iPhone：NSDate 将 GMT 转换为当地时间

Question

目前，我有一个 API 调用返回一个日期/时间，格式如下：2010-10-10T07:54:01.878926

我可以假设这是 GMT 吗？我还将其转换为 NSDate 对象。有没有办法使用iPhone本地时间重新计算时间？

Answer 1

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];

Answer 2

此代码会将 GMT 时间转换为设备的本地时间。

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

Answer 3

NSDate *sourceDate = [NSDate dateWithTimeIntervalSince1970:gmtTimestamp];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
NSInteger sourceGMTOffset = [destinationTimeZone secondsFromGMTForDate:0];
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:sourceDate];
NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;
NSDate* destinationDate = [[[NSDate alloc] initWithTimeInterval:interval sinceDate:sourceDate] autorelease];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.dateFormat = @"yyyy-MM-dd'T'HH:mm";
[dateFormatter setTimeZone:destinationTimeZone];
NSString *localTimeString = [dateFormatter stringFromDate:destinationDate];

Answer 4

NSDate *now = [NSDate date];
NSLog(@"%@", [now dateWithCalendarFormat:@"%Y-%m-%d %H:%M:%S" 
              timeZone:[NSTimeZone timeZoneWithName:@"GMT"]]);