So you really don't want to *return*, hence the setResult() isn't appropriate in your case. You just want to communicate something back to the parent activity, is that right? In this case you want to use a broadcast receiver.
Cheers On Wed, Mar 4, 2009 at 3:28 PM, Chronos <g358279012044...@gmail.com> wrote: > >> You should set the result when your child activity is about to exit - >> for example I set the result from my child activity when a button is >> clicked and just before exiting it, e.g.: >> >> // in a button click handler >> setResult(...); >> finish(); > > This is the way they do it in the samples, but it makes not much sense > - I don't want to have an "exit" or "save" button; users should be > able to hit "back" (listening for "back" is my current workaround, but > it will probably fail under certain circumstances). > >> The documentation for Activity mentions that "When an activity exits, >> it can call setResult(int) to return data back to its parent." > > Yes - it says so. But it doesn't say WHEN - this is my problem; I > don't know when to setResult efficiently: onPause() doesn't work, > onSaveInstanceState() doesn't work; listening for "back" ain't > failproof; listening for data changes is ineffective. *sigh* > >> When you're getting a NPE what does you stacktrace look like? > > Nevermind the NPE - it comes from RESULT_CANCELLED and Intent.getExtras > () returning null. > >> btw, you shouldn't assume that the parent activity will outlive the >> child one - that is, the fact that your parent activity has spawned >> another one for result doesn't mean it won't be destroyed should the >> system need to destroy it because it's not in the foreground. > > Yes, I don't. > > On Mar 4, 1:58 pm, Stoyan Damov <stoyan.da...@gmail.com> wrote: >> On Wed, Mar 4, 2009 at 2:41 PM, Chronos <g358279012044...@gmail.com> wrote: >> >> > Thanks for the idea - but this is not my problem: the result sent is >> > the result I set in the onCreate method (a default result); if I fail >> > to do this, I will get a java.lang.NullPointerException, which >> > underlines my point - setResult() in onPause() is too late; my >> > activity is not cancelled either - I always get an Activity.RESULT_OK. >> >> You should set the result when your child activity is about to exit - >> for example I set the result from my child activity when a button is >> clicked and just before exiting it, e.g.: >> >> // in a button click handler >> setResult(...); >> finish(); >> >> The documentation for Activity mentions that "When an activity exits, >> it can call setResult(int) to return data back to its parent." >> >> When you're getting a NPE what does you stacktrace look like? >> >> >> >> > Do you think, onPause() is the correct point to setResult() ? It seems >> > to me, that the result has already been transmitted in some >> > communication queue at this point - all calls to setResult() are in >> > vain. >> >> btw, you shouldn't assume that the parent activity will outlive the >> child one - that is, the fact that your parent activity has spawned >> another one for result doesn't mean it won't be destroyed should the >> system need to destroy it because it's not in the foreground. >> >> >> >> > On Mar 4, 12:39 pm, Stoyan Damov <stoyan.da...@gmail.com> wrote: >> >> Actually read >> >> carefullyhttp://developer.android.com/reference/android/app/Activity.html#star...) >> >> >> On Wed, Mar 4, 2009 at 1:31 PM, Stoyan Damov <stoyan.da...@gmail.com> >> >> wrote: >> >> > Re: >> >> >> > - setResult() in client.onPause() is called TOO LATE; the result has >> >> > already been transmitted to the parent (although the method >> >> > client.onPause() seems to be called in time). >> >> >> > If the result has been already set, this means that the result value >> >> > is CANCELLED immediately after your child activity started. >> >> > Read carefully about the launchMode property - >> >> >http://developer.android.com/guide/topics/manifest/activity-element.h... >> >> >> > Cheers >> >> >> > On Wed, Mar 4, 2009 at 12:59 PM,Chronos<g358279012044...@gmail.com> >> >> > wrote: >> >> >> >> Hello there ;) >> >> >> >> I have some - maybe simple - problem; unfortunately I cannot find a >> >> >> solution: >> >> >> >> I have two activities which communicate via: startActivityForResult(), >> >> >> setResult(), onActivityResult. I will call the first activity "parent" >> >> >> and the second one "client", although this may not be technically >> >> >> correct; so the order of calls must be: >> >> >> >> parent.startActivityForResult() >> >> >> client.setResult() >> >> >> parent.onActivityResult() >> >> >> >> Now, where should I call setResult in the client activity ? >> >> >> >> I have already tried various possibilities which have all failed: >> >> >> >> - setResult() in client.onPause() is called TOO LATE; the result has >> >> >> already been transmitted to the parent (although the method >> >> >> client.onPause() seems to be called in time). >> >> >> - client.onSaveInstanceState() is not guaranteed to be called at all >> >> >> (and the documentation hints at the same timing problem). >> >> >> - The only TECHNICALLY POSSIBLE solution seems to implement a change- >> >> >> listener for any screen element and set the result there. This may >> >> >> work in theory, but is NOT VIABLE in practice: (1) it is strenuous and >> >> >> error-prone for activities with many elements; (2) it gets even more >> >> >> complicated, when side-effects kick in (change one field in dependency >> >> >> to another); (3) it is really slow, since one must write ALL contents >> >> >> any time, a SINGLE element changes (and the generic Intent >> >> >> communication is already slow by design). >> >> >> >> To me, it would seem most natural to overload the onPause() method and >> >> >> setResult() there - once and for all. There MUST be some easier way >> >> >> than implementing zounds of listeners ... >> >> >> >> Am I overlooking something ? Another listener I haven't stumbled over >> >> >> yet ? Please prove me wrong ;) > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. 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