将日期转换为DateComponents函数来安排Swift中的本地通知3

Question

我正在尝试设置一个函数，该函数将在接下来的n天内接收一个整数并计划本地通知。我收到一个错误，我无法将Date类型转换为DateComponents。我一直无法弄清楚如何转换它。我发现了一些其他类似的问题here和here，但我还没有能够适应这些答案在Swift 3上工作。

如何将Date转换为DateComponents？有没有更好的方式来安排通知？

在此先感谢您的帮助:)

有错误的路线，“无法将类型的价值‘日期？’预期参数类型 'DateComponents'“：

let trigger = UNCalendarNotificationTrigger(dateMatching: fireDateOfNotification, repeats: false) 

全功能：

func scheduleNotification(day:Int) {  
    let date = Date() 
    let calendar = Calendar.current 
    var components = calendar.dateComponents([.day, .month, .year], from: date as Date) 
    let tempDate = calendar.date(from: components) 
    var comps = DateComponents() 

    //set future day variable 
    comps.day = day 

    //set date to fire alert 
    let fireDateOfNotification = calendar.date(byAdding: comps as DateComponents, to: tempDate!) 

    let trigger = UNCalendarNotificationTrigger(dateMatching: fireDateOfNotification, repeats: false) //THIS LINE CAUSES ERROR 

    let content = UNMutableNotificationContent() 
    content.title = "New Alert Title" 
    content.body = "Body of alert" 
    content.sound = UNNotificationSound.default() 

    let request = UNNotificationRequest(identifier: "alertNotification", content: content, trigger: trigger) 

    UNUserNotificationCenter.current().add(request) {(error) in 
     if let error = error { 
      print("Uh oh! We had an error: \(error)") 
     } 
    } 
} 

Answer 1

我认为错误是明显的，因为它可以。 UNCalendarNotificationTrigger的意思是灵活的，以便您可以指定“下周五触发触发器”。所有你需要的转换下一次触发日到DateComponents：

let n = 7 
let nextTriggerDate = Calendar.current.date(byAdding: .day, value: n, to: Date())! 
let comps = Calendar.current.dateComponents([.year, .month, .day], from: nextTriggerDate) 

let trigger = UNCalendarNotificationTrigger(dateMatching: comps, repeats: false) 
print(trigger.nextTriggerDate())