1. Reactive Android Development
CS T & CS T
Summer 2016

2. Running jobs in the background
Intent Service
Can not interact directly with the UI
Results must be sent to the activity for it to handle
Work requests run sequentially
If one request blocks, all others must wait until it is finished
An operation running on an intent service can not be interrupted
If the result is no longer desired, it must be ignored after it arrives.

3. Running jobs in the background
IntentService class
public class RSSPullService extends IntentService {
@Override
protected void onHandleIntent(Intent workIntent) {
// Gets data from the incoming Intent
String dataString = workIntent.getDataString();
...
// Do work here, based on the contents of dataString }

4. Running jobs in the background
Manifest entry
<service
android:name=".RSSPullService"
android:exported="false"/>

5. Sending a work request
As with most operations, this begins with creating an intent object
Intent = new Intent(getActivity(),
RSSPullService.class);
intent.setData(Uri.parse(dataUrl));
Then you call getActivity().startService(intent)

6. Sending results Results must be sent to a broadcast service
But there is a LocalBroadcastManager that can be used to limit recipients to your own application.

7. Receiving Results Your app must define a broadcast receiver
And register with the LocalBroadcastManager
For receiving local messages only
You can apply an IntentFilter to restrict the type of broadcast messages that you will actually receive.

8. Response to Broadcast
The tutorials emphasize that you should not start an activity in response to a broadcast event
However, you can send a Notification to the user.

9. Networked Communication
Network Service Discovery
Advertise your app's service
Find services on your network

10. Network Service Discovery
Registering your service
NsdServiceInfo class
Info.setService("Name");
Info.setServiceType("_http._tcp.");
Info.setPort(<port number>);

11. P2P Over Wifi
The router is optional
Longer range than bluetooth

12. Network Connections
<uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

13. Threading for a responsive app
Network activities should not be performed on the main activity thread.
Unpredictable delays
AsyncTask
doInBackgroundMethod
OnPostExectute
Can make UI changes!