Question

I am using a date formatter string in order to get the current date as follows:

NSDateFormatter* dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
dateFormatter.dateFormat = @"EEEE / dd-MM-yyyy";
timeLabel.text = [dateFormatter stringFromDate:[NSDate date]];

Now i need to decrement the date by 1 on a button press, If the the date today is Friday/05-08-2011, then on button press it should display Thursday/04-08-2011.
How can i achieve this ?

Answer 1

Code like this (in addition to above answer)

- dateByAddingTimeInterval: available in 4.0 and later, you can use - addTimeInterval for lower version (deprecated in 4.0 or later).

-(IBAction)decrementDate
{
    NSString *dateForDecrement=timeLabel.text;
    NSDateFormatter* dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
    dateFormatter.dateFormat = @"EEEE / dd-MM-yyyy";
    NSDate *dateObjectForDecrement=[dateFormatter dateFromString:dateForDecrement];

    NSDate *dateAfterDecrement=[dateObjectForDecrement addTimeInterval:-(24*60*60)];
     timeLabel.text =  [dateFormatter stringFromDate:dateAfterDecrement];
}