将GMT时间转换为当地时间

我现在得到GMT时间 – 2013-05-15 08:55 AM

我目前的当地时间是 – 2013-05-15 02:06 PM和时区是 – 亚洲/加尔各答

我试图用上面的代码把上面的GMT转换成我的本地时间

NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"Asia/Kolkata"]; [dateFormatter setTimeZone:sourceTimeZone]; // timeStamp - is the above GMT time NSDate *dateFromString = [dateFormatter dateFromString:timeStamp]; NSLog(@"local time is %@",dateFromString); 

但是这给我这个时间 – 2013-05-14 19:04:00 +0000而不是2013-05-14 02:06 PM

为什么会发生？ 请帮我明确这一点。提前感谢

Answer 1

没有什么是错误的，一个NSDate实例将永远不会有一个时区（好吧，但它总是格林尼治标准时间，由date描述+0000时区表示）。

你在代码中告诉dateformatter的是，你想parsing的date的时区是Asia/Kolkata但你希望它是GMT 。

首先，您需要根据input的datestring制作一个NSDate对象，将时区设置为您所指定的正确时区GMT 。

 NSTimeZone *gmtTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"]; [dateFormatter setTimeZone:sourceTimeZone]; NSDate *dateFromString = [dateFormatter dateFromString:timeStamp]; NSLog(@"Input date as GMT: %@",dateFromString); 

那么当你把date作为一个string使用时：

 NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithName:@"Asia/Kolkata"]; [dateFormatter setTimeZone:sourceTimeZone]; NSString *dateRepresentation = [dateFormatter stringFromDate:dateFromString]; NSLog(@"Date formated with local time zone: %@",dateRepresentation); 

Answer 2

我发现将GMT时间转换为当地时区的最短途径是

  NSDate* localDateTime = [NSDate dateWithTimeInterval:[[NSTimeZone systemTimeZone] secondsFromGMT] sinceDate:dateInGMT]; 

此外，将此date值转换为string

 NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat:@"HH:mm:ss"];//use the formatted as per your requirement. //Optionally for time zone converstions [formatter setTimeZone:[NSTimeZone timeZoneWithName:@"..."]]; NSString *localTimeDateString = [formatter stringFromDate:localDateTime]; 

Answer 3

 NSLog(@"local time is %@",[dateFormatter stringFromDate: dateFromString]); 

Answer 4

 NSTimeZone* gmtTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"]; NSTimeZone* localTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"Asia/Kolkata"]; NSDateFormatter *gmtDateFormatter = [[NSDateFormatter alloc] init]; [gmtDateFormatter setTimeZone:gmtTimeZone]; NSDate *date = [gmtDateFormatter dateFromString:timestamp]; NSDateFormatter *localDateFormatter = [[NSDateFormatter alloc] init]; [localDateFormatter setTimeZone:localTimeZone]; NSLog(@"local time is %@",[localDateFormatter stringFromDate:date]); 

Answer 5

使用timeZoneWithName

 NSDate *date=[[NSDate alloc]init]; NSDateFormatter *timeFormat = [[NSDateFormatter alloc] init]; [timeFormat setTimeZone:[NSTimeZone timeZoneWithName:@"Asia/Kolkata"]]; [timeFormat setDateFormat:@"HH:mm"]; NSString *dateStr=[timeFormat stringFromDate:date];