How to add a popup to a vector in OpenLayers?

Question

In a previous version of my program, I used markers to mark points on the map. In the current version, I had to switch from markers to vectors , because I need additional flexibility. In solving markers, I used the function below to add a popup to the marker:

 function createPopupBoxFeature(vector, lonLat, description) { var feature = new OpenLayers.Feature(vector, lonLat); feature.closeBox = true; feature.popupClass = OpenLayers.Class(OpenLayers.Popup.AnchoredBubble, { "autoSize": true }); feature.data.popupContentHTML = description; vector.events.register("mousedown", feature, function(evt) { if (this.popup == null) { this.popup = this.createPopup(this.closeBox); map.addPopup(this.popup); this.popup.show(); } else { this.popup.toggle(); } OpenLayers.Event.stop(evt); }); return feature; } 

But it no longer works for vectors because they do not have the events property. How to fix it?

Answer 1

I decided it myself. Here's how:

 // Used to display the dialog popup var selectControl; var selectedFeature; 

Add SelectFeature Function

  selectControl = new OpenLayers.Control.SelectFeature(vectorLayer, { onSelect: onFeatureSelect, onUnselect: onFeatureUnselect }); map.addControl(selectControl); selectControl.activate(); 

Event handlers

 function onPopupClose(evt) { selectControl.unselect(selectedFeature); } function onPopupFeatureSelect(feature) { selectedFeature = feature; popup = new OpenLayers.Popup.FramedCloud("chicken", feature.geometry.getBounds().getCenterLonLat(), null, feature.name, null, true, onPopupClose); popup.panMapIfOutOfView = true; popup.autoSize = true; feature.popup = popup; map.addPopup(popup); } function onPopupFeatureUnselect(feature) { map.removePopup(feature.popup); feature.popup.destroy(); feature.popup = null; } 

Save the contents of the popup in the vector name. There might be a better solution, but I don't care. Adding pop-ups to vectors is already quite complicated.

 vector.name = "Your popup content"; 

Answer 2

Actually the official way to do this:

(Note: some of the variables were not declared in these snippets: longt, lat, map)

http://dev.openlayers.org/examples/light-basic.html

 //Step 1 - create the vector layer var vectorLayer = new OpenLayers.Layer.Vector("ExampleLayer",{ eventListeners:{ 'featureselected':function(evt){ var feature = evt.feature; var popup = new OpenLayers.Popup.FramedCloud("popup", OpenLayers.LonLat.fromString(feature.geometry.toShortString()), null, feature.attributes.message+"<br>"+feature.attributes.location, null, true, null ); popup.autoSize = true; popup.maxSize = new OpenLayers.Size(400,800); popup.fixedRelativePosition = true; feature.popup = popup; map.addPopup(popup); }, 'featureunselected':function(evt){ var feature = evt.feature; map.removePopup(feature.popup); feature.popup.destroy(); feature.popup = null; } } }); //Step 2 - add feature to layer var p = new OpenLayers.Geometry.Point(longt, lat); var feature = new OpenLayers.Feature.Vector( p.transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject()), {message:'foo', location:'bar'}, {externalGraphic: '../img/marker.png', graphicHeight: 21, graphicWidth: 16} ); vectorLayer.addFeatures(feature); //Step 3 - create the selectFeature control var selector = new OpenLayers.Control.SelectFeature(vectorLayer,{ hover:true, autoActivate:true }); //Step 4 - add the layer and control to the map map.addControl(selector); map.addLayer(vectorLayer);