Tracking changes in the current location in Symbian Web Runtime
This code snippet demonstrates how to track changes in the current location on Symbian Web Runtime, using the Location Service API.
Article Metadata
Tested with
Devices(s): Nokia 5800 XpressMusic
Compatibility
Platform(s): S60 5th Edition
Article
Keywords: device.getServiceObject(), Service.Location, Service.Location.Trace()
Created: User:Nokia Developer KB
(17 Nov 2008)
Last edited: hamishwillee
(05 Oct 2012)
Contents |
Source: widget.xhtml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<link rel="StyleSheet" href="style/general.css" type="text/css" />
<script type="text/javascript" src="script/script.js" />
<title>WRT Application</title>
</head>
<body>
<div id="bodyContent" class="bodyContent">
<div id="location">
<table id="locationData">
<tr id="latitude">
<td id="latitudeHeading">Lat.</td>
<td id="latitudeData"></td>
</tr>
<tr id="longitude">
<td id="longitudeHeading">Long.</td>
<td id="longitudeData"></td>
</tr>
</table>
</div>
<input type="button" value="Start tracking"
onclick="startTracking();" />
</div>
</body>
</html>
Source: script.js
var serviceObj = null;
var criteria = null;
window.onload = init;
// Initializes the widget
function init() {
// Obtain the Location service object
try {
serviceObj = device.getServiceObject("Service.Location", "ILocation");
} catch (ex) {
alert("Service object cannot be found.");
return;
}
// Initialize the criteria for the service object
criteria = new Object();
criteria.LocationInformationClass = "BasicLocationInformation";
}
// Starts the tracking
function startTracking() {
if (serviceObj == null) {
alert("Service object has not been initialized.");
return;
}
try {
// Define the callback function for tracking the location
var result = serviceObj.ILocation.Trace(criteria, locationDataReady);
} catch (ex) {
alert(ex);
}
}
// Called when Trace has got data
function locationDataReady(transId, eventCode, result) {
// On error situation, display the error message
if (eventCode == 4) {
alert("Error " + result.ErrorCode + ": " + result.ErrorMessage);
return;
}
var latitude = result.ReturnValue.Latitude;
displayData("latitudeData", latitude.toFixed(4) + " \u00B0");
var longitude = result.ReturnValue.Longitude;
displayData("longitudeData", longitude.toFixed(4) + " \u00B0");
}
// Displays the data in an HTML element
function displayData(elementId, data) {
var element = document.getElementById(elementId);
// Remove the first child node, if it's not null
if (element.firstChild != null) {
element.removeChild(element.firstChild);
}
element.appendChild(document.createTextNode(data));
}
Postconditions
The changes in current location are displayed.
