Slug: HTML5 for Mobile Web Applications, ISBN number, 23! kyrnin hour23-code.doc

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1 Slug: HTML5 for Mobile Web Applications, ISBN number, 23! kyrnin hour23-code.doc Hour 23 Code to detect support for GeoLocation, simply detect if the browser has that object: function supports_geolocation() { return!!navigator.geolocation; To use the getcurrentposition() method, you call it in a function with a callback method for success and failure: function getlocation() { navigator.geolocation.getcurrentposition(mapit, locationerror); Then the success method (mapit() above) uses the position object in some fashion: function mapit(position) { var lat = position.coords.latitude; var lon = position.coords.longitude; alert("you are at "+ lat +" latitude, and "+ lon +" longitude."); While the error method (locationerror() above) provides feedback on any error received: function locationerror(error) { switch(error) { case 1: case 2: alert("location services denied"); alert("could not contact location services network or satellites");

2 case 3: alert("location services timed out"); default: alert("location could not be determined."); to use the watchposition() method, you call it with success and error callbacks: var watch; function getlocation() { watch = navigator.geolocation.watchposition(mapit, locationerror); if you want to stop watching that user s location change, you would call clearwatch() with that number: function clearlocation() { navigator.geolocation.clearwatch(watch); To enable high accuracy, you write: getcurrentposition(mapit, locationerror, {enablehighaccuracy: true); To set a timeout of a minute and a half (90,000 milliseconds), write: getcurrentposition(mapit, locationerror, {timeout: 90000); To set the maximum age to two minutes (120,000 milliseconds), write: getcurrentposition(mapit, locationerror, {maximumage: 90000); You can also put all these options together into a variable, and deliver them that way: var positionoptions = { enablehighaccuracy: true,

3 timeout: 90000, maximumage: ; getcurrentposition(mapit, locationerror, positionoptions); To use geo.js, you download geo.js and install both Google Gears and geo.js at the bottom of your document: <script src=" <script src="geo.js"></script> Then you check for location services, from any source with the geo_position_js.init() method. This returns true if the browser can provide location services, either through the GeoLocation API or Gears. if(geo_position_js.init()) { geo_position_js.getcurrentposition(success_callback,error_callback); In the success callback, you can then grab the position coordinates just like you would in the HTML5 API: function success_callback(position) { var lat = position.coords.latitude; var lon = position.coords.longitude; alert('you are at:\nlat: '+lat+' Long: '+lon); you can get the location of the server for this book s companion website by typing: 2. Create a standard HTML5 page with jquery <!DOCTYPE HTML> <html> <head> <meta charset="utf-8"> <title>untitled Document</title> <meta name="viewport" content="width=device-width"/>

4 </head> <body> </body> </html> <script src="jquery.min.js"></script> 3. In the <head> link to the Bing Maps API <script charset="utf-8" type="text/javascript" src=" 4. For the HTML, create an area to indicate support of GeoLocation <section> <h2>where Are You Now?</h2> <p id="supports">your browser does not support GeoLocation</p> </section> 5. You should also include a section to display the map, the map options and the trigger to get the map <section id="getmapinfo"> <h3>map Options</h3> <p>zoom level: Orbit (1) <input id="zoomlvl" value="11" type="range" min="1" max="20"> Your yard (20) <p><button id="getgeo">get My Location</button></p> <div id="map"></div> </section> 6. Then in a <script> element at the bottom of the page, write the function to check for GeoLocation and add that to the document ready function $(document).ready(function(e) { ); if (supportsgeolocation()) { else { $("#supports").html("your browser supports GeoLocation. "); $("#supports").html("your browser does not support GeoLocation. "); $("#getmapinfo").hide(); // hide the button and map section function supportsgeolocation() { return!!navigator.geolocation;

5 7. Then add a click function to the button to start the mapping process $("#getgeo").click(function(e) { ); getlocation(); return false; 8. Add the getlocation() function function getlocation() { navigator.geolocation.getcurrentposition(mapit, locationerror); 9. Add the error callback function locationerror() to provide information on what error occurred function locationerror(error) { switch(error) { case 1: case 2: case 3: default: alert("location services denied"); alert("could not contact location services network or satellites"); alert("location services timed out"); alert("location could not be determined."); $("#getmapinfo").hide(); $("#supports").append(" There was an problem mapping your location, please try again later."); 10. Then write the mapit() function. This is where you use the Bing Maps API key or other mapping API of your choice. function mapit(position) { var lat = position.coords.latitude; var lon = position.coords.longitude; var zoom = parseint($("#zoomlvl").val()); var map, mapoptions, center, pin, pinoptions; // show a map from Bing

6 mapoptions = { credentials: 'YOUR BING MAPS KEY', center: new Microsoft.Maps.Location(lat, lon), zoom: zoom ; map = new Microsoft.Maps.Map(document.getElementById('map'), mapoptions); $("#map").after('<h3 class="after">you are Here</h3>'); Be sure to change the credentials to your Bing Maps API key. 11. I also like to add a custom pin to the map, so that it s easy to see where it s centered, add these lines after the map = new Microsoft.Maps... line. center = map.getcenter(); pinoptions = { ; icon: "/images/house.png", width: 16, height: 16, draggable: true pin = new Microsoft.Maps.Pushpin(center, pinoptions); map.entities.push(pin); For example: <img src=" [ic:ccc]center= , &size=400,400&zoom=12"> 5. This property is one of the position options that can be set on the getcurrentposition() and watchposition() methods. You set it to true when you need the position data to be as accurate as possible, such as for turn-by-turn driving directions. To use it, you write: getcurrentposition(success_callback, error_callback, {enablehighaccuracy: true); Or: watchposition(success_callback, error_callback, {enablehighaccuracy: true);

Geolocation in HTML5 and Android. Kiet Nguyen

Geolocation in HTML5 and Android Kiet Nguyen Agenda Introduction to Geolocation Geolocation in Android Geolocation in HTML5 Conclusion Introduction to Geolocation To get user's location Common methods: