日期/时间转换为用户的本地时间 - 问题

Question

我的应用程序从始终处于GMT +1 (UTC/GMT +1小时)时区的远程服务器获取日期/时间。

服务器提供的格式是:

24 08 2011 08:45PM

我想把这个时间戳转换成用户所在时区的等效时间/日期(用户可以在世界上任何地方)

以

为例:24 08 2011 08:45PM来自服务器应该呈现

24 08 2011 09:45PM to an Italian user (rome) (GMT + 1)

这段代码可以在某些时区工作，但我有一种不好的感觉，这是非常错误的，有一个更优雅的方式来做

NSString *dateString = @"24 08 2011 09:45PM";
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
     [dateFormatter setDateFormat:@"dd MM yyyy hh:mma"];
    NSDate *dateFromString = [[[NSDate alloc] init] autorelease];
    dateFromString = [dateFormatter dateFromString:dateString];

    NSDate* sourceDate = dateFromString;
    NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"BST"];
    NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
    NSInteger sourceGMTOffset = [sourceTimeZone secondsFromGMTForDate:sourceDate];
    NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:sourceDate];
    NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;
    NSDate* destinationDate = [[NSDate alloc] initWithTimeInterval:interval sinceDate:sourceDate] ;
    NSString *thePubDate =  [dateFormatter stringFromDate:destinationDate];//[appLogic getPubDate];
    NSLog(@"Result : %@",thePubDate);
    [dateFormatter release];
    //[dateFromString release];
    [destinationDate release];

非常感谢您对此事的意见和建议

Answer 1

只需在dateFormatter中设置时区，此代码就足够了

NSString *dateString = @"24 08 2011 09:45PM";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd MM yyyy hh:mma"];
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"BST"];
[dateFormatter setTimeZone:sourceTimeZone];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];

dateFromString现在将具有日期24 08 2011 08:45PM(GMT)..然后，要将其转换为具有本地时间的字符串，只需编写以下代码

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd MM yyyy hh:mma"];
NSString *stringFromDAte = [dateFormatter stringFromDate:dateString];