ios - 在 Swift 中创建一个应用程序生命周期对象(不可能被释放)

Question

我想从一个类中创建一个对象。我希望它的生命周期成为应用程序的生命周期。我的意思是我不希望它在应用程序运行时被释放。
我想从中创建实例的类:

extension Post {

    @NSManaged var userId: Int
    @NSManaged var id: Int
    @NSManaged var title: String
    @NSManaged var body: String

}

class Post: NSManagedObject {

// Insert code here to add functionality to your managed object subclass

   override func awakeFromInsert() {
        super.awakeFromInsert()
        title = ""
        userId = 0
        id = 0
        body = ""

    }
}

Answer 1

不能释放指向自身的强指针的对象:

class Permanent {
    private var ref: Permanent?

    init() {
        ref = self
    }

    deinit {
        // This will never be called
        print("Permanent deinit")
    }
}

func test() {
    var a = [Permanent(), Permanent()]
    print(a.count)

    print("free the items")
    a = []
    print("end of test")
}

test()

输出:

2
free the items
end of test

如果您注释掉 ref = self 行:

输出:

2
free the items
Permanent deinit
Permanent deinit
end of test