const static NSDictionary

Question

Level 1

32 points

const static NSDictionary

I have to use this long dictionary of constants in my app. I decided to save on the CPU time and place it in its own class method as a static const variable, but for some reason it produces this error:
{quote}
error: initializer element is not constant
{quote}


+(const NSDictionary*)getNamesDictionary
{
 const static NSDictionary* dic = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:
 @"value1",
 //Very long list of values
 nil] forKeys:[NSArray arrayWithObjects:
 @"key1",
 //Very long list of keys
 nil]];
 return dic;
}

Can someone suggest how to remedy this?

MacBook Pro 17", 2.66 GHz i7, 4GB 1067 DDR3 RAM, OS X 10.6.4 /// iPhone 4, 32GB, iOS 4

Posted on Jan 25, 2011 1:30 PM

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Answer 1

etresoft

Level 9

56,692 points

Jan 25, 2011 1:45 PM in response to Den B.

Get rid of const. That is more of a C++ thing.

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Answer 2

Den B. Author

Level 1

32 points

Jan 25, 2011 1:58 PM in response to etresoft

I still get the same error if I go with:


 static NSDictionary* dic = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:
 @"value1",
 //Very long list of values
 nil] forKeys:[NSArray arrayWithObjects:
 @"key1",
 //Very long list of keys
 nil]];

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Answer 3

RayNewbie

Level 5

6,810 points

Jan 25, 2011 2:41 PM in response to Den B.

Hi Den -

static vars can't be initialized with code. Maybe you want something like this:

+ (NSDictionary*)getNamesDictionary {
 static NSDictionary* dic = nil;
 
 if (dic == nil)
 dic = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:
 @"value1",
 //Very long list of values
 nil] forKeys:[NSArray arrayWithObjects:
 @"key1",
 //Very long list of keys
 nil]];
 return dic;
}

- Ray

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Answer 4

Den B. Author

Level 1

32 points

Jan 25, 2011 3:03 PM in response to RayNewbie

Thanks, Ray. But I get the EXC BADACCESS if I try the following with your code:


const NSDictionary* dicNames = [SharedClass getNamesDictionary];
[dicNames count]; //Exception here!

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Answer 5

RayNewbie

Level 5

6,810 points

Jan 25, 2011 3:30 PM in response to Den B.

Ooops, sorry Den. I just pasted your initialization code without thinking 😟 We don't want to use the convenience method to create the dictionary without retaining it:


static NSDictionary* dic = nil;
+ (NSDictionary*)getNamesDictionary {
 
 if (dic == nil)
 dic = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:
 @"value1",
 //Very long list of values
 nil] forKeys:[NSArray arrayWithObjects:
 @"key1",
 //Very long list of keys
 nil]];
 return dic;
}

As shown, you might also consider moving the static declaration out of the method so dic can be released in the dealloc method.

- Ray

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Answer 6

Den B. Author

Level 1

32 points

Jan 25, 2011 3:43 PM in response to RayNewbie

Thanks, you did it this time.

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