iphone sdk更新时间

Question

我正在使用下面提供的代码来显示时间和日期。谁能帮我自动更改时间（按秒）和日期（按天）？

NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"yyyy-MM-dd"];

NSDateFormatter *timeFormat = [[NSDateFormatter alloc] init];
[timeFormat setDateFormat:@"HH:mm:ss"];

NSDate *now = [[NSDate alloc] init];

NSString *theDate = [dateFormat stringFromDate:now];
NSString *theTime = [timeFormat stringFromDate:now];

NSLog(@"\n"

      "theDate: |%@| \n"
      "theTime: |%@| \n"
      , theDate, theTime);

[dateFormat release];
[timeFormat release];
[now release];

Answer 1

具体来说，您可以使用 NSTimer ScheduledTimerWithTimeInterval：目标：选择器：用户信息：重复：. 。您可以使用 1 作为时间间隔。

Answer 2

使用NSDateComponents类。例如，为一天和至少一个第二添加到日期：

NSDate *startDate = [NSDate date];
unsigned unitFlags = NSDayCalendarUnit | NSSecondCalendarUnit;

NSCalendar *curr = [NSCalendar currentCalendar];
NSDateComponents *oneDay = [[NSDateComponents alloc] init];
oneDay.day = 1;
oneDay.second = 1;

NSDate* adjustedDate = [curr dateByAddingComponents:oneDay 
                                             toDate:startDate 
                                            options:0]; 

Answer 3

日期和时间编程指南