Back closes whatever is on the front; home brings the home screen to the front. Everything else falls out from that.
On Tue, Dec 16, 2008 at 12:47 AM, jarkman <jark...@gmail.com> wrote: > > Justin - thanks for the explanation. > > I'm not making any allegation of impropriety on the part of the > system, just trying to understand what the orthodox behaviour ought to > be for a 'vanilla' app. > > I had completely missed the distinction between leaving via 'back' and > leaving via 'home', which may account for some of my confusion. I'm > not sure our users will get that distinction either, but fortunately > our state is pretty simple so they can't get too bemused. > > So, just to check, is the plan that leaving via 'home' seems to the > user like sending the app to the background, to be restored later, > whereas leaving via 'back' is closing the app, so it next starts in a > virgin state ? > > > Richard > > > On Dec 16, 12:18 am, "Justin (Google Employee)" <j...@google.com> > wrote: > > Richard, > > > > If you save something into the bundle and hit 'home' (button with a > > house on it), the system will always return a non-null Bundle to you. > > If you don't save anything to the Bundle, I'm not sure what the system > > will do. > > > > If you hit the 'back' button (button with the arrow), the system will > > not call onSaveInstanceState and therefore give a null Bundle to > > onCreate. > > > > The other thing that comes to mind is that if you're trying to tweak > > launch modes, the system may be launching a new instance of your > > Activity, which it would launch with a null Bundle. If this is the > > case, hitting the 'back' button should eventually reveal another > > instance of your same Activity. > > > > Its also worth noting that onPause is *not* always followed by onCreate > > (), it may be followed by onResume or onStop. onStop may then be > > followed by onRestart, followed by onStart. > > > > If the system is improperly discarding state, this would be the first > > time I've seen it, but its not impossible. > > > > Cheers, > > Justin > > Android Team @ Google > > > > On Dec 15, 9:32 am, jarkman <jark...@gmail.com> wrote: > > > > > I'm a bit confused by the saved instance state mechanism. > > > > > If I breakpoint in onCreate, run the app, hit the Home button, then > > > relaunch the app, I typically see a null Bundle passed in to > > > onCreate. > > > > > But, if I (for example) rotate the emulator, I see a non-null Bundle > > > in onCreate, and the app has the right state after the rotation. > > > > > What causes the null in the first example ? It looks as though the > > > system has thrown away the saved instance state on our behalf. > > > > > Thanks, > > > > > Richard > > > > > > > -- 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. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
