iOS 获取当前时间并且显示走在视图上

//  时间戳在走并且显示Demo

#import "RootViewController.h"

@interface RootViewController ()
{

    UILabel *labelTime;
    NSTimer *timeNow;

}

@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor orangeColor];

    labelTime = [[UILabel alloc] initWithFrame:CGRectMake(60, 100, 200, 50)];
    labelTime.backgroundColor = [UIColor redColor];

    [self.view addSubview:labelTime];
    timeNow = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(timerFunc) userInfo:nil repeats:YES];

    //获取系统时间
    NSDate *  senddate=[NSDate date];
    NSDateFormatter  *dateformatter=[[NSDateFormatter alloc] init];
    [dateformatter setDateFormat:@"HH:mm"];
    NSString *  locationString=[dateformatter stringFromDate:senddate];
    NSLog(@"-------%@",locationString);
    //获取系统时间
    NSCalendar  * cal=[NSCalendar  currentCalendar];
    NSUInteger  unitFlags=NSDayCalendarUnit|NSMonthCalendarUnit|NSYearCalendarUnit;
    NSDateComponents * conponent= [cal components:unitFlags fromDate:senddate];
    NSInteger year=[conponent year];
    NSInteger month=[conponent month];
    NSInteger day=[conponent day];
    NSString *  nsDateString= [NSString  stringWithFormat:@"%4d年%2d月%2d日",year,month,day];
    NSLog(@"+++++++++++++%@",nsDateString);
}
- (void)timerFunc
{

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    [formatter setDateFormat:@"MM/dd/YY HH:mm:ss"];

    NSString *timestamp = [formatter stringFromDate:[NSDate date]];

    [labelTime setText:timestamp];//时间在变化的语句

    NSLog(@"%@",timestamp);




}

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

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end