An Activity's onDestroy is called all the time (but not every time :)). It is true that you can't *rely *on it being called, though.
E.g. the onDestroy is always called when you click the 'back' key or do some other action (code-execution) that causes the Acitivity's 'finish()' method to be called. On Monday, January 14, 2013 11:55:10 AM UTC-5, Kristopher Micinski wrote: > > While you say that Activities only die when the process is about to be > destroyed (or usually die), I have heard that this is not the case. > This is mostly hearsay from developers and people I work with saying > that memory leaks because of this were really a problem, but I'd have > to look into it with some examples (of layouts that really use memory, > I'm thinking galleries and nested views, etc..) before making any > definite calls. > > Kris > > On Mon, Jan 14, 2013 at 9:37 AM, G. Blake Meike > <[email protected]<javascript:>> > wrote: > > After spending considerable time looking at this issue, I strongly > suggest > > that you look into an Intent Service, for any long running task. Using > > AsyncTasks is just fraught. > > > > First of all, onDestroy is only called best effort. If you care about > > getting it done, you can't do it in onDestroy. Further, as kris points > out, > > onDestroy is, often, called just as your *process* is about to be > destroyed. > > Worrying about allocation of memory in your process, just as it is > > destroyed, is pretty pointless. > > > > There are two issues you need to consider: making your program correct > > according to Java ("If mutable state is referenced from more than one > > thread, all references must take place holding a single lock" - B. > Goetz, > > paraphrased). You also have to be sure that the lifecycles of unmanaged > > objects (e.g. AsyncTasks) don't interfere with the lifecycles of managed > > objects (Activities). > > > > Nulling out pointers and AsyncTasks that survive screen reorientation > > (despite the fact that I proposed it myself, at one point) are just > Voodoo. > > > > G. Blake Meike > > Marakana > > > > Programming Android 2ed is now in stores: > > http://bit.ly/programmingandroid > > > > > > On Monday, January 14, 2013 1:10:52 AM UTC-8, Greenhand wrote: > >> > >> Thank you. > >> Another related question, in section "5. Implement a more intelligent > >> AsyncTask dealing with screen orientation" of > >> > http://blog.doityourselfandroid.com/2010/11/14/handling-progress-dialogs-and-screen-orientation-changes/, > > > >> it has private AsyncTaskComplex activity in ListFresher as a member > >> variable. Shouldn't it be null out because it is not a static Activity > >> references? > >> > >> > >> Kristopher Micinski於 2013年1月14日星期一UTC+8下午4時24分53秒寫道： > >>> > >>> Basically, as long as you aren't hanging static Activity references > >>> you should be fine. The main activity will be thrown away upon its > >>> destruction, at which point the Activity will be thrown away: along > >>> with its contents. Of course, if you're holding onto Views elsewhere > >>> that's bad (i.e., don't hold static refs). > >>> > >>> kris > >>> > >>> On Mon, Jan 14, 2013 at 1:42 AM, Greenhand <[email protected]> > wrote: > >>> > I read > >>> > > >>> > > http://android-developers.blogspot.tw/2009/01/avoiding-memory-leaks.html > >>> > about avoiding memory leaks. > >>> > I would like to know whether I should null out all member variables, > >>> > such as > >>> > TextView and Button in onDestroy()? Or, unregistering listener, > >>> > unbinding > >>> > service and etc.in onDestroy() are enough to prevent memory leak? > >>> > > >>> > -- > >>> > > -- > > 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]<javascript:> > > To unsubscribe from this group, send email to > > [email protected] <javascript:> > > 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 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
