如何将.hour（）和.minute（）从Swift转换为Objective-C？

如何将.minute（）和.hour（）转换为Objective-C

func nearestHour () -> Int {
    let halfHour = NSDate.minuteInSeconds() * 30
    var interval = self.timeIntervalSinceReferenceDate
    if  self.seconds() < 30 {
        interval -= halfHour
    } else {
        interval += halfHour
    }
    let date = NSDate(timeIntervalSinceReferenceDate: interval)
    return date.hour()
}

---

NSDate没有可见的@interface声明选择器小时。

如前所述，NSDate没有您需要的界面。您需要将其拆分为日历界面。然后，您可以单独设置小时/分钟/秒等，或者获取它们或您需要执行的任何操作

NSDateComponents *components = [[NSCalendar currentCalendar] components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:self];

if ([components seconds] < 30) {

NSDateComponents*components=[[NSCalendar currentCalendar]components:（NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit）fromDate:self]；
如果（[组件秒]<30）{

例如：

- (int) nearestHour {
    NSDateComponents *components = [[NSCalendar currentCalendar] components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:self];
    NSInteger halfHour = [NSDate minuteInSeconds].intValue * 30;
    NSTimeInterval interval = [self timeIntervalSinceReferenceDate];
    if ([components minutes] < 30) {
        interval -= halfHour;
    }
    else {
        interval += halfHour;
    }
    NSDate *date = [NSDate dateWithTimeIntervalSinceReferenceDate:    interval];
    return [date hour];
}

-（int）最近一小时{
NSDateComponents*components=[[NSCalendar currentCalendar]components:（NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit）fromDate:self]；
NSInteger半小时=[NSDate MINUTEINSECONS].intValue*30；
NSTimeInterval interval=[self-timeIntervalSinceReferenceDate]；
如果（[组件分钟]<30）{
间隔时间-=半小时；
}
否则{
间隔时间+=半小时；
}
NSDate*date=[NSDate date WITHTIMEIntervalsIncerenceDate:interval]；
返回[日期小时]；
}

SO和google上有很多例子：

---

苹果公司建议始终使用

NSCalendar

进行日期计算，因为例如，当夏令时发生变化时，通过加减秒计算的某些日期可能不存在

nextDateAfterDate

根据指定的日期组件计算下一个日期，在本例中为分钟为零的下一个日期。若要获取过去最近的小时数，还可以向后搜索

Swift

let now = NSDate()
let calendar = NSCalendar.currentCalendar()
let roundDown = calendar.component(.Minute, fromDate: now) < 30
let components = NSDateComponents()
components.minute = 0
let options : NSCalendarOptions = roundDown ? [.MatchNextTime, .SearchBackwards] : .MatchNextTime
let nearestDate = calendar.nextDateAfterDate(now, matchingComponents: components, options:  options)!
let nearestHour = calendar.component(.Hour, fromDate: nearestDate)

let now=NSDate（）
让calendar=NSCalendar.currentCalendar（）
让roundDown=calendar.component（.Minute，fromDate:now）<30
let components=NSDateComponents（）
组件。分钟=0
让选项：NSCalendarOptions=roundDown？[.MatchNextTime、.SearchBackwards]：.MatchNextTime
让nearestDate=calendar.nextDateAfterDate（现在，匹配组件：组件，选项：选项）！
设nearestHour=calendar.component（.Hour，fromDate:nearestDate）

目标-C

NSDate *now = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
BOOL roundDown = [calendar component:NSCalendarUnitMinute fromDate: now] < 30 ;
NSDateComponents *components = [[NSDateComponents alloc] init];
components.minute = 0;
NSCalendarOptions options = roundDown ? (NSCalendarMatchNextTime | NSCalendarSearchBackwards) : NSCalendarMatchNextTime;
NSDate *nearestDate = [calendar nextDateAfterDate:now matchingComponents: components options:  options];
NSInteger nearestHour = [calendar component:NSCalendarUnitHour fromDate: nearestDate];

NSDate*now=[NSDate-date]；
NSCalendar*日历=[NSCalendar currentCalendar]；
BOOL roundDown=[日历组件：nsCalendarUnitMinutefromDate:now]<30；
NSDateComponents*components=[[NSDateComponents alloc]init]；
组件。分钟=0；
NSCalendarOptions=roundDown？（NSCalendarMatchNextTime | NSCalendarSearchBackwards）：NSCalendarMatchNextTime；
NSDate*nearestDate=[calendar NextDate Afterdate:现在匹配组件：组件选项：选项]；
NSInteger nearestHour=[日历组件：NSCalendarUnitHour fromDate:nearestDate]；

查看有关

NSDate

的文档。没有

秒

或

小时

等方法。它们必须是Swift代码中的自定义函数。这显示了转换的明确方式[也请参阅此链接][1][1]：我实际上已经看到了该链接。我知道swift代码没有名为hour（）或seconds（）的自定义函数，这就是我为什么感到惊讶的原因。这就是为什么我想要我的问题的答案。@SridharG.K这与这个问题无关。@CodeOxO在

NSDate

上也没有

minuteInSeconds

方法，但您的代码正在调用这样一个方法。它也必须是某种类别方法。解释新版本的原因（swift）比旧版本（xcode/objective c）更易于使用？它们改进了一些东西。

- (int) nearestHour {
    NSDateComponents *components = [[NSCalendar currentCalendar] components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:self];
    NSInteger halfHour = [NSDate minuteInSeconds].intValue * 30;
    NSTimeInterval interval = [self timeIntervalSinceReferenceDate];
    if ([components minutes] < 30) {
        interval -= halfHour;
    }
    else {
        interval += halfHour;
    }
    NSDate *date = [NSDate dateWithTimeIntervalSinceReferenceDate:    interval];
    return [date hour];
}

let now = NSDate()
let calendar = NSCalendar.currentCalendar()
let roundDown = calendar.component(.Minute, fromDate: now) < 30
let components = NSDateComponents()
components.minute = 0
let options : NSCalendarOptions = roundDown ? [.MatchNextTime, .SearchBackwards] : .MatchNextTime
let nearestDate = calendar.nextDateAfterDate(now, matchingComponents: components, options:  options)!
let nearestHour = calendar.component(.Hour, fromDate: nearestDate)

NSDate *now = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
BOOL roundDown = [calendar component:NSCalendarUnitMinute fromDate: now] < 30 ;
NSDateComponents *components = [[NSDateComponents alloc] init];
components.minute = 0;
NSCalendarOptions options = roundDown ? (NSCalendarMatchNextTime | NSCalendarSearchBackwards) : NSCalendarMatchNextTime;
NSDate *nearestDate = [calendar nextDateAfterDate:now matchingComponents: components options:  options];
NSInteger nearestHour = [calendar component:NSCalendarUnitHour fromDate: nearestDate];