topic Re: Change layer definitions properly repeatedly in ArcGIS JavaScript Maps SDK Questions

Change layer definitions properly repeatedly

PitersonPaulgek — Tue, 22 Nov 2016 06:13:35 GMT

Hi,

We do time series "manually" for some reasons.

We created recursive function.

The issue is with changing of layer definitions repeatedly. The layer disappears between first and second (recursive) call to the function.

var isPlay = true;
var layerDefinitionsTS = [];

var currentTimeSeriesLayer = (initialized outside);
function PlayTimeSeries(startYear, endYear, timeIntervalMilliSeconds) {
   if (startYear == endYear)
      return;
   if (isPlay == false)
      return;
//layerDefinitionsTS = [];
      currentTimeSeriesLayer.setLayerDefinitions(null, true);

layerDefinitionsTS[currentTimeSeriesLayer.visibleLayers[0]] = "Year = " + startYear;
currentTimeSeriesLayer.setLayerDefinitions(layerDefinitionsTS, false);

      setTimeout(function (startYear, endYear, timeIntervalMilliSeconds) {
      startYear = startYear;
      console.log("Year: " + startYear);

startYear = startYear + 1;

PlayTimeSeries(startYear, endYear, timeIntervalMilliSeconds);
}, timeIntervalMilliSeconds, startYear, endYear, timeIntervalMilliSeconds);
};

Any help will be appreciated.

Re: Change layer definitions properly repeatedly

FC_Basson — Fri, 10 Dec 2021 21:30:08 GMT

Setting timeouts within the function scope might not be the best option. You should also create handlers for each timeout which you can clear before updating the layer definitions e.g.

...

var toHandler = setTimeout( function(...){
   ...
   clearTimeout(toHandler);
})‍‍‍‍‍‍‍‍

Why not consider time-enabling your layer and displaying it with a Time Slider (TimeSlider | API Reference | ArcGIS API for JavaScript 3.18)?

Re: Change layer definitions properly repeatedly

PitersonPaulgek — Tue, 22 Nov 2016 06:31:17 GMT

Thank you for response FC Basson,

In your code, where is setLayerDefinition()?

We cannot use ESRI widget because the custom requirements for time slider UI.

Re: Change layer definitions properly repeatedly

FC_Basson — Tue, 22 Nov 2016 07:18:26 GMT

Same line as yours. Seeing that you are calling the PlayTimeSeries function recursively, you can call the clearTimeout method just before the setTimeout method.

Re: Change layer definitions properly repeatedly

PitersonPaulgek — Fri, 10 Dec 2021 21:30:10 GMT

FCBasson,
Should we use a global variable "toHandler" to clearTimeout(toHandler)?

Like this? -

var isPlay = true;
var layerDefinitionsTS = [];
var currentTimeSeriesLayer = (initialized outside);
var toHandler;

function PlayTimeSeries(startYear, endYear, timeIntervalMilliSeconds) {
   if (startYear == endYear)
      return;
   if (isPlay == false)
      return;
//layerDefinitionsTS = [];
      currentTimeSeriesLayer.setLayerDefinitions(null, true);
      layerDefinitionsTS[currentTimeSeriesLayer.visibleLayers[0]] = "Year = " + startYear;
      currentTimeSeriesLayer.setLayerDefinitions(layerDefinitionsTS, false);
      clearTimeout(toHandler);
      toHandler = setTimeout(function (startYear, endYear, timeIntervalMilliSeconds) {
      startYear = startYear;
      console.log("Year: " + startYear);
      startYear = startYear + 1;
      PlayTimeSeries(startYear, endYear, timeIntervalMilliSeconds);
   }, timeIntervalMilliSeconds, startYear, endYear, timeIntervalMilliSeconds);
};

Re: Change layer definitions properly repeatedly

PitersonPaulgek — Tue, 22 Nov 2016 23:53:19 GMT

I tried - the layer is not visible.

I can see the layer in the map.layerIDs.

I can get the count by queryTask.executeForCount() after applying layer definitions - each time different.

What is the reason the layer is not visible? How to check it?