iOS:将UTC时区转换为设备本地时区

Question

我正在尝试将以下时区转换为设备本地时区：

2013-08-03T05:38:39.590Z

请告诉我如何将其转换为本地时区。

我该怎么做？

Answer 1

时区可以应用于NSDateFormatter，从中可以生成按时差区分的NSDate变量。

NSString* input = @"2013-08-03T05:38:39.590Z";
NSString* format = @"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
// Set up an NSDateFormatter for UTC time zone
NSDateFormatter* formatterUtc = [[NSDateFormatter alloc] init];
[formatterUtc setDateFormat:format];
[formatterUtc setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
// Cast the input string to NSDate
NSDate* utcDate = [formatterUtc dateFromString:input];
// Set up an NSDateFormatter for the device's local time zone
NSDateFormatter* formatterLocal = [[NSDateFormatter alloc] init];
[formatterLocal setDateFormat:format];
[formatterLocal setTimeZone:[NSTimeZone localTimeZone]];
// Create local NSDate with time zone difference
NSDate* localDate = [formatterUtc dateFromString:[formatterLocal stringFromDate:utcDate]];
NSLog(@"utc:   %@", utcDate);
NSLog(@"local: %@", localDate);
[formatterUtc release];
[formatterLocal release];

Answer 2

这样尝试：

   NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
   [dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
   [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
   NSDate* utcTime = [dateFormatter dateFromString:@"2013-08-03T05:38:39.590Z"];
   NSLog(@"UTC time: %@", utcTime);
   [dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
   [dateFormatter setDateFormat:@"M/d/yy 'at' h:mma"];
   NSString* localTime = [dateFormatter stringFromDate:utcTime];
   NSLog(@"localTime:%@", localTime);  

希望它能帮助你。。。。