Question

Im trying to get the toggle switch to DISABLE and STOP the geolocation routine…

i get null object error when geo is set to new Geolocation — what am I missing here?

        private function gogeo():void
        {
            if (Geolocation.isSupported)
            {
                var geo:Geolocation = new Geolocation();
                geo.setRequestedUpdateInterval(2000);
                geo.addEventListener(GeolocationEvent.UPDATE, geolocationUpdateHandler);
            }
            else
            {
                trace("No geolocation support.");
            }   
        }



        private function geolocationUpdateHandler(event:GeolocationEvent):void
        {
            trace("lat:" + event.latitude.toString() + " - ");
            trace("long:" + event.longitude.toString() + "° - ");
            trace("Accuracy:" + event.horizontalAccuracy.toString() + " m");

        }
        protected function toggleswitch1_changeHandler(event:Event):void
        {

            if (toggleswitch1.selected == false) {
            trace("The function should STOP"); 

            geo.removeEventListener(GeolocationEvent.UPDATE, geolocationUpdateHandler);
            geo = null;

        } else {
            trace("The function should RESTART");

            geo = new Geolocation();
            geo.addEventListener(GeolocationEvent.UPDATE, geolocationUpdateHandler);
        }
        }

Answer 1

Define geo outside of the function:

private var geo:GeoLocation;

private function gogeo():void
{
    if (Geolocation.isSupported)
    {
        geo = new Geolocation();
        geo.setRequestedUpdateInterval(2000);
        geo.addEventListener(GeolocationEvent.UPDATE, geolocationUpdateHandler);
    }
    else
    {
        trace("No geolocation support.");
    }   
}

variables are only available within their ‘scope’ – eg: if you define a variable inside a function, it is only available from within that function

edit:

To define geo as global:

In top level of your app (ie in the main mxml file), add a public declaration:

public var geo:GeoLocation;

And then access it from anywhere in your app using:

(FlexGlobals.topLevelApplication as MyAppClass).geo

instead of just “geo”; where MyAppClass is the name of your app (ie: the name of your main mxml class)