swift - 类似于闭包的弱var之类的东西

Question

我该如何修复这个代码，不阻止对象

class EIUIBarButtonItem: UIBarButtonItem {
    typealias HandleClosure = (UIBarButtonItem) -> Void
    fileprivate var handle: HandleClosure?
    init(image: UIImage?, style: UIBarButtonItemStyle, handle: HandleClosure? = nil) {
        self.handle = handle
        super.init()
        self.image = image
        self.style = style
        self.target = self
        self.action = #selector(buttonAction(_:))
    }
    // ...OtherCode...        
    @objc func buttonAction(_ sender: UIBarButtonItem) {
        handle?(sender)
    }
}

如果我将此按钮创建为

EIUIBarButtonItem(image: myUIImage, style: .plain, handle: controller.buttonAction)

我阻止了对象 Controller 。我怎样才能做一些这样的事情？我的句柄需要弱变量

   weak var handle: HandleClosure?

或者类似的东西(@unowned)

   EIUIBarButtonItem(image: myUIImage, style: .plain, handle: @unowned controller.buttonAction)

Answer 1

不要直接传递对 Controller 方法的引用，而是将其包装在闭包中。

... handle: { [weak controller] button in controller?.buttonAction(button) })