That makes sense, but going back to the X Y Z example, I have lists in X and Y with items that open in Z, so I go back and forth a lot between Z and either X or Y. I want the user experience to be seamless, and according to the performance guide http://developer.android.com/guide/practices/design/performance.html launching an activity (even an empty one) is one of the heaviest operations you can do. Is there a way to reuse an activity that has been opened once?
On May 8, 1:02 pm, Dianne Hackborn <[email protected]> wrote: > Indeed, you can't, because singleInstance (and singleTask) means that the > activity is managed independently of the previous activity that is launching > it, so there can be know guarantees about when or in what order the result > will be returned. > > Don't use singleInstance. > > Why do you want singleInstance? You probably don't. You have to realize > that by doing this you are splitting your app into separate tasks, which > will mess up the user's interaction with it as they go in and out of your > app. > > As far as you using singleInstance as a way to hide the fact that your > activity is too slow to start... really, I would suggest fixing that > instead. :) If your view hierarchy takes too long to inflate, it is > probably way overly complicated -- either with a lot of complicated layout > managers that can be simplified, or a lot of things that are normally hidden > that you should only inflate when needed (see Romain's articles on this for > help). > > If there are other things you do that are slow, you can look at keeping > those objects in singletons in your process so they only need to be created > the first time the activity is started, and can be re-used thereafter as > long as your process is aound. (But first optimize optimize optimize to try > to make them not slow! If your activity is so slow to start that you are > doing this, you are making it only somewhat better by reducing the times the > user need to wait... there will still be many times when they still need to > wait.) > > > > On Fri, May 8, 2009 at 5:54 AM, kingtut <[email protected]> wrote: > > > I basically have three activities X, Y, Z and I want only one instance > > of each but I want control over the navigation and I can't do that by > > putting all three activities in one task because of the stack > > structure. > > > Here is a scenario, from X I launch Y given a certain "id" which > > correspondence to specific data in the DB, Y inflates and populates > > it's views, then I go back to X and launch Y again with a different > > "id" in the intent, I don't want the overhead of launching the > > activity and inflating the views again, anyone know how to do this? > > > I tried using singleInstance, but the problem is that I can't send the > > result code back to an activity in a different task. > > -- > Dianne Hackborn > Android framework engineer > [email protected] > > 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 [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 -~----------~----~----~----~------~----~------~--~---
