1，创建时间。
NSDate *todaysDate = [NSDate date];
NSLog(@"Today‘s date is %@", todaysDate);
后面的+0000很讨厌。
2，由组建创建时间段，比如年月日，十分秒。
timeZoneWithAbbreviation设置时区。
具体代码
NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
dateComponents.year = 2007;
dateComponents.month = 6;
dateComponents.day = 29;
dateComponents.hour = 12;
dateComponents.minute = 01;
dateComponents.second = 31;
dateComponents.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
NSDate *iPhoneReleaseDate = [[NSCalendar currentCalendar] dateFromComponents:dateComponents];
NSLog(@"The original iPhone went on sale: %@", iPhoneReleaseDate);
3，比较两个时区。
比如看看是不是今天。
NSDate *todaysDate = [NSDate date];
if([todaysDate isEqualToDate:iPhoneReleaseDate])
NSLog(@"The iPhone was released today!");
else
NSLog(@"The iPhone was released on some other date”);
早一天或晚一天。
NSDate *earlierDateIs = [todaysDate earlierDate:iPhoneReleaseDate];
NSDate *laterDateIs = [todaysDate laterDate:iPhoneReleaseDate];
日历
NSCalendar *systemCalendar = [NSCalendar currentCalendar];
unsigned int unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |
NSDayCalendarUnit;
具体代码
NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
dateComponents.year = 2007;
dateComponents.month = 6;
dateComponents.day = 29;
dateComponents.hour = 12;
dateComponents.minute = 01;
dateComponents.second = 31;
dateComponents.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"PDT"];
NSDate *iPhoneReleaseDate = [[NSCalendar currentCalendar] dateFromComponents:dateComponents];
NSLog(@"The original iPhone went on sale: %@", iPhoneReleaseDate);
NSDate *todaysDate = [NSDate date];
NSLog(@"Today‘s date is: %@", todaysDate);
if([todaysDate isEqualToDate:iPhoneReleaseDate])
NSLog(@"The iPhone was released today!");
else
NSLog(@"The iPhone was released on some other date");
NSDate *earlierDateIs = [todaysDate earlierDate:iPhoneReleaseDate];
NSLog(@"The earlier date is: %@", earlierDateIs);
NSDate *laterDateIs = [todaysDate laterDate:iPhoneReleaseDate];
NSLog(@"The later date is: %@", laterDateIs);
NSTimeInterval timeBetweenDates = [todaysDate timeIntervalSinceDate:iPhoneReleaseDate];
NSLog(@"The iPhone was released %f seconds ago", timeBetweenDates);
NSCalendar *systemCalendar = [NSCalendar currentCalendar];
unsigned int unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit| NSDayCalendarUnit;
NSDateComponents *dateComparisonComponents = [systemCalendar components:unitFlags
fromDate:iPhoneReleaseDate toDate:todaysDate
options:NSWrapCalendarComponents];
NSLog(@"The iPhone was released %ld years, %ld months and %ld days ago",
dateComparisonComponents.year,
dateComparisonComponents.month,
dateComparisonComponents.day
);
你可以比较出差多少十分秒，年月日等。
4，字符串转换成日期。
NSString *dateString = @"02/14/2012";
NSDateFormatter *df = [[NSDateFormatter alloc] init];
df.dateFormat = @"MM/dd/yyyy";
NSDate *valentinesDay = [df dateFromString:dateString];
NSLog(@"Valentine‘s Day = %@", valentinesDay);
用dateFromString:dateString就行了。
5，
按一定格式格式化日期。
NSString *dateString = @"02/14/2012";
NSDateFormatter *df = [[NSDateFormatter alloc] init];
df.dateFormat = @"MM/dd/yyyy";
NSDate *valentinesDay = [df dateFromString:dateString];
NSLog(@"Unformatted Valentine‘s Day = %@", valentinesDay);
NSLog(@"Formatted Valentine‘s Day = %@", [df stringFromDate:valentinesDay]);
df.dateFormat = @"EEEE, MMMM d";
NSLog(@"Another Formatted Valentine‘s Day = %@", [df stringFromDate:valentinesDay]);
6，加减日期。
代码，
NSString *dateString = @"02/14/2012";
NSDateFormatter *df = [[NSDateFormatter alloc] init];
df.dateFormat = @"MM/dd/yyyy";
NSDate *valentinesDay = [df dateFromString:dateString];
NSLog(@"Valentine‘s Day = %@", valentinesDay);
NSDateComponents *weekBeforeDateComponents = [[NSDateComponents alloc] init];
weekBeforeDateComponents.week = -1;
NSDate *vDayShoppingDay = [[NSCalendar currentCalendar] dateByAddingComponents:weekBeforeDateComponents
toDate:valentinesDay
options:0];
NSLog(@"Shop for Valentine‘s Day by %@", vDayShoppingDay);
由于日期是对象，操作日期的相关属性即可，
7，使用定时器安排或重复任务。就是你想要一段代码在特定时期执行。
先弄一个日期对象
NSDate *scheduledTime = [NSDate dateWithTimeIntervalSinceNow:10.0];
创建计时器。
NSString *customUserObject = @"To demo userInfo";
NSTimer *timer = [[NSTimer alloc] initWithFireDate:scheduledTime
interval:2
target:self
selector:@selector(task)
userInfo:customUserObject
repeats:YES];
循环运行，添加时间。
NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
[runLoop addTimer:timer forMode:NSDefaultRunLoopMode];
具体代码
#import "AppDelegate.h"
@implementation AppDelegate
@synthesize window = _window;
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification{
NSDate *scheduledTime = [NSDate dateWithTimeIntervalSinceNow:10.0];
NSString *customUserObject = @"To demo userInfo";
NSTimer *timer = [[NSTimer alloc] initWithFireDate:scheduledTime
interval:2
target:self
selector:@selector(task:)
userInfo:customUserObject
repeats:YES];
NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
[runLoop addTimer:timer
forMode:NSDefaultRunLoopMode];
}
-(void)task:(id)sender{
NSTimer *localTimer = (NSTimer *)sender;
NSLog(@"Schedule task has executed with this user info: %@", [localTimer userInfo]);
}
@end
自己建立，是mac应用，不是IOS应用。
原文地址：http://www.cnblogs.com/guanliyang/p/3914708.html
