redraw openlayers vector layer

Question

I want to redraw an OpenLayers vector.

my html button:

<button id="refresh" type="button">Refresh</button>

and my jquery functions to redraw the layer, the parksLayer in the refresh function is logging as false:

function refresh() {
    parksLayer.redraw(true);
}

function bind(){
    $("#refresh").bind("click", refresh);
}

and my map, I want to redraw the ParksLayer:

        map = new OpenLayers.Map({
            div: "map",
            layers: [
                new OpenLayers.Layer.OSM(),
                parksLayer
            ]
        });

UPDATE

Thanks for the help, my vector layer is defined like this:

function changeme(avalue){
        parksLayer = new OpenLayers.Layer.Vector("Parks", {
            projection: new OpenLayers.Projection("EPSG:4326"),
            strategies: [new OpenLayers.Strategy.Fixed()],
            protocol: new OpenLayers.Protocol.Script({
                url: "http://my.cartodb.com/api/v2/sql",
                params: {
        q: "SELECT * FROM activities where type_code is not null"+" "+avalue,
        format: "geojson"
    },
                format: new OpenLayers.Format.GeoJSON({
                    ignoreExtraDims: true
                }),
                callbackKey: "callback"
            }),
        });  
    }

I have a form that changes avalue dynamically which changes the GeoJSON query, so if I could redraw the parksLayer I would be left with a new selection from the layer.

Answer 1

If I read the Openlayers API, redraw function does not use any parameters... You should try to call redraw() without putting "true" as a parameter...

Openlayers API: redraw: function() Redraws the layer. Returns true if the layer was redrawn, false if not.

Regards

Etienne

Answer 2

I have problems with redraw() too and use this.

VecLayer.redraw(true);
VecLayer.refresh({force: true});

Answer 3

Here's one for a KML Format, but it's very easily adapted as you can see

   var refresh = new OpenLayers.Strategy.Refresh({force: true, active: true});

   var protocol = new OpenLayers.Protocol.HTTP({
         url: "http://my_data.source.com",
            format: new OpenLayers.Format.KML({
                  extractStyles: false,
                  extractAttributes: true
               })
            });

   mylayer = new OpenLayers.Layer.Vector("MyLayerName", {
            strategies: [new OpenLayers.Strategy.Fixed(), refresh],
            protocol: protocol
   });

Then to redraw/redownload data you do :

refresh.refresh();