Question

I have been searching everywhere on the web and trying everything that I can think of so far to no avail. Here is my problem:
In my program I have a class called Scale, Scale has several properties. The user can add scales to a tableView by clicking a button called addScale. When addScale is pressed, I add it to a OrderedMutableSet. I use the set to store the scales and prevent duplicate scales. I had to override the isEqual method and the Hash method to fool the computer into thinking that two Scales with the same properties are exactly the same. This works fine. But when I open the app and have had previously some scales in the tableView, I have archiving implemented so these scales reappear, as expected. This time, when addScale is pressed, I get an exception:

    -[__NSOrderedSetI addObject:]: unrecognized selector sent to instance 0x746dbf0
    2011-08-29 13:20:49.095 MusicLog[678:f203]
    *** Terminating app due to uncaught exception 'NSInvalidArgumentException', 
    reason: '-[__NSOrderedSetI addObject:]: unrecognized selector sent to instance 0x746dbf0'

Here is the code for my isEqual method and my Hash method:
(tonic, mode, rhythm, octaves, and tempo are all ints)

- (NSUInteger)hash
{
    NSUInteger prime = 31;
    NSUInteger result = 1;
    result = prime * result + tonic;
    result = prime * result + mode;
    result = prime * result + rhythm;
    result = prime * result + octaves;
    result = prime * result + tempo;
    NSLog(@"%u", result);
    NSLog(@"%u", NSUIntegerMax);

    return result;
}


- (BOOL)isEqual:(Scale *)object
{
    if ((tonic == [object tonic])
        && (mode == [object mode])
        && (rhythm == [object rhythm])
        && (octaves == [object octaves])
        && (tempo == [object tempo]))
        return YES;
    else 
        return NO;
}

Here is the code for my addScale method:

- (IBAction)addScale:(id)sender
{
    Scale *chosenScale = [[Scale alloc] init];
    [chosenScale setTonic:[myPicker selectedRowInComponent:0]];
    [chosenScale setMode:[myPicker selectedRowInComponent:1]];
    [chosenScale setRhythm:[myPicker selectedRowInComponent:2]];
    [chosenScale setOctaves:[octavesSegmentedControl selectedSegmentIndex] + 1];
    [chosenScale setTempo: (int) [tempoStepper value]];
    [[ScaleStore defaultStore] addScale:chosenScale];
}

the addScale method of the ScaleStore just calls addObject from a NSOrderedMutableSet which is where all the scales are stored.

Any help you can give is greatly appreciated.

Thank you,

K

Answer 1

When you unarchive, the objects are restored to an immutable version (NSMutableSet becomes NSSet, NSMutableArray becomes an NSArray, etc.)

Just create a new NSOrderedMutableSet with objects from the restored set.