Generally a CursorLoader monitors for changes to the underlying database, and delivers a new Cursor to you when the data changes. So you could certainly be putting new objects in mPeople if the contacts change.
On Sun, Nov 6, 2011 at 11:53 AM, Jay <[email protected]> wrote: > I really don't do much else with mPeople, though I can think of two > other things it might be. As I said, mPeople does supply a > ListAdapter. Is it possible that is doing some behind the scenes > cloning? Perhaps more likely, mPeople is populated by a CursorLoader > attached to the Contacts content provider. I am not 100% clear on the > semantics of loaders (I've been working from the docs and from > examples), so maybe something I'm not accounting for is triggering the > loader to asynchronously refresh mPeople. To be safe I guess I should > throw in a class to loader.stopLoading() once mPeople has been > populated. > > > Jay > > On Nov 6, 1:57 pm, Dianne Hackborn <[email protected]> wrote: > > Well as far as I know ArrayList won't just do this behind your back. I > > would assume there is something else your app is doing that isn't shown > > here. Are you sure you never change what is in mPeople that could cause > a > > new instance of an object to be created? > > > > > > > > > > > > > > > > > > > > On Sat, Nov 5, 2011 at 10:16 PM, Jay <[email protected]> wrote: > > > Thank you for the reply. Is there some other mechanism by which the > > > objects in my array might be replaced with objects with the same type > > > and contents but different identities (i.e. don't compare as equal > > > using the default implementation)? Because that seems to be what is > > > happening (intermittantly). > > > > > Thanks, > > > Jay > > > > > On Nov 6, 12:00 am, Dianne Hackborn <[email protected]> wrote: > > > > None of the methods you are using will copy an object. Generally you > > > must > > > > explicitly call clone() to do this. > > > > > > On Sat, Nov 5, 2011 at 6:25 AM, Jay <[email protected]> > wrote: > > > > > I assume this is an Android question, though it may just betray my > > > > > ignorance of Java memory management. > > > > > > > I have an activity designed to randomly pick a person from a list, > and > > > > > to not repeat anyone until everyone has been chosen. The core > logic of > > > > > the pick method looks like this: > > > > > > > ArrayList<Person> peopleCopy = new > ArrayList<Person>(mPeople); > > > > > peopleCopy.removeAll(mRecent); > > > > > Person person = > peopleCopy.get(mRNG.nextInt(peopleCopy.size())); > > > > > mRecent.add(person); > > > > > // Display chosen person in UI > > > > > > > Both mPeople and mRecent are referenced by adapters that feed into > > > > > ListViews. > > > > > > > The bug I was finding is that the same person was being chosen more > > > > > than once in a cycle, despite the code above. I had a hell of a > time > > > > > tracking it down; I couldn't duplicate it on the emulator or on the > > > > > actual device when connected to the debugger. I finally managed to > > > > > "catch" the bug in progrss on the device and plug it in to the > > > > > debugger. Based on the object id fields, it appears that the > problem > > > > > is that the Person objects referenced my mRecent were different > from > > > > > the ones in peopleCopy, which is why the removeAll method was not > > > > > subtracting them correctly. I implemented appropriate equals() and > > > > > hashcode() methods on Person and that seems to have fixed the > problem. > > > > > > > My question is where/when/why were the Persons in mRecent and/or > > > > > mPeople being replaced with clones? It wasn't happening all the > time; > > > > > based on observations with the debugger, it appears that usually > the > > > > > lists referenced the same objects as I expected them to. Does the > > > > > framework sometimes clone objects referenced by adapters or does > Java > > > > > or am I misreading this whole situation? > > > > > > > Thanks, > > > > > Jay > > > > > > > -- > > > > > 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 > > > > > > -- > > > > 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 > > > > -- > > 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 > -- 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
