如何从uipicker在Xcode中获取选定时区的日期和时间

Question

我试图从标签或文本字段中的uipicker显示选定时区的日期和时间我没有得到任何方法来解决此问题，所以请任何人帮助我提前致谢。

SelectedTimeZone = [Weight objectAtIndex：[pickerView selectedRowInComponent：0]]; NSString * selectedzone = SelectedTimeZone;

NSCalendar *gregorian=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; 
[gregorian setTimeZone:[NSTimeZone timeZoneWithName:selectedzone]]; 
NSDateComponents *timeZoneComps=[[NSDateComponents alloc] init]; 

NSDate *date=[gregorian dateFromComponents:timeZoneComps]; 
NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
[formatter setDateStyle:NSDateFormatterFullStyle]; 
[formatter setDateFormat:@"dd-MM-yyyy HH:mm:ss "]; 
NSString *todaysDate= [formatter stringFromDate:[NSDate date]]; 
zone.text = todaysDate; I know this is not proper way but i'm new to xcode 

Answer 1

[NSDate的日期]返回表示当前的日期和时间的日期对象，无论在哪里你是。 NSDates不受地点或时区的限制。只有一个NSDate代表现在或任何其他时刻，而不是每个时区的不同日期对象。因此，您不应尝试在时区之间转换日期。

NSDate *now = [NSDate date]; 
NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
[formatter setDateStyle:NSDateFormatterShortStyle]; 
[formatter setTimeStyle:NSDateFormatterShortStyle]; 
[formatter setTimeZone:[NSTimeZone timeZoneWithName:@"Australia/Sydney"]]; 
NSLog(@"%@",[formatter stringFromDate:now]); //--> 9/9/11 11:54 PM 
[formatter setTimeZone:[NSTimeZone timeZoneWithName:@"Europe/Paris"]]; 
NSLog(@"%@",[formatter stringFromDate:now]); 

或者Refer same question here

Answer 2

要获得日期和所选时区的时间从uipicker提供日期到格式器是这样的：

NSDate *now = [NSDate date]; 
NSCalendar *gregorian=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; 
[gregorian setTimeZone:[NSTimeZone timeZoneWithName:selectedzone]]; 

NSDateComponents* timeZoneComps = [gregorian components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit|NSTimeZoneCalendarUnit fromDate:now]; 

NSDate *selectedDate=[gregorian dateFromComponents:timeZoneComps]; 
NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
[formatter setDateStyle:NSDateFormatterFullStyle]; 
[formatter setDateFormat:@"dd-MM-yyyy HH:mm:ss "]; 
NSString *strSelectedDate= [formatter stringFromDate:selectedDate]; 
zone.text = strSelectedDate;