> On 7 Apr 2015, at 12:01 pm, Daryle Walker <[email protected]> wrote: > > I have an object like: > > @interface MyClass : NSObject > @property (readonly) NSArray * myDatumList; > @property NSArray * myDataList; > @end > > The second member is meant to be an actual data member, an array of mutable > dictionaries. The first member isn’t supposed to have a backing store; > accessing a member of the first array references the corresponding member of > the second, then access a dictionary attribute with a custom key. > > I have a custom array count and array element read methods for the first > member. > > The program does nothing now. I checked with my limited debugging skills that > the second member has one element, but the first member is looped though as > if it has no elements. I see that BOTH “_myDatumList” and “_myDataList” > internal members exist, with the former set as NIL. I’ve heard that we used > to need to use the “@synthesize” command to create internal members, then a > later version of the Objective-C compiler did it automatically. Now I have > the reverse problem; the first member gets a backing store automatically, but > I do NOT want that; I always want to use the custom array accessor methods to > simulate “myDatumList” with pieces of “myDataList.” > > So, how can I turn off auto-@synthesize? Using “@dynamic” doesn’t work; it > causes a crash due to a missing [MyClass myDatumList] method. I also saw a > random page saying that “self.myDatumList” causes this, but “myDatumList” > wouldn’t (like the “self.” gives the unwanted backing store have priority > over the array accessor methods). Is that accurate?
You need to write your own getter method for myDatumList, and write the code in there to do what you want it to do. Since it's a readonly property, the compiler will be satisfied that you've done everything necessary to implement the property and won't give it any backing store at all. As a general comment, I personally find the automatic creation of backing store by default leads to bugs and confusion - how it was originally with the requirement to either use @synthesise and/or write your own methods was cleaner and less bug-prone, even if it did add a tiny bit of extra work. C'est la vie... --Graham _______________________________________________ Cocoa-dev mailing list ([email protected]) 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 [email protected]
