Overview

This code snippet demonstrates how to use the Location Service API of the Web Runtime to discover the location (latitude and longitude) of the device.

Source: script.js

var serviceObj = 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;
    }
 
    // We are interested in basic location information (longitude, latitude
    // and altitude) only, so let's define the criteria respectively
    var criteria = new Object();
    criteria.LocationInformationClass = "BasicLocationInformation";
 
    // Obtain the location information (synchronous)
    var result = serviceObj.ILocation.GetLocation(criteria);
    var latitude = result.ReturnValue.Latitude;
    var longitude = result.ReturnValue.Longitude;
 
    // Display the location
    alert("Lat. " + latitude + ", Long. " + longitude);
}

Note: GetLocation() is a synchronous function, so it may block your widget for a while.

Postconditions

The current location (latitude and longitude) of the device is displayed.

Supplementary material

• You can test the location obtaining features in action in a simple, executable application into which this code snippet has been patched. The application is available for download at: Media:WRTStub CS001161.zip
• You can examine all the changes that are required to implement the above mentioned features in an application. The changes are provided in unified diff and color-coded diff formats: Media:CS001161 Obtaining location information.diff.zip
• For general information on applying the patch, see Using Diffs.
• For unpatched stub applications, see Example stub.

See also

• Web Developer's Library: JavaScript Location Service API