objective c - UITableView: hide header from empty section

Question

i have a UITableView, that displays expenses from a current month (see screenshot):

My problem is with the header for empty sections. is there any way to hide them? The data is loaded from coredata.

this is the code that generates the header title:

TitleForHeader

-(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{
if ([tableView.dataSource tableView:tableView numberOfRowsInSection:section] == 0) {
    return nil;
} else {

NSDate *today = [NSDate date ];
int todayInt = [dataHandler getDayNumber:today].intValue;

NSDate *date = [NSDate dateWithTimeIntervalSinceNow:(-(todayInt-section-1)*60*60*24)];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:[[NSLocale preferredLanguages] objectAtIndex:0]]];    
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *formattedDateString = [dateFormatter stringFromDate:date];
    return formattedDateString;}

}

ViewForHeader

-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section{
if ([tableView.dataSource tableView:tableView numberOfRowsInSection:section] == 0) {
    return nil;
} else {

    UIView *headerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 312, 30)];
    UILabel *title = [[UILabel alloc]initWithFrame:CGRectMake(4, 9, 312, 20)];
    UIView *top = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 312, 5)];
    UIView *bottom = [[UIView alloc]initWithFrame:CGRectMake(0, 5, 312, 1)];

    [top setBackgroundColor:[UIColor lightGrayColor]];
    [bottom setBackgroundColor:[UIColor lightGrayColor]];

    [title setText:[expenseTable.dataSource tableView:tableView titleForHeaderInSection:section]];
    [title setTextColor:[UIColor darkGrayColor]];
    UIFont *fontName = [UIFont fontWithName:@"Cochin-Bold" size:15.0];
    [title setFont:fontName];


    [headerView addSubview:title];
    [headerView addSubview:top];
    [headerView addSubview:bottom];

    return headerView;

}

}

heightForHeader

- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {

NSLog(@"Height: %d",[tableView.dataSource tableView:tableView numberOfRowsInSection:section] == 0);
if ([tableView.dataSource tableView:tableView numberOfRowsInSection:section == 0]) {
    return 0;
} else {
    return 30;
}
}

numberOfRowsInSection

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {

int rows = 0;
for (Expense* exp in [dataHandler allMonthExpenses]) {
    if ([exp day].intValue == section) {
        rows++;
    }
}

return rows;
}

sebastian

Answer 1

You have to set tableView:heightForHeaderInSection: to 0 for the appropriate sections. This is something which changed fairly recently and got me in a couple places. From UITableViewDelegate it says...

Prior to iOS 5.0, table views would automatically resize the heights of headers to 0 for sections where tableView:viewForHeaderInSection: returned a nil view. In iOS 5.0 and later, you must return the actual height for each section header in this method.

So you'll have to do something like

- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
    if ([tableView.dataSource tableView:tableView numberOfRowsInSection:section] == 0) {
        return 0;
    } else {
        // whatever height you'd want for a real section header
    }
}