Could not find symbol 'method'

The method method is a member of Toybox.Lang.Object. In order to use it you need to call it on an object instance of a class that inherits (explicitly or implicitly) from that class. When you write method(:receiveWeather) that is equivalent to writing self.method(:receiveWeather) but if there is no self, it can't work.

Developers typically don't realize this and they try to use method from within a function defined at module (or global) scope. For this to work, you could move your function into a class, or you could explicitly create the Lang.Method object like so:

// i'm assuming that receiveWeather is a function defined at global scope
var callable = new Lang.Method($, :receiveWeather);

thank you very much for your explanation! I get it!

I put the exemple in case someone wants to see it.

function makeRequest(lat, lng,apiKey) {
var UNITS=(Sys.getDeviceSettings().temperatureUnits==Sys.UNIT_STATUTE) ? "imperial" : "metric";
var url ="">api.openweathermap.org/.../weather";
var param={
"lat" => lat,
"lon"=>lng,
"appid"=>apiKey,
"units" => UNITS};
var options = {
:methods => Communications.HTTP_REQUEST_METHOD_GET,
:headers => {"Content-Type" => Communications.REQUEST_CONTENT_TYPE_URL_ENCODED},
:responseType => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON
};

var callable = new Lang.Method($, :receiveWeather);
Communications.makeWebRequest(
url,
param,
options,
callable);

}