tableView: titleForHeaderInSection: causing crash

Question

For some reason, the tableView: titleForHeaderInSection: method is causing the application to crash without giving any details as to why. I know it is this method because when I comment it out, the table loads, just without headers obviously.

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *monthArray = [NSArray arrayWithObjects:@"January", @"February", @"March", @"April", @"May", @"June", @"July", @"August", @"September", @"October", @"November", @"December", nil];

 NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
 NSCalendarUnit unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit;
 NSDate *date = [NSDate date];
 NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

 NSInteger year = [dateComponents year];
 NSInteger month = [dateComponents month];

 currentYear = [NSString stringWithFormat:@"%d", year];
 nextYear = [NSString stringWithFormat:@"%d", year+1]; 

 [dateComponents setMonth:month];

 currentYearMonths = [[NSMutableArray alloc] init];
 nextYearsMonths = [[NSMutableArray alloc] init];

 for(uint i=month-1; i<=11; i++){
  [currentYearMonths addObject:[monthArray objectAtIndex:i]];
 }
 for(uint i=0; i<month-1; i++){
  [nextYearsMonths addObject:[monthArray objectAtIndex:i]];
 }

 [calendar release];
}


- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
 NSString *sectionHeader = nil;

 if(section == 0) {
  sectionHeader = currentYear;
 }
 if(section == 1) {
  sectionHeader = nextYear;
 }  
 return sectionHeader; 
}

Answer 1

You're missing a few retain statements look below where you set currentYear and nextYear to see what should fix it.

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *monthArray = [NSArray arrayWithObjects:@"January", @"February", @"March", @"April", @"May", @"June", @"July", @"August", @"September", @"October", @"November", @"December", nil];

    NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSCalendarUnit unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit;
    NSDate *date = [NSDate date];
    NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

    NSInteger year = [dateComponents year];
    NSInteger month = [dateComponents month];

    currentYear = [[NSString stringWithFormat:@"%d", year] retain];
    nextYear = [[NSString stringWithFormat:@"%d", year+1] retain]; 

    [dateComponents setMonth:month];

    currentYearMonths = [[NSMutableArray alloc] init];
    nextYearsMonths = [[NSMutableArray alloc] init];

    for(uint i=month-1; i<=11; i++){
        [currentYearMonths addObject:[monthArray objectAtIndex:i]];
    }

    for(uint i=0; i<month-1; i++){
        [nextYearsMonths addObject:[monthArray objectAtIndex:i]];
    }

    [calendar release];
}