[android-developers] sendBroadcast in IntentServicenot non-re-entrant?
I'm trying an experiment where an Activity makes a number of consecutive calls to an IntentService. Each call kicks off some background work that finishes in a few seconds. So there are multiple concurrent instances of the IntentService running. All the instances finish at around the same time and each one does a sendBroadcast to return a message to the Activity that it's finished. When this happens, about 30% of the broadcast intents never get back to the Activity's registered receiver. It looks as if there is some static state inside the IntentService class that is in conflict when there are multiple invocations running and they are all calling sendBroadcast at about the same time. In other words, sendBroadcast appears to be non-re-entrant. I'd like to package up this example for submission to b.android.com but before I do, I'd like to find out a few things from this forum: 1) Is this a known bug? 2) Is this expected behavior (ie not a bug)? 3) Has anyone seen anything like this or another case where the IntentService worked correctly when used in this way? -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] sendBroadcast in IntentServicenot non-re-entrant?
Bret, You saying that there are multiple concurrent instances of the IntentService running is not entirely accurate. If you actually defined multiple services in Java / the manifest, my apologies. If you only defined one service, then there is only one instance of the service, and any intents it receives are queued up to a thread-safe queue as soon as they are received. The worker thread (there is only one, AFAIK) then de-queues intents from this queue and processes them one by one. So no synchronization issues there. However, it's not out of the question that calling sendBroadcast, with it being a framework function, is only allowed from the UI thread, just like many other framework functions in Android. Since you are able to consistently reproduce this problem in your application, I think it wouldn't hurt to run a simple experiment. Change calls to sendBroadcast so they are made from the UI thread (e.g. obtain a Handler in your service's onCreate, then post a runnable containing the intent to be broadcast to the Handler). Also: for the case you described, you could use a lighter-weight notification mechanism, such as ResultReceiver or Message. -- Kostya 04.11.2010 20:54, Bret Foreman пишет: I'm trying an experiment where an Activity makes a number of consecutive calls to an IntentService. Each call kicks off some background work that finishes in a few seconds. So there are multiple concurrent instances of the IntentService running. All the instances finish at around the same time and each one does a sendBroadcast to return a message to the Activity that it's finished. When this happens, about 30% of the broadcast intents never get back to the Activity's registered receiver. It looks as if there is some static state inside the IntentService class that is in conflict when there are multiple invocations running and they are all calling sendBroadcast at about the same time. In other words, sendBroadcast appears to be non-re-entrant. I'd like to package up this example for submission to b.android.com but before I do, I'd like to find out a few things from this forum: 1) Is this a known bug? 2) Is this expected behavior (ie not a bug)? 3) Has anyone seen anything like this or another case where the IntentService worked correctly when used in this way? -- Kostya Vasilyev -- WiFi Manager + pretty widget -- http://kmansoft.wordpress.com -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] sendBroadcast in IntentServicenot non-re-entrant?
On Thu, Nov 4, 2010 at 1:00 PM, Kostya Vasilyev kmans...@gmail.com wrote: However, it's not out of the question that calling sendBroadcast, with it being a framework function, is only allowed from the UI thread, just like many other framework functions in Android. sendBroadcast can be called from any thread. There are no issues I know of with sendBroadcast dropping broadcasts, outside of the expected behavior I mentioned earlier. IntentService itself is extremely simple, and just enqueues each onStartCommand() to a handler. It is very unlikely things are being lost at that point. An interesting test case showing a problem would be something that derives directly from Service, showing that a call to startService() does not result in the given Intent appearing in Service.onStartCommand(). -- Dianne Hackborn Android framework engineer hack...@android.com Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
