Xcode Countdown Timer Doesn't Countdown (NSCalender) - xcode

Question

I am creating a simple IOS Application will a countdown timer. When I run the app in the simulator the countdown timer doesn't countdown. It simply stays at the current time.
Also any suggestions on making the numbers line up would be nice.
My .h file
// ViewController.h
// ******
//
// Created by ***** on 7/29/12.
// Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController {
NSDate *destinationDate;
IBOutlet UILabel *datelabel;
NSTimer *timer;
}
#end
My .m file
//
// ViewController.m
// ******
//
// Created by ******* on 7/29/12.
// Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//
#import "ViewController.h"
#implementation ViewController
-(void) updateLabel {
NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
int units = NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDateComponents *components = [calender components:units fromDate:[NSDate date] toDate:destinationDate options:0];
[datelabel setText:[NSString stringWithFormat:#"%d%c %d%c %d%c %d%c", [components day], ' ', [components hour], ' ', [components minute], ' ', [components second], ' ']];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
destinationDate = [[NSDate dateWithTimeIntervalSince1970:1343609103] retain];
timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(updateLabel) userInfo:nil repeats:NO];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
#end

Answer 1

set repeats YES to your timer.
[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(updateLabel) userInfo:nil repeats:YES];
edit: also consider using NSDateFormatter to display your string.
If you want to improve your layout, I would suggest using NSDateFormatter in conjunction with multiple UILabels. The date formatter can be used to create a string of the format you require and each label can hold a particular part of the date/time string. Take a look at Apple's Data Formatting Guide the most understated part is the link to the Unicode Technical Standard #35 which defines all the formats you can use.
Once you've split your date, you just have to layout your views as you like.