如何在iOS上获得当地时间

Question

我刚注意到NSDate *nowDate = [NSDate date];给了我GMT + 0时间而不是当地时间。所以基本上在我的iPad上是13:00，这段代码的输出是12:00。

如何正确获得当地时间？

Answer 1

试一试！

NSDate* sourceDate = [NSDate date];

NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];//use `[NSTimeZone localTimeZone]` if your users will be changing time-zones. 

NSInteger sourceGMTOffset = [sourceTimeZone secondsFromGMTForDate:sourceDate];
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:sourceDate];
NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;

NSDate* destinationDate = [[[NSDate alloc] initWithTimeInterval:interval sinceDate:sourceDate] autorelease];

它会根据当前系统时区为您提供时间。

Answer 2

NSDate不关心时区。它只记录一个时刻。

使用NSDateFormatter获取日期的字符串表示时，应设置本地时区：

NSDate *date = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle]; // Set date and time styles
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *dateString = [dateFormatter stringFromDate:date];

Answer 3

// get current date/time
NSDate *today = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
// display in 12HR/24HR (i.e. 11:25PM or 23:25) format according to User Settings
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
NSString *currentTime = [dateFormatter stringFromDate:today];
[dateFormatter release];
NSLog(@"%@",currentTime);

Answer 4

 NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
 [calendar setTimeZone:[NSTimeZone localTimeZone]];
 NSDateComponents *dateComponents = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:[NSDate date]];
 NSDate *d = [calendar dateFromComponents:dateComponents];