Save NSMutable dictionary data in plist file _ integers as key - iphone

Question

I'm currently trying to save a NSMutabledictionary keys and objects in a plist file. My keys are integers, so I'm using NSNumber to put them into the writeToFile function.
Even with that change, I cant find any of my saved data in the plist find. I suppose there is a problem with the NSNumber pointer because when I use a string it works.
do you have an idea of what is missing in my code?
NSMutableDictionary *dictionnaireNoms = [[NSMutableDictionary alloc] initWithCapacity:40];
NSNumber *nombre = [[NSNumber alloc] initWithInteger:dictionnaireNoms.count];
NSString *nomCommerce = text.text;
[dictionnaireNoms setObject:nomCommerce forKey:nombre];
//2. Sauvegarde du nom dans un fichier
[saveDicoCommerce enregisterNom:dictionnaireNoms];
- (void)enregisterNom:(NSMutableDictionary*)nom
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSLog(#"%#", documentsDirectory);
NSString *pathNom = [documentsDirectory stringByAppendingPathComponent:#"NomsDeCommerces.plist"];
if (!documentsDirectory) {
NSLog(#"Documents directory not found!");
return;
}
[nom writeToFile:pathNom atomically:YES];
if(![[NSFileManager defaultManager] fileExistsAtPath:pathNom])
{
NSLog(#"file not found");
return;
}
}

Answer 1

NSDictionary can only write itself directly if it only contains string keys. It confirms this you try to write using
[[NSPropertyListSerialization dataWithPropertyList:nom format:NSPropertyListBinaryFormat_v1_0 options:0 error:nil] writeToFile:pathNom atomically:NO];`
The output is:
Property list invalid for format: 200 (property list dictionaries may only have keys which are CFStrings, not 'CFNumber')
However, you can store NSDictionary objects containing NSNumber keys if you serialize it using NSCoding. Replace this:
[nom writeToFile:pathNom atomically:YES];
with:
[NSKeyedArchiver archiveRootObject:nom toFile:pathNom];
To read the file created, use:
NSDictionary *nom2 = [NSKeyedUnarchiver unarchiveObjectWithFile:pathNom];
For more information about archives, see the Archives and Serializations Programming Guide.

Answer 2

Why do u want to allocate NSNumber? Try this [your_dictionary setValue:[NSNumber numberWithInt:your_int]];