无法使用类型的参数列表调用类型为“UIUserNotificationSettings”的初始化程序

Question

我有这个代码使用Swift 1.2，然后我升级，它打破了。在下面的屏幕截图中，我有Swift 1.2和Swift 2版本。

// Register the notification settings.
//swift1.2
//let newNotificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: categoriesForSettings as! Set<NSObject>)

//swift2
let newNotificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: categoriesForSettings as Set<NSObject>)

Answer 1

这是因为初始化程序需要Set<UIUserNotificationCategory>，而不是Set<NSObject>。方法声明如下所示：

public convenience init(forTypes types: UIUserNotificationType, categories: Set<UIUserNotificationCategory>?)

所以将代码更改为：

let notificationTypes = UIUserNotificationType.Sound ...
let categoriesForSettings: Set<UIUserNotificationType> = ...
let newNotificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: categoriesForSettings)