xcode iOS 中 UIDatePicker 的默认日期
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Default Date for UIDatePicker in iOS
提问by Ali
I am new in iOS development. I have this ViewController in my Storyboard (includes a UIDatePicker and a bar button):
我是 iOS 开发的新手。我的故事板中有这个 ViewController（包括一个 UIDatePicker 和一个条形按钮）：
I followed Data Cellto call my DatePicker. When user click on a button in the page PickerDate pops up with a done bar button on the navigation bar:
我跟着Data Cell调用了我的 DatePicker。当用户单击页面 PickerDate 中的按钮时，导航栏上会弹出一个完成栏按钮：
The problem is it shows just the current date as default. Nothing changes when I set it from Properties:
问题是它只将当前日期显示为default. 当我从属性设置它时没有任何变化：
Do you know how can I fix it? (by setting up the propertiesor programmatically).
你知道我该如何解决吗？（通过setting up the properties或以编程方式）。
回答by Ali
I did it programmatically in this way :
我以这种方式以编程方式做到了：
NSCalendar *calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *components = [[[NSDateComponents alloc] init] autorelease];
[components setYear:1980];
[components setMonth:1];
[components setDay:1];
NSDate *defualtDate = [calendar dateFromComponents:components];
pickerView.date = defualtDate;
But still don't know why it doesn't work by setting up the properties. Any help?
但仍然不知道为什么它不起作用setting up the properties。有什么帮助吗？
回答by King-Wizard
In Swift:
在斯威夫特：
let calendar: NSCalendar = NSCalendar(calendarIdentifier: NSGregorianCalendar)!
calendar.timeZone = NSTimeZone(name: "UTC")!
let components: NSDateComponents = NSDateComponents()
components.year = 1980
components.month = 1
components.day = 1
let defaultDate: NSDate = calendar.dateFromComponents(components)!
self.dateOfBirthUIDatePicker.date = defaultDate
回答by David DelMonte
Great answers above - Here's the Swift3(Feb 17) version:
上面的好答案 - 这是Swift3（2 月 17 日）版本：
let calendar: NSCalendar = NSCalendar(calendarIdentifier: .gregorian)!
calendar.timeZone = NSTimeZone(name: "UTC")! as TimeZone
let components: NSDateComponents = NSDateComponents()
components.year = 1980
components.month = 1
components.day = 1
let defaultDate: NSDate = calendar.date(from: components as DateComponents)! as NSDate
self.datePicker.date = defaultDate as Date
