Variables are being bound to the callback of a getCurrentLocation
function. Why isn't this closure working?
I apologize for the amount of code, but I think this is actually a problem
with AppMobi's getCurrentLocation function. Basically what happens is I
delegate a tap event to each list element. Then when you tap it, it runs
an asynchronous getCurrentLocation and updates some stuff. Then the next
time you tap another list element, the variables bound in the callback of
the getCurrentLocation Function only refer to the first time it was
called. Why doesn't this work??
app = { events: [{text: "foo", time: new Date()}, {text: "bar", time: new
Date()}] };
$(document).ready(refreshEvents);
function refreshEvents() {
for (var index in app.events) {
insertEventHTML(app.events[index]);
}
}
function insertEventHTML(event) {
var text = event.text;
var time = event.time;
var new_element = $('<li class="event_element"></li>');
var new_checkin_element = $('<div class="check_in_button"></div>');
new_checkin_element.bind('tap', function(e) {
check_in(e);
fade($(this), 1.0);
});
new_element.append(new_checkin_element);
var text_element = $('<div class="text_element">' + text + '</div>');
new_element.append(text_element);
var time_element = $('<div class="time_element">' + time + '</div>');
new_element.append(time_element);
$('#your_events').append(new_element);
}
function check_in(e) {
$(e.target).siblings('.time_element').text('just now');
var time = new Date(); // time and event_index are
the trouble variables here
var event_index = getEventIndex(e); // the first time this
function runs, event_index is correct
// then each subsequent time,
it remains the same value as
the first
if (!app.settings.use_location) {
app.events[event_index].times.unshift({time: time, location: null});
} else {
AppMobi.geolocation.getCurrentPosition(onLocationFound,
errorFunction);
}
function onLocationFound(response) {
var lat = response.coords.latitude;
var lon = response.coords.longitude;
var last_time = app.events[event_index].times[0];
if (last_time != undefined && last_time.time == time) {
// event_index and time here will only ever refer to the first
time it was called. WHY???
add_checkin(response, event_index, time);
}else{
console.log('onLocationFound was called twice');
}
}
function errorFunction(error) {
$.ui.popup({title: 'geolocation error', message: 'Geolocation
error. Turn off location services in settings.'});
}
function add_checkin(response, event_index, time) {
// and then of course event_index and time are wrong here as well.
I don't get it.
app.events[event_index].times.unshift(
{
time: time,
location: {
latitude: response.coords.latitude,
longitude: response.coords.longitude
}
});
AppMobi.cache.setCookie('app', JSON.stringify(app), -1);
}
}
function getEventIndex(e) {
var target = $(e.target).parent();
var siblings = target.parent().children('li');
for (var i = 0; i < siblings.length; i++) {
if ($(target)[0].offsetTop == $(siblings[i])[0].offsetTop) {
return i;
}
}
}
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