iOS NSDate 时间日期

近来用到时间空间，整理一些可能用到的处理NSDate的方法和大家分享，有什么不足的欢迎大家补充。

//获取当前时间前后几年几月几天的时间year＝1是当前时间的后一年year＝－1时当前的前一年，月和日也是一样

-(void)getTime

{

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

NSDateComponents *comps = nil;

comps = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:[NSDate date]];

NSDateComponents *adcomps = [[NSDateComponents alloc] init];

[adcomps setYear:year];

[adcomps setMonth:month];

[adcomps setDay:day];

NSDate *newdate = [calendar dateByAddingComponents:adcomps toDate:[NSDate date] options:0];

NSDateFormatter *pickerFormatter = [[NSDateFormatter alloc] init];// 创建一个日期格式器

[pickerFormatter setDateFormat:@"yyyy-MM"];

NSString *dateString = [pickerFormatter stringFromDate:newdate];

return dateString;

}

比较时间的大小

[localDate compare:date8]==NSOrderedDescending 

 [localDate compare:date20]==NSOrderedAscending

NSOrderedSame

比较，取得更早或更晚的日期:

NSDate *d = [date1 earlierDate: date2];

NSDate *d = [date1  laterDate: date2]

是否相同日期:

BOOL b = [date1 isEqualToDate: date2];

从某时间开始经过某秒后的日期时间:

bDate = [aDate initWithTimeInterval:3*60  sinceDate:aDate]; //从aDate过3分钟

指定某月的末日: (使用前一个月的第一天来取得)

NSDate *aDate = [inputDateFormatter dateFromString:@"2000/03/01 00:00:00"]; //给定3月1日零点日期

NSDate *bDate = [orgDate initWithTimeInterval:-1*24*60*60  sinceDate:a];// 1日前

NSLog(@"2000年2月的末日 -> %@", bDate);

取得某两个时间相隔多久:

since = [dateA timeIntervalSinceDate: dateB];

只取得日期不要时间:

NSDateFormatter *df = [[NSDateFormatter alloc] init];

[df setTimeStyle: NSDateFormatterNoStyle];

[df setDateStyle: NSDateFormatterMediumStyle];

NSString *nowDateStr = [df stringFromDate:[NSDate date]];

NSDate *nowDate = [df dateFromString:nowDateStr];

NSLog(@"%@", nowDate);

2.获取当前所处时区

NSTimeZone *zone = [NSTimeZone systemTimeZone];

NSLog(@"now = %@", zone);

3.获取当前时区和指定时间差

NSInteger seconds = [zone secondsFromGMTForDate:date];

NSLog(@"seconds = %lu", seconds);

NSDate *nowDate = [date dateByAddingTimeInterval:seconds];

NSLog(@"nowDate = %@", nowDate);

//比较两个日期的差值

// 时间字符串

NSString *str = @"2012-03-11 06:44:11 +0800";

// 1.创建一个时间格式化对象

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

// 2.格式化对象的样式/z大小写都行/格式必须严格和字符串时间一样

formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss Z";

// 3.字符串转换成时间/自动转换0时区/东加西减

NSDate *date = [formatter dateFromString:str];

NSDate *now = [NSDate date];

// 注意获取calendar,应该根据系统版本判断

NSCalendar *calendar = [NSCalendar currentCalendar];

NSCalendarUnit type = NSCalendarUnitYear |

NSCalendarUnitMonth |

NSCalendarUnitDay |

NSCalendarUnitHour |

NSCalendarUnitMinute |

NSCalendarUnitSecond;

// 4.获取了时间元素

NSDateComponents *cmps = [calendar components:type fromDate:date toDate:now options:0];

NSLog(@"%ld年%ld月%ld日%ld小时%ld分钟%ld秒钟", cmps.year, cmps.month, cmps.day, cmps.hour, cmps.minute, cmps.second);