Question

我正在尝试保存我所拥有的某些UIDatePickers的选定时间。我的日期选择器名为datePicker1。它目前设置为小时和分钟我有一个“保存”按钮，我想保存datePickers时间（小时和分钟），并能够稍后回拨这些时间。我目前正在使用NSUserDefaults，但如果有更好的方法，请告诉我。（日期与它无关，我正在创建一个应用程序，每天都会给用户一个通知，所以我关心的是小时和分钟计数）。任何帮助将不胜感激。

Answer 1

如果您想将小时和分钟保存为字符串，这可能会给您一些想法。此实现涉及到单个UIDatePicker的插座和附加到“保存”按钮的操作：

class ViewController: UIViewController {

@IBOutlet weak var datePicker: UIDatePicker!

@IBAction func save(sender: UIButton) {

    let dateOnPicker = datePicker.date //capture the date shown on the picker

    let dateFormatter = NSDateFormatter() //create a date formatter

    //if you want to convert time to string like "9:07 PM":
    dateFormatter.timeStyle = NSDateFormatterStyle.ShortStyle //check out docs for NSDateFormatterStyle to see other styles
    let timeAsString = dateFormatter.stringFromDate(dateOnPicker)
    print(timeAsString) //ex. prints 3:04 AM as "3:04 AM" and 11:37 PM as "11:37 PM"

    //if you want to convert time to string like "0627" (military time):
    dateFormatter.dateFormat = "HHmm" //could also store as HH:mm if you want a colon in the string 
    let timeAsStringMilitaryTime = dateFormatter.stringFromDate(dateOnPicker)
    print(timeAsStringMilitaryTime) //in miliatary time: ex. prints 3:04AM as "0304" and 11:37 PM as "2337"

    //there are other options, but these are two that you might find useful!

    //you could then save either version (whichever you end up using) to NSUserDefaults as a string; i went with the military time version since i think it's easier to parse, but just personal preference:
    NSUserDefaults.standardUserDefaults().setObject(timeAsStringMilitaryTime, forKey: "SavedTime")
}

override func viewDidLoad() {
    super.viewDidLoad()

    //when you start up (or whenever you want to retrieve the saved time), you could check to see if you have a time saved, and if so, parse it into hours and minutes (assuming you are saving the military time version):

    if let savedTime = NSUserDefaults.standardUserDefaults().objectForKey("SavedTime") as? String {

        //the "HHmm" military time format will ALWAYS be 4 digits long, and the first two characters represent the hours and the second two characters represent the minutes

        let hoursRange = savedTime.startIndex...savedTime.startIndex.advancedBy(1)  //refers to the first two digits of 4-digit time)
        let hours =  savedTime[hoursRange]

        let minutesRange = savedTime.startIndex.advancedBy(2)...savedTime.endIndex.predecessor()  //refers to the last two digits of 4-digit time)
        let minutes = savedTime[minutesRange]

        print(hours)
        print(minutes)
    }
}

希望这有用！

麦克

Answer 2

如果您使用的是UIDatePickerView :(在故事板中设置为Time）以下函数将保存/加载时间作为NSDate，并且由于您的UIDatePickerView设置为Time，因此只显示小时/分钟

定义一个变量＆＃34; time＆＃34;您保存所选日期的地方

var date :NSDate?

使用此功能将数据保存到变量

func save(){
    date = datePicker1.date
}

使用此功能从变量

加载数据

func load(){
    if date != nil {
        datePicker1.setDate(date!, animated: true)
    }
}

UIDatePicker快速节省时间

2 个答案: