Appcelerator Titanium - Reverse Geocoder and Variable Scope Issues

Question

I am trying to use the titanium reverseGeocoder but I am having a strange issue which I think is a "scope" issue. I can't quite understand why the last log call I make returns null values when I have defined the variables in that scope.

var win = Titanium.UI.currentWindow;
Ti.include('includes/db.js');

var city = null;
var country = null;

Titanium.Geolocation.reverseGeocoder(   Titanium.UI.currentWindow.latitude, 
                                        Titanium.UI.currentWindow.longitude, 
                                        function(evt) {

var places = evt.places;

if (places && places.length) {
city    = places[0].city;
country = places[0].country;    
}
Ti.API.log(city + ', ' + country); // <<< RETURNS CORRECT VALUES

});

Ti.API.log(city + ', ' + country); // <<< RETURNS NULL VALUES

Never used that library, although it looks asynchronous, so that would give it the *exact* same behaviour as an ajax call. Please see this question just closed: http://stackoverflow.com/questions/7833379/scope-of-javascript-variable — davin, Oct 20 '11 at 09:00
it's a similar situation, I need a way to only assign the variables once the geocoder has completed. — bagwaa, Oct 20 '11 at 09:36

score 1 · Accepted Answer · edited Jul 22 '13 at 21:58

This is an async call as Davin explained. You will have to call a function within the reverse geocode function.

A suggestion I can give you is to work event-based. Create events, and fire events. An example:

Titanium.UI.currentWindow.addEventListener('gotPlace',function(e){
    Ti.API.log(e.city); // shows city correctly
});

Titanium.Geolocation.reverseGeocoder(   Titanium.UI.currentWindow.latitude, 
                                        Titanium.UI.currentWindow.longitude, 
                                        function(evt) {

    var city, country, places = evt.places;

    if (places && places.length) {
        city    = places[0].city;
        country = places[0].country;    
    }
    Ti.API.log(city + ', ' + country); // <<< RETURNS CORRECT VALUES
    Titanium.UI.currentWindow.fireEvent('gotPlace',{'city': city, 'country': country});
});

thanks, this was useful - I ended up just making sure my calls were inside the event. — bagwaa, Oct 21 '11 at 14:56

Appcelerator Titanium - Reverse Geocoder and Variable Scope Issues

1 Answers1