ios 如何获得系统时间和日期

//获得系统时间
NSDate *  senddate=[NSDate date];
NSDateFormatter  *dateformatter=[[NSDateFormatter alloc] init];
[dateformatter setDateFormat:@"HH:mm"];
NSString *  locationString=[dateformatter stringFromDate:senddate];
//[dateformatter setDateFormat:@"YYYY-MM-dd-HH-mm-ss"];
//NSString *  morelocationString=[dateformatter stringFromDate:senddate];

//获得系统日期
NSCalendar  * cal=[NSCalendar  currentCalendar];
NSUInteger  unitFlags=NSDayCalendarUnit|NSMonthCalendarUnit|NSYearCalendarUnit;
NSDateComponents * conponent= [cal components:unitFlags fromDate:senddate];
NSInteger year=[conponent year];
NSInteger month=[conponent month];
NSInteger day=[conponent day];
NSString *  nsDateString= [NSString  stringWithFormat:@"%4d年%2d月%2d日",year,month,day];

[dateformatter release];

2. 从字符串来获得NSDate

string  strYear="1988";
string  strMonth="09";
string  strDay="18";
string  strHour="5";
string  strMinutes="18";
string  strSec="20";



morelocationString=[NSString stringWithFormat:@"%s-%s-%s-%s-%s-%s",strYear.c_str(),strMonth.c_str(),
                                strDay.c_str(),strHour.c_str(),strMinutes.c_str(),strSec.c_str()];


            //根据时间字符串获得NSDate
            NSDateFormatter  *dateformatter=[[NSDateFormatter alloc] init];
            [dateformatter setDateFormat:@"YYYY-MM-dd-HH-mm-ss"];
            NSDate  * oldDate=[dateformatter dateFromString:morelocationString];

3. 从GMT时间，得到本地时间

NSDate  * oldDate=[dateformatter dateFromString:morelocationString];


            NSTimeInterval  timeZoneOffset=[[NSTimeZone systemTimeZone] secondsFromGMT];
            NSDate  * newDate=[oldDate dateByAddingTimeInterval:timeZoneOffset];

原文链接:

http://blog.csdn.net/tangaowen/article/details/6525915