OpenLayers 3 select style - openlayers-3

Question

In OL2 I was able to specify a "select" style in the style definition. In OL3 this doesn't seem to exist. If I understand it correctly, I can set a style for the select interaction. However, this likely won't work in my case since every layer has a unique "selected" style. Am I mistaken in my assessment of the capability? Is there another/optimal way to do this in OL3?

Answer 1

Let's assume that you have a style parameter stored in each ol.Feature, you can add a ol.style.StyleFunction to your ol.interaction.Select and return a style based on this parameter. Like so:
var styles = {
'route': new ol.style.Style({
stroke: new ol.style.Stroke({
width: 6,
color: [237, 212, 0, 0.8]
})
}),
'icon': new ol.style.Style({
image: new ol.style.Icon({
anchor: [0.5, 1],
src: 'pin.png'
})
}),
'geoMarker': new ol.style.Style({
image: new ol.style.Circle({
radius: 7,
snapToPixel: false,
fill: new ol.style.Fill({color: 'black'}),
stroke: new ol.style.Stroke({
color: 'white',
width: 2
})
})
})
};
var select = new ol.interaction.Select({
style: function(feature, resolution) {
return [styles[feature.get('style_parameter')]];
}
});
And your feature would be like:
var geoMarker = new ol.Feature({
style_parameter: 'geoMarker',
geometry: new ol.geom.Point([0,0])
});

Answer 2

I know this a very old thread, but since I haven't been able to find a clear solution to this particular problem yet, I still deem it fit to post mine. Not sure how it holds up with a large number of layers and features, but this is the most elegant and concise solution I could come up with.
BTW: I'm using the latest version of OpenLayers, which at the moment is 6.3.1.
var map = new ol.Map({
...
layers: [
new ol.layer.Vector({
...
// Default style for layer1
style: default1,
// Hover style for layer1 (custom property)
hoverStyle: hover1,
// Selected style for layer1 (custom property)
selectedStyle: selected1
}),
new ol.layer.Vector({
...
// Default style for layer2
style: default2,
// Hover style for layer2 (custom property)
hoverStyle: hover2,
// Selected style for layer2 (custom property)
selectedStyle: selected2
})
],
...
});
var hoverInteraction = new ol.interaction.Select({
condition: ol.events.condition.pointerMove,
style: function(feature) {
var layer = hoverInteraction.getLayer(feature);
return layer.values_.hoverStyle;
}
});
map.addInteraction(hoverInteraction);
var selectInteraction = new ol.interaction.Select({
condition: ol.events.condition.click,
style: function(feature) {
var layer = selectInteraction.getLayer(feature);
return layer.values_.selectedStyle;
}
});