macos - Swift NotificationCenter无法解开Optional.None

我在编写简单的程序
我想在mac os x上显示通知
这是我的密码

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)
}

代码生成成功，但在停止运行代码时

fatal error: Can't unwrap Optional.None

var notificationcenter:NSUserNotificationCenter = NSUserNotificationCenter.defaultUserNotificationCenter()

我能做什么

最佳答案

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

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