ios 如何获取上午/下午格式的时间 iphone NSDateFormatter？

How to get the time in am/pm format iphone NSDateFormatter?

提问by Gopinath

Am working in an iPhone app with using the NSDateFormatter. Am getting the time from the webservice like "00:00:00", "16:00:00","15:30:00" and so on. I need to convert these time to if the time is "00:00:00" to "12 AM", if the time is "16:00:00" to "4 PM", if the time is "15:30:00" to "3.30 PM". I have used the below code to this but when i have pass "16:00:00" the date returns null.

我在使用 NSDateFormatter 的 iPhone 应用程序中工作。我从像"00:00:00", "16:00:00","15:30:00" and so on. 我需要将这些时间转换为如果时间是"00:00:00" to "12 AM"，如果时间是"16:00:00" to "4 PM"，如果时间是“15:30:00”到“3.30 PM”。我已经使用了下面的代码，但是当我通过时"16:00:00" the date returns null。

 NSString *dats1 = @"16:00:00";
 NSDateFormatter *dateFormatter3 = [[[NSDateFormatter alloc] init] autorelease];
 [dateFormatter3 setDateStyle:NSDateFormatterMediumStyle];  
 [dateFormatter3 setDateFormat:@"hh:mm:ss"]; 
 NSDate *date1 = [dateFormatter3 dateFromString:dats1];
 NSLog(@"date1 : %@", date1); **// Here returning (null)**

 NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
 [formatter setDateFormat:@"hh:mm a"];
 NSLog(@"Current Date: %@", [formatter stringFromDate:date1]); **// Here also returning (null)**
 [formatter release];

When am passing "00:00:00" it is returning "12 AM" correctly. Can anyone please help me to solve this issue? Thanks in advance.

当我通过“00:00:00”时，它会正确返回“12 AM”。任何人都可以帮我解决这个问题吗？提前致谢。

回答by Yuvaraj.M

If your time format is in 24hrsplease use "HH:mm:ss"format. Please test the code and let me know if it is working for you. I have tested and it is returning "4 PM"

如果您的时间格式是在24hrs请使用"HH:mm:ss"格式。请测试代码，让我知道它是否适合您。我已经测试过了，它正在返回"4 PM"

NSString *dats1 = @"16:00:00";
 NSDateFormatter *dateFormatter3 = [[[NSDateFormatter alloc] init] autorelease];
 [dateFormatter3 setDateStyle:NSDateFormatterMediumStyle];  
 [dateFormatter3 setDateFormat:@"HH:mm:ss"]; 
 NSDate *date1 = [dateFormatter3 dateFromString:dats1];
 NSLog(@"date1 : %@", date1); **// Here returning (null)**

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
 [formatter setDateFormat:@"hh:mm a"];
 NSLog(@"Current Date: %@", [formatter stringFromDate:date1]); **// Here also returning (null)**
 [formatter release];

Thanks.

谢谢。

回答by eliocs

You can use the .ShortStylewhich will adapt to the current locale:

您可以使用.ShortStyle将适应当前语言环境的 ：

let timeFormatter = NSDateFormatter()
timeFormatter.dateStyle = .NoStyle
timeFormatter.timeStyle = .ShortStyle
timeFormatter.stringFromDate(NSDate())

Which returns 17:12or 5:12 PMdepending on the current device locale.

返回17:12或5:12 PM取决于当前设备区域设置。

回答by Charan

Why are you again allocating the NSDateFormatter?

你为什么要再次分配NSDateFormatter？

you Just need to format it to NSDateand then again to NSString,

你只需要将它格式化为NSDate然后再次格式化NSString，

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

    NSDate *date = [dateFormatter dateFromString:dats1];

    [dateFormatter setDateFormat:@"hh:mm a"];

    NSString *formattedDate = [dateFormatter stringFromDate:date];

    NSLog(@"%@",formattedDate);

回答by Steven Kramer

Try HH:mm:ss(notice the capitals in the hour format)

尝试HH:mm:ss（注意小时格式的大写字母）

回答by Rafat touqir Rafsun

Hope someone would be helpful who would like to get it in Swift

希望有人会帮助想在 Swift 中获得它的人

For Swift

对于斯威夫特

let dateFormatter = NSDateFormatter()
//if some one want 12AM,5PM then use "hh mm a"
//if some one want 00AM,17PM then use "HH mm a"
dateFormatter.dateFormat = "hh mm a"
let stringDate = dateFormatter.stringFromDate(NSDate())
println(stringDate)

回答by Mutablegopi

This Below code always keep in 12hour format:

下面的代码始终保持 12 小时格式：

NSLocale *12hourFomrat = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
df.locale = 12hourFomrat;

This always keep in 24 hour format

这始终保持在 24 小时格式

NSLocale *24hourFormat = [[NSLocale alloc] initWithLocaleIdentifier:@"en_GB"];
df.locale = 24hourFormat

回答by CarlJ

your date format should be:

你的日期格式应该是：

  [dateFormatter3 setDateFormat:@"HH:mm:ss"]; 

check the Date Format Pattern Doku

检查日期格式模式 Doku

回答by Sreedeepkesav M S

Swift 5:

斯威夫特 5：

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "hh mm a"
let formattedDate = dateFormatter.string(from: Date())