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Display Facebook Friend position with Nokia Maps API for Qt

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==Source Code==
 
==Source Code==
 
The full source code of the example is available here: [[File: FacebookFriends_NokiaMap.zip]]
 
The full source code of the example is available here: [[File: FacebookFriends_NokiaMap.zip]]
 
  
 
==Related Article==
 
==Related Article==

Revision as of 17:50, 31 January 2012

This article demonstrates how to display Facebook friends on Nokia Map using Nokia Map API for Qt.

Article Metadata
Code ExampleTested with
Devices(s): N9/ N950
Compatibility
Platform(s): Symbian^3 and later/MeeGo, Qt 4.7.3 and later
Symbian
Device(s): GPS
Platform Security
Signing Required: Self-Signed
Capabilities: NetworkServices
Article
Keywords: Facebook, Map
Created: somnathbanik (31 Jan 2014)
Last edited: somnathbanik (31 Jan 2012)

Contents

Introduction

The example combines gets information about Facebook friends and display the location of the friends on Nokia Map using pushpin. We create dynamic pushpins with friend’s image using Dynamic Object Management in QML. This article also talks about Facebook login and authentication using OAuth. To start with the application first create a Facebook app from here and get the Key and Secret for future use.

Implementation

We create two pages in MainPage.qml, one is for displaying Facebook friend list and the other is to display friends on Nokia Map. When we start the application we load the Facebook login dialog in the first screen, which calls the Facebook login URL.

https://www.facebook.com/dialog/oauth?client_id=<Your Key>&redirect_uri=https://www.facebook.com/connect/login_success.html

By default the application will ask for the authentication of basic information about the user in Facebook. As we use user location and other information we need to request for more permissions from the user, which can be done with the scope parameter. So our URL should look like below.

https://www.facebook.com/dialog/oauth?client_id=<Your Key>&redirect_uri=https://www.facebook.com/connect/login_success.html&scope=user_hometown,friends_hometown,user_location,friends_location,email,publish_stream,offline_access,read_stream,user_status,user_photos,friends_photos,friends_status,user_checkins,friends_checkins,user_events

The login page is an HTML page, so we display it on QML WebView.

WebView {
id: webView
anchors.fill: parent
preferredHeight: height
preferredWidth: Math.max(parent.width,640)
url: "https://www.facebook.com/dialog/oauth?client_id=<Your Key>&redirect_uri=https://www.facebook.com/connect/login_success.html&scope=user_hometown,friends_hometown,user_location,friends_location,email,publish_stream,offline_access,read_stream,user_status,user_photos,friends_photos,friends_status,user_checkins,friends_checkins,user_events";//&display=touch";
onLoadFinished: {
loginDialog.finished( webView.url );
}
onLoadFailed: {
loginDialog.loadFailed();
}
}

Once the user is authenticated and authorizes the application, the browser will get an alpha-numeric number in the code parameter of its response. We parse the code for further use.

onFinished: {
if(url.indexOf("code=")>0) {
login.visible = false;
friendsList.visible= true;
var codeStart = url.indexOf("code=");
//CODE from facebook
var code = url.substring(codeStart + 5);
//get the access token
Facebook.getAccessToken(code);
console.log("Code: "+code);
}
}

getAccessToken() function pass the code as its parameter and calls the URL to get the access token.

function getAccessToken(code) {
//access token URL request
var url = "https://graph.facebook.com/oauth/access_token?client_id=<Your Key>&redirect_uri=https://www.facebook.com/connect/login_success.html&client_secret=<Your Secret>&code=" +code;
doWebRequest("GET", url, "", parseAccessToken);
}

And then we parse the access token from the response

//parse the access token
function parseAccessToken(response) {
accessToken = "access_token=" + parseParameter(response, "access_token");
console.log("parseAccessToken:"+accessToken);
//load friends on list
loadFriends();
}

loadFriends() gets friends information from Facebook and load the information on ListModel

function parseFriends(response) {
var data = eval("[" + response + "]")[0].data;
data = data.sort(sortByName);
friendsModel.clear();
for(var i in data) {
var user = data[i];
if(user.location!==undefined)
{
if(user.location.id !== "" || user.location.name !== null )
{
//save friends data in model
friendsModel.append({
"id": user.id,
"name": user.name,
// "profileImageUrl":"https://graph.facebook.com/" + user.id + "/picture",
"profileImageUrl":user.picture ,
"lid": (user.location!==undefined ? user.location.id : ""),
"lname": (user.location!==undefined ? user.location.name : ""),
});
}
}
}
//count number of content in the list model
friendsCount= friendsModel.count;
console.log("parseFriends : "+friendsCount);
}

Once the information are loaded in the ListModel, we display the list of Facebook friend List on the page

//display friends in list view
FriendsList {
id: friendsList
friendsModel: friendsModel
y: commonTools.height
height: parent.height - commonTools.height
}


On clicking the menu Friends on Map we call the function startcalculatingfrineds(), which first calculates the number of friends loaded in the model and then gets the location name for each friends.

function parseFriendsLocation()
{
//when friend list is more then zero
// get information about each friend from the model
if( i <friendsNumber)
{
fid = friendsModel.get(i).id;
fname = friendsModel.get(i).name;
fprofileImageUrl = friendsModel.get(i).profileImageUrl;
flid = (friendsModel.get(i).lid!==undefined ? friendsModel.get(i).lid : "" );
flname = (friendsModel.get(i).lname!==undefined ? friendsModel.get(i).lname :"");
i++;
if(flname !== "" || flid!== "" )
{
//pass friend location to get the latitude and longitude
feedModel.locationName = flname;
feedModel.reload();
}
else
{
//no user
console.log("no location for the user");
}
}
else
{
//count else
console.log("Stopped : "+friendsNumber);
}
}

The Facebook API we used here doesn’t provide the latitude and longitude information of friends in the friend list, so we will use Google API to get the latitude and longitude of each location individually.

XmlListModel {
id: feedModel
property string access_Token: ""
property string xmlData:"";
property string locationID:"";
property string locationName:""
// using Google API to get latitude and longitude of a location
source:"http://maps.googleapis.com/maps/api/geocode/xml?address="+locationName+"&sensor=false"
query:"/GeocodeResponse/result/geometry/location" //google query
namespaceDeclarations:""
//get latitude and longitude
//google
XmlRole { name: "lat"; query: "lat/string()" }
XmlRole { name: "lng"; query: "lng/string()" }
}

And then calls the addPushPin() function which first creates instances of PushPin.qml component dynamically using Dynamic Object Management in QML. Each instance is a MapImage with properties latitude,longitude,name and image. When the instances are ready we call the method addMapObject() to add the instance on the Map.

function addPushPin( latitude, longitude,name,friendImage)
{
count = map.markers.length
counter++
component = Qt.createComponent("PushPin.qml");
console.log(" Call "+component.status + " " + Component.Null);
//create pushpin object
object = component.createObject(container,
{ "latid": latitude, "longit": longitude,"name":name, "friendImage":friendImage}
);
if (object.status == Component.Ready)
{
console.log("Component ready");
map.addMapObject(object);
myArray = new Array()
for (var i = 0; i<count; i++){
myArray.push(map.markers[i])
}
myArray.push(object)
map.markers = myArray
}
else // when status is ready add the pushpin on the map
object.statusChanged.connect(addRemoteImages);
}
//add pushpn on the map
function addRemoteImages()
{
// console.log("addRemoteImages");
map.addMapObject(object);
myArray = new Array()
for (var i = 0; i<count; i++){
myArray.push(map.markers[i])
}
myArray.push(object)
map.markers = myArray
}

We also put the entire pushpins object into an Array, so that we can have a track of all the pushpin plotted on the Map. So when ever user switches from Facebook friends List View to Map View it will display the friends location on the Nokia Map.

Summary

This article shows the use of Nokia Map API along with Facebook API. It also talks about how to create a Map object dynamically using Dynamic Object Management in QML.

Source Code

The full source code of the example is available here: File:FacebookFriends NokiaMap.zip

Related Article


Note.pngNote: We will also come up with the same article on Windows Phone 7 . Please share your feedback to improvise the same.

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