Question

I’m trying to create an OpenLayers UI with two basic capabilities:

• there are fixed features on the map, and users get additional information on the page (not popups on the map) when they hover over a fixed feature;

• there is one draggable reference point, which a user can move around the map.

I’ve currently got each of these working independently. I have two vector layers, one for fixed features and one for the draggable feature. The first layer has a OL.Control.SelectFeature control with {hover:true}, the second has a OL.Control.DragFeature control. However, when I enable the DragFeature control, the SelectFeature control no longer gets any events when I mouse over the fixed features. Conversely, if I raise the z-index of the fixed-features layer (as suggested here) the draggable feature cannot be dragged. That suggests that only the topmost layer is available to user interaction.

I assume I’m making a fairly basic mistake here. How do I allow the user to interact with the features on two layers? Or, alternatively, is there a better way of designing the user experience I outllned above?

The other alternative I can see is that I put both types of feature on one layer, and somehow prevent the fixed features from responding to drag interaction. However, looking through the OpenLayers API, I can’t see any obvious way of getting the DragFeature control to abandon a drag interaction once intiated by the user.

Answer 1

OK, found a solution to this: the SelectFeature control needs to be attached to both layers, and the hover event handler then checks to see if the feature is selectable. The draggable feature remains on a separate layer, so it is the only draggable object. This posting was helpful in figuring out the answer.