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