iOS NSDate 获取时区特定日期？

Question

我从 Web 服务获取 HH:mm:ss 格式的时间，它处于阿根廷 (GMT-3) 时区。我想将这个时间转换为完整日期 (dd-MM-yyyy HH:mm:ss)，最后将其转换为设备本地时区的日期。这是我的代码

-(NSString *)getLocalTimeStringFrom:(NSString *)sourceTime
{
    static NSDateFormatter* df = nil;
    static NSDateFormatter* df1 = nil;

    if (!df) {
        df = [[NSDateFormatter alloc]init];
        df.dateFormat = @"dd-MM-yyyy HH:mm:ss";

    }
    if (!df1) {

        df1 = [[NSDateFormatter alloc]init];
        df1.dateFormat = @"dd-MM-yyyy";
    }
    NSTimeZone *sourceZone = [NSTimeZone timeZoneWithAbbreviation:@"ART"];
    [df setTimeZone: sourceZone];
    [df1 setTimeZone: sourceZone];

     NSString *artDate = [df1 stringFromDate:[NSDate date]]; // get 29-09-2015
    NSString* timeStamp = [artDate stringByAppendingString:[NSString stringWithFormat:@" %@",sourceTime]]; // get 29-09-2015 00:05:00, if sourceTime is 00:05:00
    NSDate *art = [df dateFromString:timeStamp];
    NSLog(@"ART date %@" , art);//ART date 2015-09-29 03:05:00 +0000

    NSTimeZone *localTimeZone = [NSTimeZone systemTimeZone];
    [df setTimeZone: localTimeZone];
  NSLog(@"Local date %@" , [df stringFromDate: art]);

    return [df stringFromDate: ds];
}

问题是我在 art 中获取 UTC 日期(如代码中所注释)，请注意 art 的值为 2015-09-29 03 :05:00 +0000 是 UTC，格式是 yyyy-MM-dd HH:mm:ss，但应该是 ART 和 dd -MM-yyyy HH:mm:ss。我尝试了一些来自网络的代码，但没有得到解决方案。这段代码有什么问题？

Answer 1

我用这个:

NSDateFormatter* serverDf = [[NSDateFormatter alloc] init];
[serverDf setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:-3*60*60]];
[serverDf setDateFormat:@"dd-MM-yyyy HH:mm:ss"];
NSDate* gmtDate = [serverDf dateFromString:timeStamp];
//    DDLogVerbose(@"DateTime in GMT: %@", gmtDate);

NSDateFormatter* localDF = [[NSDateFormatter alloc] init];
[localDF setDateFormat:@"dd-MM-yyyy HH:mm:ss"];
[localDF setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"]];
NSString *localDate = [localDF stringFromDate:gmtDate];