ios - 如何将 UTC 日期字符串转换为本地时间 (systemTimeZone)

Question

输入字符串：2012 年 6 月 14 日 - 01:00:00 UTC

输出本地字符串：2012 年 6 月 13 日 - 21:00:00 EDT

我喜欢从

NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
NSLog(@"Time Zone: %@", destinationTimeZone.abbreviation);

有什么建议吗？

Answer 1

这应该做你需要的：

NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"LLL d, yyyy - HH:mm:ss zzz";
NSDate *utc = [fmt dateFromString:@"June 14, 2012 - 01:00:00 UTC"];
fmt.timeZone = [NSTimeZone systemTimeZone];
NSString *local = [fmt stringFromDate:utc];
NSLog(@"%@", local);

请注意，您的示例不正确：UTC 时间 6 月 14 日凌晨 1 点，美国东部标准时间 6 月 13 日仍然是 6 月 13 日，标准时间晚上 8 点或夏令时晚上 9 点。在我的系统上，这个程序打印

Jun 13, 2012 - 21:00:00 EDT

Answer 2

斯威夫特 3

var dateformat = DateFormatter()
dateformat.dateFormat = "LLL d, yyyy - HH:mm:ss zzz"
var utc: Date? = dateformat.date(fromString: "June 14, 2012 - 01:00:00 UTC")
dateformat.timeZone = TimeZone.current
var local: String = dateformat.string(from: utc)
print(local)

Swift 4 : 日期扩展 UTC 或 GMT ⟺ 本地

//UTC or GMT ⟺ Local 

extension Date {

    // Convert local time to UTC (or GMT)
    func toGlobalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = -TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

    // Convert UTC (or GMT) to local time
    func toLocalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

}

Answer 3

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.dateFormat = @"MMMM d, yyyy - HH:mm:ss zzz"; // format might need to be modified

NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
[dateFormatter setTimeZone:destinationTimeZone];

NSDate *oldTime = [dateFormatter dateFromString:utcDateString];

NSString *estDateString = [dateFormatter stringFromDate:oldTime];

Answer 4

这从 GMT 转换为本地时间，您可以将其修改为 UTC 时间

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
dateFormatter.dateFormat = @"yyyy-MM-dd'T'HH:mm";

NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:@"GMT"]; 
[dateFormatter setTimeZone:gmt]; 
NSString *timeStamp = [dateFormatter stringFromDate:[NSDate date]]; 
[dateFormatter release];

取自iPhone：NSDate 将 GMT 转换为本地时间

Answer 5

func timeConverter() -> 
{
    let zone = TimeZone.current
    let sec = -TimeInterval(zone.secondsFromGMT(for: self)
    return Date(timeInterval: sec , since : self)
}