Trouble adding event Listener on Drupal Gmap map

Question

I'm trying to write a Drupal module that will add UTM coordinate fields to a location form, such that they'll interact properly with the GMap map as well as the Latitude and Longitude fields - i.e. when the map is clicked, the UTM coordinates get calculated and populated along with the Lat/Long ones, and if the Lat/Long coordinates are changed by typing in the fields, the UTM coordinates change also, as well as the map, and vice versa.

I have the translation and everything else working except for clicking the map. I'm trying to add a Listener to the map so that when it's clicked, a change event will get triggered on the lat/long fields, which would in turn trigger the updating of the UTM fields. But, I can't seem to get the Listener to work. here's what I have so far (this is a snippet of my js file for my module, location_utm.js):

$(document).ready(function() {
    var themap = document.getElementById("gmap-auto1map-gmap0");

    Drupal.gmap.addHandler('gmap', function (themap) {
      var obj = this;

      var clickListener = GEvent.addListener(obj, "click", function() {           

         /* when the map gets clicked, trigger change event on the lat/long 
          fields so that the utm fields get updated too.   */
         $('#gmap-auto1map-locpick_longitude0').change();
         $('#gmap-auto1map-locpick_latitude0').change();



      });
   });
});

I've tried a lot of different slight variations of this code but can't seem to get it right. I appreciate any advice.

Answer 1

Please see the code comments:

if (GBrowserIsCompatible()) 
{
  Drupal.gmap.addHandler('gmap', function(elem, context) {
    var gmap = this;

    // Note: GMap module does not support solely
    // "locpickchange_dragend" and "locpickchange_click" events
    // by default. It combines map clicks, marker drag and
    // dragend events in an custom event called "locpickchange". 
    // Binding on those said solely triggers relies on a GMap
    // locpick widget patch which is included.
    //
    gmap.bind('locpickchange', function(context) {

    // Note: The coordinations stored in gmap.vars.latitude and
    // gmap.vars.longitude are for the previous location of the
    // locpicker marker, we need to use gmap.locpick_coord which
    // is pretty live!
    //
    if (gmap.locpick_coord) {

      // TODO: Implement the logic.
      // Current latitude: gmap.locpick_coord.lat()
      // Curren longitude: gmap.locpick_coord.lng()

    }
  });
}

In case that you want to use locpickchange_click & locpickchange_dragend, here is the dirty GMap module's patch:

From 2fb5a1ca71e1470e5413f10fb83ce959cd1d8634 Mon Sep 17 00:00:00 2001
From: Sepehr Lajevardi <me@sepehr.ws>
Date: Fri, 8 Jul 2011 14:38:27 +0430
Subject: [PATCH] Extends the locpick widget event system by adding
 lockpickchange_click and locpickchange_dragend custom
 events.

---
 js/locpick.js |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/js/locpick.js b/js/locpick.js
index d5aae9c..7c207f9 100644
--- a/js/locpick.js
+++ b/js/locpick.js
@@ -16,6 +16,18 @@ Drupal.gmap.addHandler('gmap', function (elem) {
     }
   });

+  // Bind triggering of a map click on our custom events.
+  obj.bind("locpickchange_dragend", function () {
+    if (obj.locpick_coord) {
+      GEvent.trigger(obj.map, "click", null, obj.locpick_coord);
+    }
+  });
+  obj.bind("locpickchange_click", function () {
+    if (obj.locpick_coord) {
+      GEvent.trigger(obj.map, "click", null, obj.locpick_coord);
+    }
+  });
+
   obj.bind("locpickremove", function () {
     obj.map.removeOverlay(obj.locpick_point);
     obj.locpick_coord = null;
@@ -40,10 +52,16 @@ Drupal.gmap.addHandler('gmap', function (elem) {
           GEvent.addListener(obj.locpick_point, 'dragend', function () {
             obj.locpick_coord = obj.locpick_point.getLatLng();
             obj.change('locpickchange', binding);
+            // Also trigger a locpickchange_dragend event
+            // so we can bind on just marker dragends.
+            obj.change('locpickchange_dragend', binding);
           });
           obj.locpick_coord = point;
           obj.map.panTo(point);
           obj.change('locpickchange', binding);
+          // Also trigger a locpickchange_click event
+          // so we can bind on just map clicks.
+          obj.change('locpickchange_click', binding);
         }
         else {
           // Unsetting the location
-- 
1.7.6