Removing objects from array in NSUserDefaults

Question

When setting NSUserDefaults , I was initially using this code to set the defaults...

 NSMutableArray *array = [NSMutableArray arrayWithObjects: @"string1", @"string2", @"string3", nil];
 [[NSUserDefaults standardUserDefaults] setObject:array forKey: @"preset1"];
 [[NSUserDefaults standardUserDefaults] synchronize];

I've learned that I should be using this instead:

NSMutableArray *array = [NSMutableArray arrayWithObjects: @"string1", @"string2", @"string3", nil];
NSDictionary *appDefaults = [NSDictionary dictionaryWithObject:array forKey:@"preset1"];
[[NSUserDefaults standardUserDefaults] registerDefaults:appDefaults];

Now I'm having an issue manipulating the objects later on in array . Here is the code I use to add/remove strings from array . It worked fine when I was initially setting the defaults manually in my first example. Now, the objects will not remove from the array. I did notice when printing the array in LLDB debugger that array is now being stored as a NSCFArray when it was just an NSArray before.

NSMutableArray *array = [[NSMutableArray alloc] init];
[array addObjectsFromArray:[[NSUserDefaults standardUserDefaults] objectForKey:@"preset1"]];

NSArray *stringsToRemove = @[@"string1", @"string2" ]; 

for (NSUInteger i = 0; i < stringsToRemove.count; i++) {
    [array removeObjectIdenticalTo:[stringsToRemove objectAtIndex:i]];
}

[[NSUserDefaults standardUserDefaults] setObject:array forKey: @"preset1"];
[[NSUserDefaults standardUserDefaults] synchronize];  

Answer 1

This code works for me with your setup, after initializing the defaults the second way you described:

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

NSMutableArray *array = [[NSMutableArray alloc] initWithArray: [defaults objectForKey:@"preset1"]];

NSArray *stringsToRemove = [NSArray arrayWithObjects:@"string1", @"string2", nil];

for (NSString *aString in stringsToRemove) {
     [array removeObjectIdenticalTo:aString];
}

[defaults setObject:array forKey: @"preset1"];
[defaults synchronize];