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Determining if a layer is a baselayer in layer-add-result event

kenbuja

I am adding several layers (both dynamic and tiled) programmatically to my map. In the layer-add-result event, I am setting the visibility to false and the visibleLayers to -1 for all the layers.

map.on("layer-add-result", function (addedLayer) {
    addedLayer.layer.setVisibility(false);
    addedLayer.layer.setVisibleLayers([-1]);
});

However, when I create the map with a basemap, the basemap layer( or layers, since some basemaps have multiple layers) will also fire this event. Since I want to keep the basemap visible, how can I determine if the layer a basemap?

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Accepted answers

YungKaiChin

There may be a few ways to find that info:

In general, the base layer will be the very first layer (index = 0) in map.layerIds.

Thus, var layer = map.layerIds[0] by default will get you the basemap.

If you have more than one basemap, you can find an array of basemap with basemapLayerIds property.

So, var arrLayers = map.basemapLayerIds will do.

Another way to find the current basemap:

var tempMap = document.getElementById("map");

console.log(tempMap.dataset.basemap);

(Note: I didn't check my spelling on these, so they may not be exact.)

All comments

YungKaiChin

There may be a few ways to find that info:

In general, the base layer will be the very first layer (index = 0) in map.layerIds.

Thus, var layer = map.layerIds[0] by default will get you the basemap.

If you have more than one basemap, you can find an array of basemap with basemapLayerIds property.

So, var arrLayers = map.basemapLayerIds will do.

Another way to find the current basemap:

var tempMap = document.getElementById("map");

console.log(tempMap.dataset.basemap);

(Note: I didn't check my spelling on these, so they may not be exact.)

RobertScheitlin__GISP

Ken,

Why not use Object.prototype.toString.call(addedLayer.layer)?

kenbuja

Thanks, I ended up using this code

map.on("layer-add-result", function (addedLayer) {
    var isBaseLayer = false;
    array.forEach(map.basemapLayerIds, function (baseLayer) {
        if (addedLayer.layer.id === baseLayer) { isBaseLayer = true; }
    })
    if (isBaseLayer) { return; }
    addedLayer.layer.setVisibility(false);
    if (addedLayer.layer.declaredClass !== "esri.layers.ArcGISTiledMapServiceLayer") {
        addedLayer.layer.setVisibleLayers([-1]);
    }
});

kenbuja

Robert Scheitlin, GISP‌I must be missing something‌. I tried that line but only got back the string "[object Object]"

var test = Object.prototype.toString.call(addedLayer.layer);

RobertScheitlin__GISP

Ken,

Sorry I thought that this was a method of getting the exact object class name, but It will only give you the JavaScript Basic types (i.e Object.prototype.toString.call(new Date); // "[object Date]").

YungKaiChin

Or be lazy ..

if ( map.basemapLayerIds.indexOf(addLayer.layer.id) == -1) { // not baselayer

// do whatever

}

kenbuja

True, although it would be better to use the dojo/_base/array indexOf method if there are clients who are using IE 8 or older.

map.on("layer-add-result", function (addedLayer) {
    if (array.indexOf(map.basemapLayerIds, addedLayer.layer.id) === -1) {
        addedLayer.layer.setVisibility(false);
        if (addedLayer.layer.declaredClass !== "esri.layers.ArcGISTiledMapServiceLayer") {
           addedLayer.layer.setVisibleLayers([-1]);
        }
    }
});

kenbuja

I thought this was going to be the answer, but it turns out that if I change the basemap using the BasemapGallery dijit, this won't work. I discovered that map.basemapLayerIds does not change when another basemap is selected, even though the map.layerIds does change.

khutchins

Could you use the basemapGallery.getSelected method to get the currently selected basemap from the gallery and use that id to compare?

kenbuja

The basemap's id does not correspond to the map's layer ids of the basemap...if that makes sense. This JSBin will show that.

kenbuja

The problem with map.basemapLayerIds has been deemed a bug (BUG-000083794).

What I ended up doing is to put in a Boolean so that this code only runs when the map is initialized.

map.on("layer-add-result", function (addedLayer) {
    if (initializing) {
        if (array.indexOf(map.basemapLayerIds, addedLayer.layer.id) === -1) {
            if (addedLayer.layer !== layerDynamic && addedLayer.layer !== layerResultsGraphic) {
                addedLayer.layer.setVisibility(false);
                if (addedLayer.layer.declaredClass !== "esri.layers.ArcGISTiledMapServiceLayer") { addedLayer.layer.setVisibleLayers([-1]); }
            }
        }
    }
});

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