从一个NSDate获取日期组件，从另一个NSDate获取时间组件的NSDate。

Question

我的应用程序中有两个UIDatePicker控件，一个配置为UIDatePickerModeDate，另一个配置为UIDatePickerModeTime。

我想配置一个NSDate对象，其中包含来自第一个UIDatePicker的日期和第二个UIDatePicker的时间...如何操作？

谢谢， Mark

- Cornelius

Answer 1

假设date1和date2是两个NSDate值。date1包含日期组件，而date2包含时间组件。这是如何将它们组合在一起的：

NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

// Extract date components into components1
NSDateComponents *components1 = [gregorianCalendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit
                                                     fromDate:date1];

// Extract time components into components2
NSDateComponents *components2 = [gregorianCalendar components:NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit 
                                                     fromDate:date2];

// Combine date and time into components3
NSDateComponents *components3 = [[NSDateComponents alloc] init];

[components3 setYear:components1.year];
[components3 setMonth:components1.month];
[components3 setDay:components1.day];    

[components3 setHour:components2.hour];
[components3 setMinute:components2.minute];
[components3 setSecond:components2.second];         

// Generate a new NSDate from components3.
NSDate *combinedDate = [gregorianCalendar dateFromComponents:components3];   

// combinedDate contains both your date and time!

iOS 8.0及以上版本可用

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

// Extract date components into components1
NSDateComponents *components1 = [gregorianCalendar components:(NSCalendarUnit)(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay)
                                                     fromDate:date1];

// Extract time components into components2
NSDateComponents *components2 = [gregorianCalendar components:(NSCalendarUnit)(NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond)
                                                     fromDate:date2];

// Combine date and time into components3
NSDateComponents *components3 = [[NSDateComponents alloc] init];

[components3 setYear:components1.year];
[components3 setMonth:components1.month];
[components3 setDay:components1.day];

[components3 setHour:components2.hour];
[components3 setMinute:components2.minute];
[components3 setSecond:components2.second];

// Generate a new NSDate from components3.
NSDate * combinedDate = [gregorianCalendar dateFromComponents:components3];

// combinedDate contains both your date and time!

- melsam

Answer 2

在Swift中：

let calendar = NSCalendar.currentCalendar()
let date1 = NSDate() // PickerDateMode
let date2 = NSDate() // PickerHourMode

let componentsOne = calendar.components([.Year, .Month, .Day], fromDate: date1)
let componentsTwo = calendar.components([.Hour, .Minute], fromDate: date2)   

let totalComponents = NSDateComponents()
totalComponents.year = componentsOne.year
totalComponents.month = componentsOne.month
totalComponents.day = componentsOne.day
totalComponents.hour = componentsTwo.hour
totalComponents.minute = componentsTwo.minute

let finalDate = calendar.dateFromComponents(totalComponents)

- Nati Lara-Diaz

Answer 3

NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSCalendarUnit unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDate *date = [NSDate date];//datapicker date
NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

NSInteger year = [dateComponents year];
NSInteger month = [dateComponents month];
NSInteger day = [dateComponents day];
NSInteger hour = [dateComponents hour];
NSInteger minute = [dateComponents minute];
NSInteger second = [dateComponents second];

- iKushal

Answer 4

更新至Swift 4和4.1

 func combineDateAndTimeToOneDate() {

    let datefrmter = DateFormatter()
     datefrmter.dateFormat = "dd/MM/yyyy"
    let dateFromString = datefrmter.date(from: lblDate.text!)

    datefrmter.dateFormat = "h:mm a"
    let timeFromString = datefrmter.date(from: lblTime.text!)

    let calendar = NSCalendar.current

    let componentsOne = calendar.dateComponents([.year,.month,.day], from: dateFromString!)
    let componentsTwo = calendar.dateComponents([.hour,.minute,.second,.nanosecond], from: timeFromString!)

    let totalComponents = NSDateComponents()
    totalComponents.year = componentsOne.year!
    totalComponents.month = componentsOne.month!
    totalComponents.day = componentsOne.day!
    totalComponents.hour = componentsTwo.hour!
    totalComponents.minute = componentsTwo.minute!
    totalComponents.second = componentsTwo.second!
    totalComponents.nanosecond = componentsTwo.nanosecond!

    let finalDate = calendar.date(from: totalComponents as DateComponents)
    print(finalDate)

}

希望它有所帮助！

- Harjot Singh

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你不需要使用NSDateComponents并在最后转换为DateComponents，可以直接使用DateComponents，只需将totalComponents从let更改为var即可。 - Fonix