In addition to Treking's answer; Never rely on the order in which (you think that) activities are started to initialize or modify static/global data.
E.g. User goes through your app, starting from the homescreen, going from Activity A then to Activity B then to C. This could be order in which the activities are created: A --> B --> C Now your user presses the Home key and does something else for a while and the OS decides to kill your app, because it is in the background. When the user comes back to your app, this may happen (it depends how your activities were launched): First Activity C is shown, since that was the last one that the user saw. When the user now hits the back-button a few times, this could be the order in which the activities are created: C --> B --> A. Total different order. If your global/static data relies on the activitie's creation order, you may run into subtle or not-so-subtle problems. On Monday, February 25, 2013 11:34:43 AM UTC-5, TreKing wrote: > > > On Mon, Feb 25, 2013 at 3:52 AM, user123 <[email protected] <javascript:> > > wrote: > >> And I'm wondering, if there's any case where I can get a null pointer? >> Because e.g. the system kills the app while it's in the background, and >> tries to restart it in the last screen - since the variable is only >> initialized in the launcher screen, it will not be initialized? Does this >> case exist? >> > > To answer your question, yes that exact case does exist, so you don't want > to initialize your data in the launcher screen. > > > ------------------------------------------------------------------------------------------------- > TreKing <http://sites.google.com/site/rezmobileapps/treking> - Chicago > transit tracking app for Android-powered devices > -- -- 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 --- You received this message because you are subscribed to the Google Groups "Android Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
