Intents allow communication between components in Android. They can be explicit, naming a specific component, or implicit, specifying an action for Android to resolve. Intents can share data between components via extras. Components declare intent filters to specify the intents they can handle. Developers can define intents to reuse functionality from other apps or expose functionality to other apps. Intents are a core part of Android that enable reuse and interoperability.

1. Israel Ferrer
Android Lover since 2008
cofounder bubiloop
cofounder android.es
Barcelona GTUG Leader
Android Dev at Fever
Head Mobile Dept. at ASMWS
Computer Science at LaSalle

2. INTENTS
ARE AWESOME
really, trust me!
Israel Ferrer
14th March

3. WHAT ARE
INTENTS
?

4. intent |inˈtent| noun
intention or purpose:
with alarm she realized his
intent | a real intent to cut back
on social programs.
flickr: chinesetealover

5. OK... WHAT DOES THIS REALLY MEAN?

6. Open new Screens
Share with other apps
Open Camera to take a photo
Open file manager
Open the browser
Open QR Code Scanner
...

7. HOW INTENTS
WORK
?

8. Explicit Intent
Implicit Intent
theatricalintelligence

9. EXPLICIT INTENTS
• Explicit
Intent names the component which should be called
by the Android system, using the Java class as identifier.
• Used to open new activities in the same app.
final Intent intent=new Intent(this, LoginActivity.class);
startActivity(intent);

10. IMPLICIT INTENTS
• Implicitintent specifies the action to perform and optionally an
URI for the action.
• Implicit
Intent is managed by Android Intent resolution, which
maps the intent to a Service, Activity or Broadcasts Receiver
• Thisresolution is done by matching intent with intentFilters of
every app.
• Ifmore than one app can handle the action, the user will have
to choose.
final Intent intent=new Intent(Intent.ACTION_VIEW, "http://mylookout.com");

11. SHARE DATA
• Intents can contain aditional data by using putExtra() method
• intent.putExtra(EXTRA_CONVERSATION, conversation);
• the
receiving component can obtain this data by getExtras()
method
Bundle extras = getIntent().getExtras();
String conversation = extras.getString(EXTRA_CONVERSATION);
if (conversation != null) {
// Do something with the data
}

12. INTENT FILTERS
• AnIntentFilter specifies the types of Intent that an activity,
service, or broadcast receiver can respond to. IntentFilters are
declared in the Android Manifest.
• There are 3 pieces of information used for this resolution:
• Action
• Type: mymeType or scheme.
• Category: need to support DEFAULT to be found by
startActivity.

13. INTENT FILTERS
Intent
final Intent intent=new Intent(Intent.ACTION_VIEW, "http://mylookout.com");
IntentFilter
<activity android:name=".BrowserActivitiy" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="http"/>
</intent-filter>
</activity>

14. TO SUM UP
• Explicit: choose the component to call.
• Implicit: isa general intent with action and optionally URI.
The Intent resolution call the component that can handle it.
• Intents can share data between components and apps.

15. HOW TO
USE
INTENTS
?

16. • Reuse code and functionality from 3rd party apps
• ACTION_SEND
• ACTION_VIEW
• geo:lat,lon to open map
• http://host to open browser
• tel:number to open dialer

17. • Define a set of intents to handle web addresses.
• Example: Twitter
• Define IntentFilter to handle twitter urls
<activity android:name=".UrlHandleActivity" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:host="www.twitter.com" android:scheme="http" />
</intent-filter>
</activity>

18. • Check the URL path to fire target Activity
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Uri uri = getIntent().getData();
if (null == uri) {
// Shouldn't happen. Handle errors.
finish();
return;
}
String path = uri.getPath();
for (Pair<String, Class> pair : DISPATCH_MAP) {
if (path.matches(pair.mFirst)) {
Intent intent = new Intent(this, pair.mSecond);
intent.setData(uri);
startActivity(intent);
finish();
return;
}
}
finish();
}
private static final List<Pair<String, Class>> DISPATCH_MAP
= new LinkedList<Pair<String, Class>>();
static {
DISPATCH_MAP.add(new Pair<String, Class>("(.*)/status$",
TweetActivity.class));
DISPATCH_MAP.add(new Pair<String, Class>("/another/path",
ProfileActivity.class));
}

19. • Exposeintents to 3rd party apps. Example: Lookout public
backup intent.

20. CONCLUSIONS

21. A core component of Android.
A way to reuse functionality between apps.
The glue between activities.
The mashup concept into a mobile platform
Intents are Awesome for users & developers

22. QUESTIONS?