Question

服务器提供UTC格式的日期和时间。

2012-11-28T10:32:15+01:00

utc将格式化为：2012-11-28 10:32:15 当前的实际当地日期和时间是2012-11-28 11:32:15

我想将utc格式保存在数据库中，稍后在UI中显示之前将其转换为用户的本地日期和时间。我写了以下代码。但是时间偏移是错误的。它会在utc时间增加2小时而不是1小时，尽管时间偏移是+ 1小时。

NSDateFormatter *utc = [[NSDateFormatter alloc] init];
[utc setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
[utc setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *dtUTC = [utc dateFromString:@"2012-11-28 10:32:15"];

double i =[[NSTimeZone systemTimeZone] secondsFromGMTForDate:[NSDate date ]];

NSDateFormatter *dfLocal = [[NSDateFormatter alloc] init];
[dfLocal setDateFormat:@"yy-MM-dd HH:mm:ss"];
[dfLocal setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:i]];
NSDate *localDateTime= [dtUTC dateByAddingTimeInterval:i];
NSString *time =[dfLocal stringFromDate:localDateTime];
NSLog(@"original UTC %@  now local: %@", dtUTC, time);

和日志：

time offset : 1.000000
original UTC 2012-11-28 10:32:15 +0000  now local: 12-11-28 12:32:15

它应该是2012-11-28 11:32:15但是会2012-11-28 12:32:15 我做错了什么？

Answer 1

发布问题后现在好了。我找到了解决方案。它的神奇！

NSDateFormatter *utc = [[NSDateFormatter alloc] init];
[utc setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
[utc setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *dtUTC = [utc dateFromString:@"2012-11-28 10:32:15"];

NSDateFormatter *dfLocal = [[NSDateFormatter alloc] init];
[dfLocal setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[dfLocal setTimeZone:[NSTimeZone localTimeZone]];

NSString *time =[dfLocal stringFromDate:dtUTC];
NSLog(@"original UTC %@  now local: %@", dtUTC, time);

和日志：

time offset : 1.000000
original UTC 2012-11-28 10:32:15 +0000  now local: **2012-11-28 11:32:15**

感谢各位帮忙

Answer 2

更改此行

[dfLocal setDateFormat:@"yy-MM-dd HH:mm:ss"];

并将其替换为

 [dfLocal setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

快乐编码。!!!!!

Answer 3

也尝试这段代码..

NSTimeZone* currentTimeZone = [NSTimeZone localTimeZone];
NSTimeZone* utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];

NSDate *dtUTC = [utc dateFromString:@"2012-11-28 10:32:15"];

NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:sourceDate];
NSInteger gmtOffset = [utcTimeZone secondsFromGMTForDate:sourceDate];
NSTimeInterval gmtInterval = gmtOffset - currentGMTOffset;

NSDateFormatter *dfLocal = [[NSDateFormatter alloc] init];
[dfLocal setDateFormat:@"yy-MM-dd HH:mm:ss"];
NSDate* localDateTime = [[[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:dtUTC] autorelease];
NSString *time =[dfLocal stringFromDate:localDateTime];
NSLog(@"original UTC %@  now local: %@", dtUTC, time);

我希望这可以帮助你...

utc和本地日期时间转换

3 个答案: