NSDictionary setValue:

Question

OK, this is driving me nuts -- please tell me I'm not losing my mind!

I declare:

NSMutableDictionary* generalSettingsDict;

im my .h

I init:

generalSettingsDict = [[NSMutableDictionary alloc] initWithCapacity:5];

in a viewWillAppear

I set:

[generalSettingsDict setValue:[NSNumber numberWithBool:control.on]
                       forkey:[NSNumber numberWithInt:control.tag]];

in a method:

-(void)settingChanged:(UISwitch*)control forEvent:(UIEvent *)event

And I get "NSMutableDictionary may not respond to setValue:forkey:" and the app crashes when it is run.

Please help :(

You also have a typo: forKey:, not forkey:. And for the record, `NSMutableDictionary` does support `setValue:forKey:`, but I still prefer to use `setObject:forKey:`. — Alex, Jul 28 '09 at 18:10

score 26 · Accepted Answer · answered Jul 28 '09 at 18:09

26

A) forkey: should be forKey:. Capitalization is important.

B) setValue:forKey: is a KVC method. It may work as you expect here, but the proper method to use for NSMutableDictionary is setObject:forKey:

answered Jul 28 '09 at 18:09

kperryua

You'll also find, even after correcting the method name, that KVC keys must be strings. You have to use the native NSMutableDictionary `setObject:forKey:` method to use arbitrary objects as keys. – Chuck Jul 28 '09 at 18:24

score 6 · Answer 2 · answered Jul 28 '09 at 18:09

6

You want setObject:forKey:. setValue:forKey: is part of the key-value coding protocol. NSMutableDictionary provides setObject:forKey:.

answered Jul 28 '09 at 18:09

Alex

2 Answers2