If your callbacks are oneway, the easiest thing to do is put it all in a big
synchronized() block. Be aware though that if the callback is into the
local process, it will still be synchronous, so holding a lock while doing
this can be a problem.
Usually the safest thing is to have a handler that you post a message to,
which does the callbacks. Then you don't need any locking since the
broadcasts are serialized by the handler.
On Fri, Mar 13, 2009 at 10:55 AM, Streets Of Boston <flyingdutc...@gmail.com
> wrote:
>
> Ah, now i get it! :-)
>
> Indeed, sendProgressCallback can be called from multiple threads. And
> with your earlier explanation that the beginBroadcast does not do
> locking (only a brief internal lock), it may explain the problem. In
> other words, RemoteCallbackList is not thread-safe across multiple
> calls to it.
>
> I should put the broadcast code inside a 'synchronized(mCallbacks)
> { ... }' block or surround it with a ReentrantLock.
> Or create mCallbacks instances for each possible thread and have my
> listeners register with each of them.
>
> Thank you very much for your help.
> Have a great weekend!
>
> On Mar 13, 12:58 pm, Dianne Hackborn <hack...@android.com> wrote:
> > On Fri, Mar 13, 2009 at 7:27 AM, Streets Of Boston
> > <flyingdutc...@gmail.com>wrote:
> >
> > > Either way, it means that the number of items in the list accessed by
> > > getBroadcastItem is always equal to N.
> > > The problem remains: How can getBroadcastItem(int) return null?
> >
> > I'm not sure what you mean by "either way" -- if you are doing this from
> > multiple threads, your threads can clobber the list, which can lead to
> this
> > kind of problem.
> >
> > --
> > 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. All such questions should be posted on public
> > forums, where I and others can see and answer them.
> >
>
--
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. All such questions should be posted on public
forums, where I and others can see and answer them.
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