我怎么能得到一个NSDate对象的年/月/日，没有其他信息?我意识到我可以用类似这样的东西来做这件事:
NSCalendar *cal = [[NSCalendar alloc] init];
NSDateComponents *components = [cal components:0 fromDate:date];
int year = [components year];
int month = [components month];
int day = [components day];
但是对于像获取NSDate的年/月/日这样简单的事情来说，这似乎是一大堆麻烦。还有其他解决办法吗?
当前回答
你可以使用NSDateFormatter获取NSDate的独立组件:
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"dd"];
myDayString = [df stringFromDate:[NSDate date]];
[df setDateFormat:@"MMM"];
myMonthString = [df stringFromDate:[NSDate date]];
[df setDateFormat:@"yy"];
myYearString = [df stringFromDate:[NSDate date]];
如果你想要得到月份的数字而不是缩写，请使用“MM”。如果你想获取整数，使用[myDayString intValue];
其他回答
我这样做....
NSDate * mydate = [NSDate date];
NSCalendar * mycalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSCalendarUnit units = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
NSDateComponents * myComponents = [mycalendar components:units fromDate:mydate];
NSLog(@"%d-%d-%d",myComponents.day,myComponents.month,myComponents.year);
iOS 8新增功能
ObjC
NSDate *date = [NSDate date];
NSInteger era, year, month, day;
[[NSCalendar currentCalendar] getEra:&era year:&year month:&month day:&day fromDate:date];
斯威夫特
let date = NSDate.init()
var era = 0, year = 0, month = 0, day = 0
NSCalendar.currentCalendar().getEra(&era, year:&year, month:&month, day:&day, fromDate: date)
斯威夫特
更简单的方法获得date的任何元素作为可选String。
extension Date {
// Year
var currentYear: String? {
return getDateComponent(dateFormat: "yy")
//return getDateComponent(dateFormat: "yyyy")
}
// Month
var currentMonth: String? {
return getDateComponent(dateFormat: "M")
//return getDateComponent(dateFormat: "MM")
//return getDateComponent(dateFormat: "MMM")
//return getDateComponent(dateFormat: "MMMM")
}
// Day
var currentDay: String? {
return getDateComponent(dateFormat: "dd")
//return getDateComponent(dateFormat: "d")
}
func getDateComponent(dateFormat: String) -> String? {
let format = DateFormatter()
format.dateFormat = dateFormat
return format.string(from: self)
}
}
let today = Date()
print("Current Year - \(today.currentYear)") // result Current Year - Optional("2017")
print("Current Month - \(today.currentMonth)") // result Current Month - Optional("7")
print("Current Day - \(today.currentDay)") // result Current Day - Optional("10")
如果你的目标是iOS 8+，你可以使用新的NSCalendar方便方法以更简洁的格式实现这一点。
首先创建一个NSCalendar并使用所需的NSDate。
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *date = [NSDate date];
你可以通过component:fromDate单独提取组件:
NSInteger year = [calendar component:NSCalendarUnitYear fromDate:date];
NSInteger month = [calendar component:NSCalendarUnitMonth fromDate:date];
NSInteger day = [calendar component:NSCalendarUnitDay fromDate:date];
或者，更简洁地，通过getEra使用NSInteger指针:year:month:day:fromDate:
NSInteger year, month, day;
[calendar getEra:nil year:&year month:&month day:&day fromDate:date];
要了解更多信息和示例，请查看iOS 8中简化的NSDate操作。免责声明，这是我写的文章。
试试下面的方法:
NSString *birthday = @"06/15/1977";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MM/dd/yyyy"];
NSDate *date = [formatter dateFromString:birthday];
if(date!=nil) {
NSInteger age = [date timeIntervalSinceNow]/31556926;
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:date];
NSInteger day = [components day];
NSInteger month = [components month];
NSInteger year = [components year];
NSLog(@"Day:%d Month:%d Year:%d Age:%d",day,month,year,age);
}
[formatter release];
