Mobile 2.0 Open Ideas WorkShop: Building Social Media Enabled Apps on Android

Workshop:

Building Social Media Enabled
Android Apps
Mobile 2.0 Open Ideas
Alberto Alonso Ruibal
alberto.ruibal@mobialia.com
T: @mobialia @albertoruibal

Who am I
Telecommunication Engineer
System Manager
J2EE Developer
Android Developer @ Mobialia
Chess apps: Mobialia Chess, Internet Chess Club
Gas Stations Spain
...
My blog: http://www.alonsoruibal.com
My company: http://www.mobialia.com

Other Android learning resources
I developed the WikiPlaces app as an example for
LabAndroid Málaga. This app contain samples of how to
do many common things on Android:
● Dashboard
● Creating preferences screens and retrieving preferences
● Google Maps API, including overlays, Location API
● Using external JSON sevices
● Lists and adapters
● Launching external apps with Intents
● AdMob integration
http://www.mobialia.com/labandroid

Why integrate social media?

● Get data from social media
● App visibility on social networks

● Sharing app data (like high scores)

● Easy login for your users on your app

● Get additional user data

Social media integration demo app

All the examples in this slides are
in a sample open-source application:

http://www.mobialia.com/mobile20/

The share button
● Very easy to implement
● We can launch an “ACTION_SEND” intent to be
received by the social media applications

public void onShareChoose(View v) {
String shareText = ((EditText) findViewById(R.id.EditText)
).getText().toString();
Intent intent = new Intent(android.content.Intent.ACTION_SEND);
intent.setType("text/plain");
intent.putExtra(android.content.Intent.EXTRA_TEXT, shareText);
startActivity(Intent.createChooser(intent,
getResources().getText(R.string.share_choose)));
}

Intents
Are an Android system that we can use
to launch activities of the same or
different applications

An activity launches an intent
The intent can include “extra” data
Other activity receives the intent

This shows the activity chooser

Choosing the component
We can launch an specific activity
(the official twitter app in this sample):

PackageManager packageManager = context.getPackageManager();

List<ResolveInfo> activityList = packageManager.queryIntentActivities(intent, 0);

for (ResolveInfo act : activityList) {

if (act.activityInfo.name.indexOf("com.twitter.") == 0) { // Check it if starts by...

ComponentName name = new ComponentName(act.activityInfo.applicationInfo.packageName,
act.activityInfo.name);

intent.setComponent(name);

startActivity(intent);

...

Twitter Integration

● In this sample we will show our timeline
● Twitter uses OAUTH authentication
● Twitter API response is JSON
● Multiple options, I prefer libsignpost
http://code.google.com/p/oauth-signpost/

Adding signpost
Library provided in three flavours:
● java.net.HttpUrlConnection
● Apache Commons HTTP (we will use this)
● Jetty HTTP Client
To use it, download:
● signpost-core-1.2.1.1.jar
● signpost-commonshttp4-1.2.1.1.jar
And add them to your build path on Eclipse

Getting a Twitter API key (I)
Register your app at https://dev.twitter.com/apps

Getting a Twitter API key (II)
Once registered, you can get your app's consumer
key and secret and insert them in the code:

OAuthConsumer oauthConsumer = new CommonsHttpOAuthConsumer(
// the consumer key of this app (replace this with yours)
"RFbRzd0BzYGZjrDd02ec5g" ,
// the consumer secret of this app (replace this with yours)
"wo9lKhzwpEfdXS2Z3dO2W092W9pMoJGrc5kUsBdA");

Authenticating user
Now we redirect our users to the authentication URL,
specifying a callback URL:
public static String CALLBACK_URL = "socialmediademo://twitter";
//...
String authUrl = oauthProvider.retrieveRequestToken(oauthConsumer,
CALLBACK_URL);
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(authUrl));
// save token
accessToken = oauthConsumer.getToken();
tokenSecret = oauthConsumer.getTokenSecret();
intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP |
Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_FROM_BACKGROUND |
Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);

Twitter Authentication

Twitter page is opened on
the system web browser

This sample is read-only
(no post or follow)

Intercepting Callback URL
We intercept the callback “socialmediademo://twitter” URL
modifying the AndroidManifest.xml:
<activity
android:name =".TwitterProviderActivity"
android:label ="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.VIEW"></action>
<category android:name="android.intent.category.DEFAULT"></category>
<category android:name="android.intent.category.BROWSABLE"></category>
<data android:scheme="socialmediademo" android:host="twitter"></data>
</intent-filter>
</activity>

Verifying user login
Then, on the receiving activity
(TwitterProviderActivity):

Uri uri = this.getIntent().getData();
String verifier = uri.getQueryParameter(OAuth.OAUTH_VERIFIER);
oauthConsumer.setTokenWithSecret(accessToken, tokenSecret);
oauthProvider.retrieveAccessToken(oauthConsumer, verifier);
// save new token
accessToken = oauthConsumer.getToken();
tokenSecret = oauthConsumer.getTokenSecret();

Getting updates from timeline
Now we can query Twitter REST API methods:

String url =
"http://api.twitter.com/1/statuses/home_timeline.json?count=100";
HttpGet request = new HttpGet(url);
HttpClient httpClient = new DefaultHttpClient();
// sign the request
oauthConsumer.setTokenWithSecret(accessToken, tokenSecret);
oauthConsumer.sign(request);
HttpResponse response = httpClient.execute(request);

Parsing the JSON responses
Android API integrates a JSON parser!

JSONArray array = new JSONArray(response);
for (int i = 0; i < array.length(); i++) {
JSONObject user = object.getJSONObject("user");
Update update = new Update();
update.setMessage(Html.fromHtml(object.getString("text")
).toString());
update.setUserId(user.getString("screen_name"));
update.setUserName(user.getString("name"));
// ...

Finally we show the updates

On the source code you
can also find:
● List adapter for updates
● Image Cache

LinkedIn Integration
● Very similar to Twitter, we can also use
libsignpost
● XML/JSON API
● A small difference: we need to specify to
signpost that LinkedIn uses OAUTH version
1.0a:
oauthProvider.setOAuth10a(true);

Getting a LinkedIn API key
https://www.linkedin.com/secure/developer

LinkedIn Authentication

Works like Twitter, opening it
on the system's browser.

We also have a callback URL

Calling the LinkedIn API
By default in XML, we must send the parameter
“&format=json”

String response =
httpRequest("http://api.linkedin.com/v1/people/~/network/updates?
count=100&format=json");
if (response != null) {
JSONObject object = new JSONObject(response);
//...

LinkedIn result

Shows updates from your
LinkedIn contacts

Using social media for logging-in
No need to create a user account
I recommend Facebook:
● More users

● More user data

We can get additional user information!
● Gender

● Birthday

● ...

Facebook Integration

● Uses OAUTH 2.0, signpost does not support it
● Download Facebook SDK from Github:
https://github.com/facebook/facebook-android-sdk/
● We need to add the Facebook SDK as a
separate project and add a project dependency
● Use the new Graph API methods!

Getting a Facebook API key (I)
https://www.facebook.com/developers/

Getting a Facebook API key (II)
Here we have the Application ID
To obtain the key hash: keytool -exportcert -alias androiddebugkey
-keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl
base64

Preparing the Facebook Object
And launching the facebook authentication...

final int ACTIVITY_CODE = 777;
final String appId = "219172308103195";
final String[] PERMISSIONS = new String[] { "user_birthday" };

Facebook fb = new Facebook(appId);
fb.authorize(this, PERMISSIONS, ACTIVITY_CODE, this);
// (Callback not detailed)

Login with Facebook

Opens a Facebook
Activity requesting
authentication data

Getting user data from Facebook
When we are authenticated, we can do requests,
“/me” gets user information

String res = fb.request("/me");
JSONObject object = new JSONObject(res);
Log.d(TAG, object.getString("id"));
Log.d(TAG, object.getString("name"));
Log.d(TAG, object.getString("gender"));
Log.d(TAG, object.getString("birthday"));

Improving ads with user data
● With AdMob we can specify user gender and
birthday:
AdRequest adRequest = new AdRequest();
adRequest.setGender(Gender.FEMALE);
adRequest.setBirthday("19790129");
AdView adView = (AdView) this.findViewById(R.id.adView)
adView.loadAd(adRequest);

Facebook result
The demo app shows the
user data
The Ad shown is requested
with the user data
We can use the user data on
may parts of our application

More ideas
● You can also use a WebView to
integrate social media features
● “Follow” button integrating twitter API

● “Like” button: needs to create a

facebook object associated
● “Foursquare” API integration

Questions...

Thanks for your attention!

Alberto Alonso Ruibal
alberto.ruibal@mobialia.com
http://www.mobialia.com
T: @mobialia @albertoruibal

Mobile 2.0 Open Ideas WorkShop: Building Social Media Enabled Apps on Android

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