for the last one:

zoomSelectedOne: function (feature, callback) {       

var gExt;
var selectedExt;
gExt = feature.geometry.getExtent();
if (gExt) {
   selectedExt = gExt.expand(this.zoomSelectExpand,true);
   this.map.setExtent(selectedExt).then(callback());
} 
},

[TimWitt2]

Hey Tom,

Instead of waiting for the "extent-change" event to finish, use the featurelayer "update-end" event?

FeatureLayer | API Reference | ArcGIS API for JavaScript

Even though the extent is changed, i think your feature layer isn't ready yet?

Tim

[KellyHutchins · Accepted solution]

Tom LeMahieu​

One option would be to wait until setExtent is complete then do what you need to do then navigate to the next features extent.  Here's a jsbin that shows zooming to a feature, generating a printout, then zooming to the next feature.

JS Bin - Collaborative JavaScript Debugging

[TomLeMahieu]

Kelly & Tim,

Thanks for your responses.  Both helped get me on the right track.  It ended up that my problem was how I was stepping through the selected features. It wasn't getting to the callback until it had stepped through all the features.

Not working:

Working:

        for (var i = 0; i < numSelected; i++) {

            feature = features;

            self.printSoilErosionFeature(feature, function() {

                //nothing

            });

        }

        callback();

count = 0;

function processFeatures() {

   if (features.length > count) {

      var feature = features[count];

      self.printSingleParcelFeature(feature, processFeatures)

       count++;

   } else {

      callback();

   }

}

processFeatures();