Is there an event for when features are selected in OpenLayers 3?

Question

http://ol3js.org/en/master/examples/select-features.html

Given the above examples, what extension points are there for hooking into when features are selected?

Osrock

Answer 1

You can bind a precompose event to your layer when a singleclick event is triggered on your map. From here you can dispatch a change event on your select interaction.

yourmap.on('singleclick',function(event)){
    layer.once('precompose',function(event){
        yourSelectInteraction.dispatchChangeEvent();
    }
}

yourSelectInteraction.on('change',function(){
    //Do stuff with your selected features here
}

Permenter

Thanks, +1. Do you know why the change event is not dispatched automatically every time a feature is (un)selected ?? – Barrio

Answer 2

Here is a solution that might be more intuitive than Danny's, and also seems to be the "official" way, see this issue on ol3's GitHub.

Simply add the listener to the collection of selected features :

    mySelectInteraction.getFeatures().on('change:length', function(e) {
        if (e.target.getArray().length === 0) {
            alert("no selected feature");
        } else {
            var feature = e.target.item(0);
            alert(feature.getId()); //or do something better with the feature !
        }
    });

Barrio

As mentioned in the GitHub issue, you can also subscribe to the 'add' and 'remove' events on the features collection. – Suboxide

You can use e.target.getLength() instead of e.target.getArray().length – Thomasinathomasine

Answer 3

You want to use the featureselected event handler:

This example is on a Vector layer:

featuresLayer.events.on({
    'featureselected': function (e) {
        console.log(e);
    }
});

Lunula

is that openlayers 3? events is not defined. – Solidstate