Countdown ViewController - example of simple countdown view

ViewController.m

//
//  ViewController.m
//  countdown

#import "ViewController.h"

@interface ViewController ()

@property (strong, nonatomic) IBOutlet UIView *container;
@property (strong, nonatomic) IBOutlet UILabel *label1;
@property (strong, nonatomic) IBOutlet UILabel *label2;
@property (assign) NSInteger counter;
@property (assign) CGRect topFrame;
@property (assign) CGRect inFrame;
@property (assign) CGRect bottomFrame;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.counter = 100;
    
    self.topFrame = CGRectMake(0, -240, 240, 240);
    self.inFrame = CGRectMake(0, 0, 240, 240);
    self.bottomFrame = CGRectMake(0, 240, 240, 240);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    [self setValues];
}

- (void)setValues
{
    self.counter--;
    
    if (self.counter == 0)
    {
        self.counter = 99;
    }
    
    self.label1.text = [NSString stringWithFormat:@"%2ld", self.counter];
    self.label1.frame = self.inFrame;
    self.label2.text = [NSString stringWithFormat:@"%2ld", self.counter - 1];
    self.label2.frame = self.topFrame;
    
    [self animate];
}

- (void)animate
{
    [UIView animateWithDuration:1.0 delay:0.1 usingSpringWithDamping:2.0 initialSpringVelocity:2.0 options:0 animations:^{
        
        self.label1.frame = self.bottomFrame;
        self.label2.frame = self.inFrame;
    } completion:^(BOOL finished) {
        [self setValues];
    }];
}


@end