Save class object use NSUserDefaults + Mental

SaveClassObject

+ (id)objectForKey:(NSString *)key
{
    if ([key length] == 0) {
        return nil;
    }
    
    NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:key];
    if (!data) {
        return nil;
    }
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

+ (void)setObject:(id)value forKey:(NSString *)key
{
    if ([key length] == 0) {
        return;
    }
    
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:value];
    if (!data) {
        return;
    }
    
    [[NSUserDefaults standardUserDefaults] setObject:data forKey:key];
    [[NSUserDefaults standardUserDefaults] synchronize];
}