做的东西随便上传

#import "ShowTimeViewController.h"

@interface ShowTimeViewController ()

@property (weak, nonatomic) IBOutlet UIButton *btnBigen;
@property (weak, nonatomic) IBOutlet UILabel *lbShowTime;

@property ( nonatomic ) BOOL isRunning ;

@property ( strong , strong) NSTimer *  curtimer ;

@property ( nonatomic) int  curInt ;

@end

@implementation ShowTimeViewController


- (IBAction)clickBegin:(id)sender {
    if( self.isRunning)
    {
        //  pause
        [self.curtimer invalidate];
        self.isRunning = NO ;
        
        [self.btnBigen setTitle:@"开始" forState:UIControlStateNormal ] ;
    }else
    {
        //  run
        
        self.isRunning = YES ;
        
     self.curtimer =   [NSTimer scheduledTimerWithTimeInterval:0.001 target:self selector:@selector(updateTime) userInfo:nil repeats:YES];
        
        [self.btnBigen setTitle:@"暂停" forState:UIControlStateNormal ] ;
    }
}

-(void) updateTime
{
    self.curInt ++ ;
    
    int  time =  self.curInt ;
    
    
    int min =  time   /( 1000 * 60  ) ;
    int second =  (time - min * 1000 * 60)  /1000  ;
    int ms =  time - min * 1000 * 60 - second * 1000 ;
    
    self.lbShowTime.text = [NSString stringWithFormat:@"%02d:%02d %03d" , min , second , ms];
}


- (IBAction)clickReset:(id)sender {
   // reset
    [self.curtimer invalidate];
    self.isRunning = NO ;
    self.lbShowTime.text = @"00:00 000" ;
    
    
    [self.btnBigen setTitle:@"开始" forState:UIControlStateNormal ] ;
}




- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

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