macos - Swift NotificationCenter 无法解包 Optional.None

Question

我正在编写简单的程序 我想在 mac os x 上显示通知

这是我的代码

import Foundation
import Cocoa

var notification:NSUserNotification = NSUserNotification()
notification.title = "TEST"
notification.subtitle = "TTTT"


var notificationcenter:NSUserNotificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter()
if(notificationcenter != nil) {
    notificationcenter.scheduleNotification(notification)
}

该代码构建成功但停止运行代码时

fatal error: Can't unwrap Optional.None

var notificationcenter:NSUserNotificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter()

我能做什么

Answer 1

你得到这个是因为你尝试 unwrap optional，它可以是 nil，你可以这样做:

if let notificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter() {
    notificationcenter.scheduleNotification(notification)
}