Question

I have some table cells displaying different time. I want the time to be updated (just like countdown).

I tried to call [my_table_name reloadData] every second but the method does not invoke logics in cellForRowAtIndexPath. How can I loop through the cells of UITableView to update its contents?

UPDATE: the time displayed is in form of 10 days 11:12:49 ( each cell has an expiry date, when the table is updated, the expiry date subtracts current time & calculate the time remaining , which is displayed on cell )

UPDATE 2: There are 2 methods to reload data. One is calling from server, one is calling the function only.

- (void)reloadLocal {
  [my_table_name reloadData];
}

and the online method is:

- (void)reloadFromServer {
  [self parseXML:@"URL here"];
}
- (void)parseXML:(NSString *)URL {
  // read the XML & update a NSArray containing the data
}

the reloadLocal method is called like this (in viewDidLoad )

current = [[NSDate date] retain];
[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(reloadLocal) userInfo:nil repeats:YES];

for the cellForRowAtIndexPath method, here is the pseudo codes (too long to post all lines):

static NSString *identifier = @"CustomCell";
CustomCell *cell = (CustomCell *)[tableView dequeueReusableCellWithIdentifier:identifier];

NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:identifier owner:nil options:nil];
    for (id currendObj in topLevelObjects) {
        if ([currendObj isKindOfClass:[UITableViewCell class]]) {
            cell = (CustomCell *)currendObj;
            break;
        }
    }
// then insert data to related UIOutlet elements.
NSDate *validUntil = [[NSDate alloc] initWithTimeInterval:diff sinceDate:current];

NSCalendar *sysCalendar = [NSCalendar currentCalendar];
unsigned int unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit | NSDayCalendarUnit | NSSecondCalendarUnit;

NSDateComponents *conversionInfo = [sysCalendar components:unitFlags fromDate:current toDate:validUntil options:0];

cell.lbl_day.text = [NSString stringWithFormat:@"%d", [conversionInfo day]];
cell.lbl_minute.text = [NSString stringWithFormat:@"%d", [conversionInfo minute]];
cell.lbl_second.text = [NSString stringWithFormat:@"%d", [conversionInfo second]];
cell.lbl_hour.text = [NSString stringWithFormat:@"%d", [conversionInfo hour]];

note that current is an instance of current time, in data type NSDate.

Answer 1

End up I discovered if I update the date variable current in reloadLocal, the time displaying will automatically be updated.