objective-c 如何向 NSDate 添加小时数？
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How to add hours to an NSDate?
提问by Rahul Vyas
I have a date converted to double value and saved in database. Now, I want to compare if currentDate > myDataBaseDate + 8hours i.e., I want to get 8 hours added to myDataBaseDate. I'm converting date into double values. So how do I get 8 hours later time from my database saved date. How do I compare
我有一个日期转换为双精度值并保存在数据库中。现在，我想比较currentDate > myDataBaseDate + 8小时，即，我想将 8 小时添加到 myDataBaseDate。我正在将日期转换为双精度值。那么如何从我的数据库保存日期中获得 8 小时后的时间。我如何比较
if (currentDateTime > DateFromdatabaseValue + DateByAdding8HoursInDataBase)
回答by Tom Jefferys
I'm not entirely sure what you are trying to do, but you can create an NSDate object by adding time in seconds on to another NSDate using:
我不完全确定您要做什么，但是您可以通过使用以下方法将时间（以秒为单位）添加到另一个 NSDate 来创建 NSDate 对象：
- (id)dateByAddingTimeInterval:(NSTimeInterval)seconds
- (id)dateByAddingTimeInterval:(NSTimeInterval)seconds
// eg. to add 8 hours to current time:
// 例如。将 8 小时添加到当前时间：
NSDate *mydate = [NSDate date];
NSTimeInterval secondsInEightHours = 8 * 60 * 60;
NSDate *dateEightHoursAhead = [mydate dateByAddingTimeInterval:secondsInEightHours];
回答by Ben Packard
Since iOS 8 there is the more convenient dateByAddingUnit:
由于 iOS 8 有更方便的dateByAddingUnit：
//add 8 hours
let calendar = NSCalendar.autoupdatingCurrentCalendar()
newDate = calendar.dateByAddingUnit(.CalendarUnitHour, value: 8, toDate: originalDate, options: nil)
回答by TechSeeko
You can simply use:
您可以简单地使用：
NSDate *incrementedDate = [NSDate dateWithTimeInterval:numberOfSeconds sinceDate:[NSDate date]];
回答by Pascal
You can simply add 8 * 3600 to your database value (assuming that your converted double value represents seconds).
您可以简单地将 8 * 3600 添加到您的数据库值（假设您转换的双精度值代表秒）。
回答by Venu Gopal Tewari
NSDate *startdate = datePicker.date;
NSDate *startdate = datePicker.date;
NSTimeInterval secondsInOneHours = 1 * 60 * 60;
NSDate *dateOneHoursAhead = [startdate dateByAddingTimeInterval:secondsInOneHours];
[dateformate setDateFormat:@"d-MMM-yy HH:mm:ss"];
strDate = [dateformate stringFromDate:dateOneHoursAhead];
回答by SwiftDeveloper
Swift 3.XSimple usage
Swift 3.X简单使用
let calendar = NSCalendar.autoupdatingCurrent
let newDate = calendar.date(byAdding: .hour, value: 8, to: Date())
