Thanks everyone. I knew it had to be something stupid....
I still feel that iterating over a dictionary means iterating over its
CONTENTS, not its KEYS --- but that's just my weird brain. Finally I found it
in the documentation as well.
Following Evadne Wu's advice it now works flawlessly.
On 02/06/2011, at 18:23, Evadne Wu wrote:
> Hello Motti,
>
> I believe -attributesByName returns a dictionary, where the keys are names
> (NSStrings) and the objects are NSAttributeDescription objects, so when you
> say `for (id something in aDictionary)` that `something` is going to be the
> key, not the object value [1], and you will just get the attribute
> description by using that key.
>
> This *might* work:
>
> - (NSMutableDictionary *)attributesAsDictionary {
> NSDictionary *attributesByName = self.entity.attributesByName
> NSMutableDictionary *returned = [NSMutableDictionary
> dictionaryWithCapacity:[attributesByName count]];
> for (NSString *aKey in [attributesByName allKeys]) {
> [returned setValue:[self valueForKey:aKey] forKey:aKey]; // nil allowed if
> my memory stands
> }
> return returned;
> }
>
> [1]: I believe you’ve assumed that for…in enumerates object values for
> NSDictionary objects?
>
> -ev
>
> On Jun 2, 2011, at 20:01, Motti Shneor wrote:
>
>> Hello everyone.
>>
>> We work with a CoreData model that is memory-based. However, at times I
>> would want to (partially) save an entity to the UserDefaults, as a
>> dictionary. For that, I wrote a little NSManagedObject extension (Category)
>> with the following method:
>>
>> @interface NSManagedObject (OURExtension)
>> @property (readonly) NSMutableDictionary *attributesAsDictionary;
>> @end
>> - (NSMutableDictionary *)attributesAsDictionary {
>> NSMutableDictionary *attributesDictionary = [NSMutableDictionary
>> dictionaryWithCapacity:[self.entity.attributesByName count]];
>> for (NSAttributeDescription* attribute in self.entity.attributesByName
>> ) {
>> NSString *attribName = [attribute name];
>> id attribValue = [self valueForKey:attribName];
>> if (attribName && attribValue)
>> [attributesDictionary setObject:attribValue
>> forKey:attribName];
>> }
>> return attributesDictionary;
>> }
>>
>> Running the method for a nice entity that I just Saved (validated) and
>> Fetched again (to be sure it's in the store) --- the method crashes horribly
>> on the NSString *attribName = [attribute name];
>>
>> If I step inside with the debugger, I see things I can't understand. I get
>> into the loop, and for the first attribute ---
>> 1. Debugger claims 'attribute's type is CFStringRef * instead of
>> NSAttributeDescription*
>> 2. Summary for attribute is "telephoneID" which is reasonable --- one of my
>> attributes is named like that.
>> 3. drilling down, the private "_name" iVar for the attribute is nil but
>> when I try to get it :
>> 4. NSString *attribName = [attribute name] crashes and debugger looses all
>> track of stack or anything.
>>
>> I looked for "valid" "isValid" or similar properties in
>> NSAttributeDescription and its ancestor NSPropertyDescription to no avail.
>> Nothing in the docs will tell me WHEN is it right to use the
>> NSAttributeDescription in the above manner.
>>
>> Ideas anyone?
Motti Shneor,
Senior Software Engineer and Team Leader, Spectrum Reflections LTD.
---
ceterum censeo microsoftiem delendam esse
---
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