NSDate无法正常工作

Question

我希望每秒都获得当前但是当我实现这个概念时，NSTimer的时间没有变化，我的代码是

[NSTimer scheduledTimerWithTimeInterval:1 repeats:YES block:^(NSTimer *timer){
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setTimeZone:[NSTimeZone localTimeZone]];
    [formatter setDateFormat:@"YYYY-MM-DD HH:MM:SS"];
    NSDate *date = [NSDate date];
    NSString *dateTime = [formatter stringFromDate:date];

    NSLog(@"Date and Time :%@",dateTime);
}];

我的输出是时间也是错误的。

Answer 1

我认为当您尝试使用以下日期设置日期格式时出现错误：

[formatter setDateFormat:@"YYYY-MM-DD HH:MM:SS"];

我尝试过：

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setTimeZone:[NSTimeZone localTimeZone]];
[formatter setDateStyle:NSDateFormatterMediumStyle];
[formatter setTimeStyle:NSDateFormatterFullStyle];

我的输出是：

Date and Time :Jan 27, 2017, 8:05:50 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:51 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:52 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:53 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:54 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:55 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:56 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:57 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:58 PM Central European Standard Time
Date and Time :Jan 27, 2017, 8:05:59 PM Central European Standard Time

也许这个网站可以帮助您设置dateFormat：http://nsdateformatter.com

设置以下格式（小mm和ss）时：

[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

你看到正确的分钟和秒

Date and Time :2017-01-27 20:10:18
Date and Time :2017-01-27 20:10:19
Date and Time :2017-01-27 20:10:20
Date and Time :2017-01-27 20:10:21
Date and Time :2017-01-27 20:10:22