Streets of Boston, please forgive my ignorance. If I use AsyncTask within a service to retrieve data once, can I destroy the AsyncTask after? Or would I have to destroy the entire Service?
Additionally, if I want to poll, say, every 5 minutes, wouldn't having AsyncTask in the service be a good idea, instead of tying up the Service, which might be needed for other operations? Finally, what do you mean when you said to use a regular Thread that calls 'post' on the owning Activity? On Jan 21, 10:37 pm, Streets Of Boston <[email protected]> wrote: > A Service, like an Activity, has a main thread with a message-loop. > You can create an AsyncTask in the onXXXXX() callbacks of Services, > just like in an Activity. The onPostExecute can do your handling of > the results, as you described. > > However, AsyncTask is more geared towards the one-time executing of a > background process. E.g. retrieve some data from the internet now, or > create/process a bitmap. It is not really meant to stay in the > background forever in a loop polling for some data to come in. When > you have something like 'while (true)' or 'while (!mStopped)' or > something like it, you should not use a AsyncTask. Use a regular > Thread instead that calls 'post' on the owning Activity that will > consume the results generated by the thread. > > On Jan 21, 6:22 pm, Flapjack <[email protected]> wrote: > > > According to my research, which includes reputable sources (Mark > > Murphy et al), the most preferred way of polling a remote source and > > presenting said data to the user is by creating a service and using > > AsyncTask within that service to do the polling. I have done that. > > > But, when I read the docs (http://developer.android.com/reference/ > > android/os/AsyncTask.html), there seem to be several "Threading Rules" > > that conflict with this way of doing things: "The task instance must > > be created on the UI thread." and "execute(Params...) must be invoked > > on the UI thread." As stated, I have created the task instance on the > > Service thread (not the UI thread). Am I missing something? > > > Also, when the AsyncTask finished, I sent out a Broadcast on > > onPostExecute, which is then picked up by the Activity, telling it to > > retrieve the final value again from the service (since I couldn't > > obviously update the UI from the service). I couldn't figure out any > > other way to return the result of the AsyncTask. Is this the correct > > practice? > > > Java is not my native language so please bear with my ignorance. > > Thanks! > > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
