您可以使用Apple的原生日历API。在EventKitUI framework中使用EKEventEditViewController，用户将能够在保存事件时指定日历。在Swift 3中：

import UIKit
import EventKit
import EventKitUI

class ViewController: UIViewController {

    let store = EKEventStore()

    func createEvent() {
        // create the event object

        let event = EKEvent(eventStore: store)
        event.title = "Foo"
        event.startDate = ...
        event.endDate = ...

        // prompt user to add event (to whatever calendar they want)

        let controller = EKEventEditViewController()
        controller.event = event
        controller.eventStore = store
        controller.editViewDelegate = self
        present(controller, animated: true)
    }
}

extension ViewController: EKEventEditViewDelegate {

    func eventEditViewController(_ controller: EKEventEditViewController, didCompleteWith action: EKEventEditViewAction) {
        controller.dismiss(animated: true)
    }
}

在Swift 2.3中：

import UIKit
import EventKit
import EventKitUI

class ViewController: UIViewController {

    let store = EKEventStore()

    func createEvent() {
        // create the event object

        let event = EKEvent(eventStore: store)
        event.title = "Foo"
        event.startDate = ...
        event.endDate = ...

        // prompt user to add event (to whatever calendar they want)

        let controller = EKEventEditViewController()
        controller.event = event
        controller.eventStore = store
        controller.editViewDelegate = self
        presentViewController(controller, animated: true, completion: nil)
    }
}

extension ViewController: EKEventEditViewDelegate {

    func eventEditViewController(controller: EKEventEditViewController, didCompleteWithAction action: EKEventEditViewAction) {
        controller.dismissViewControllerAnimated(true, completion: nil)
    }
}

这假设你已经在Info.plist中提供了一个NSCalendarsUsageDescription，你已经有了requested access，等等。

Apple没有本地日历API。
试试这个第三方库Calendar。它看起来和iOS calandar应用程序完全一样，而且它也集成了EKEventStore。我在我的项目中使用过这个库，没有任何问题。

在swift 4.2中完美运行

import UIKit
import EventKit
import EventKitUI

class yourViewController: UIViewController{

    let eventStore = EKEventStore()

    func addEventToCalendar() {

    eventStore.requestAccess( to: EKEntityType.event, completion:{(granted, error) in
        DispatchQueue.main.async {
            if (granted) && (error == nil) {
                let event = EKEvent(eventStore: self.eventStore)
                event.title = self.headerDescription
                event.startDate = self.parse(self.requestDetails.value(forKey: "session_time") as? String ?? "")
                event.endDate = self.parse(self.requestDetails.value(forKey: "session_end_time") as? String ?? "")
                let eventController = EKEventEditViewController()
                eventController.event = event
                eventController.eventStore = self.eventStore
                eventController.editViewDelegate = self
                self.present(eventController, animated: true, completion: nil)

            }
        }

       })
    }

}

现在将出现以下屏幕，您还可以在此处根据要求自定义详细信息：

• //现在在添加事件后关闭视图控制器 *

extension yourViewController: EKEventEditViewDelegate {

    func eventEditViewController(_ controller: EKEventEditViewController, didCompleteWith action: EKEventEditViewAction) {
        controller.dismiss(animated: true, completion: nil)

    }
}

注意：不要忘记将NSCalendarsUsageDescription项添加到信息列表中。