> 2) make a __weak reference to self, and only use that inside the block, your > controller won't be retained.
That's another alarming problem that I have become aware of in context of my question. It turns out that if you use blocks instead of delegates inaccurately, you can end up creating a strong reference (e.g. by mentioning self in the block) and a circular reference even without being aware of it. I am now seriously thinking that blocks can be evil for replacing delegates (which by convention are always assign properties, i.e. weak references). Am I right? On Fri, Apr 19, 2013 at 10:10 AM, Charles Srstka <cocoa...@charlessoft.com> wrote: > On Apr 19, 2013, at 1:01 AM, Oleg Krupnov <oleg.krup...@gmail.com> wrote: > >> I recently encountered an alarming problem that I have never been >> aware of, and I'd like to ask about the best practice to handle it. >> >> Is it true that any object (let's call it Controller) that owns an >> NSTimer, scheduled to fire a method (let's call it -timerDidFire) of >> the same Controller, creates a circular reference and causes the >> Controller to never be released and the timer never stop triggering? >> >> It looks like scheduling the timer causes the run loop to retain a >> reference to the object that implements -timerDidFire, in this case >> it's the Controller. Is this true? Then this is a circular reference, >> right? >> >> In this case, if [_timer invalidate]; is called only in Controller's >> dealloc, then the timer never stops firing? >> >> Which is the best way to prevent this problem? Currently I'm thinking >> about some kind of -[controller disconnect]; method that I need to >> call before [controller release]; in controller's parent object, but >> that seems a bit unwieldy solution. >> >> Any other ideas/considerations? Thanks! > > What I'd probably do would be to use a GCD timer instead of an NSTimer. That > way, you can pass the timer a block instead of a reference to the controller, > and as long as you either 1) don't reference self within the block or 2) make > a __weak reference to self, and only use that inside the block, your > controller won't be retained. > > Charles > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
