Unexpected behavior of IntentService
- by kknight
I used IntentService in my code instead of Service because IntentService creates a thread for me in onHandleIntent(Intent intent), so I don't have to create a Thead myself in the code of my service.
I expected that two intents to the same IntentSerivce will execute in parallel because a thread is generated in IntentService for each invent. But my code turned out that the two intents executed in sequential way.
This is my IntentService code:
public class UpdateService extends IntentService {
public static final String TAG = "HelloTestIntentService";
public UpdateService() {
super("News UpdateService");
}
protected void onHandleIntent(Intent intent) {
String userAction = intent
.getStringExtra("userAction");
Log.v(TAG, "" + new Date() + ", In onHandleIntent for userAction = " + userAction + ", thread id = " + Thread.currentThread().getId());
if ("1".equals(userAction)) {
try {
Thread.sleep(20 * 1000);
} catch (InterruptedException e) {
Log.e(TAG, "error", e);
}
Log.v(TAG, "" + new Date() + ", This thread is waked up.");
}
}
}
And the code call the service is below:
public class HelloTest extends Activity {
//@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent selectIntent = new Intent(this, UpdateService.class);
selectIntent.putExtra("userAction",
"1");
this.startService(selectIntent);
selectIntent = new Intent(this, UpdateService.class);
selectIntent.putExtra("userAction",
"2");
this.startService(selectIntent);
}
}
I saw this log message in the log:
V/HelloTestIntentService( 848): Wed May 05 14:59:37 PDT 2010, In onHandleIntent for userAction = 1, thread id = 8
D/dalvikvm( 609): GC freed 941 objects / 55672 bytes in 99ms
V/HelloTestIntentService( 848): Wed May 05 15:00:00 PDT 2010, This thread is waked up.
V/HelloTestIntentService( 848): Wed May 05 15:00:00 PDT 2010, In onHandleIntent for userAction = 2, thread id = 8
I/ActivityManager( 568): Stopping service: com.example.android/.UpdateService
The log shows that the second intent waited the first intent to finish and they are in the same thread.
It there anything I misunderstood of IntentService. To make two service intents execute in parallel, do I have to replace IntentService with service and start a thread myself in the service code?
Thanks.
