swift - Xcode "po"命令保留值

Question

我一直在调试我的代码，发现我的管理器被取消初始化(这是我的错误的原因 - 没有调用委托(delegate)方法)。

奇怪的是，在调试过程中，我在设置管理器的委托(delegate)(弱)后使用了“po”命令，它阻止了它被取消初始化(委托(delegate)方法被调用)。

这是为什么呢？这是正确的行为吗？

Xcode 8.3、swift 3.1

编辑:

//a tap starts everything :)

    @IBAction func shareButtonPressed(_ sender: Any) {
        let requestManager = FacebookPostRouteRequest() //bug fixed by changing to instance variable
        requestManager.delegate = self
        requestManager.showShareBadgeDialog(self.badge!, onViewController: self)
    }

//in FacebookPostRouteRequest
        final weak var delegate: FacebookPostRouteRequestDelegate?

        func showShareBadgeDialog(_ badge: Badge, onViewController viewController: UIViewController) {
            let dialog = self.initDialog(onViewController: viewController)
            guard let imageURL = badge.imageURL else {
                self.delegate?.facebookPostRouteRequest(self, didCompleteWithResult: false)
                return
            }

            dialog.shareContent = self.generateImageShareContent(imageURL)
            self.show(dialog)
        }

 private func show(_ dialog: FBSDKShareDialog) {
        OperationQueue.main.addOperation {
            dialog.delegate = self //when printed out dialog.delegate delegate methods were called! Deinit of FacebookPostRouteRequest is not called.
            let showResult = dialog.show() 
            ...
            }
        }

extension FacebookPostRouteRequest: FBSDKSharingDelegate {
    func sharer(_ sharer: FBSDKSharing!, didCompleteWithResults results: [AnyHashable : Any]!) {
        ...
    }
        //other delegate methods implemented as well

}

Answer 1

你的问题在这里:

@IBAction func shareButtonPressed(_ sender: Any) {
    let requestManager = FacebookPostRouteRequest()
    requestManager.delegate = self
    requestManager.showShareBadgeDialog(self.badge!, onViewController: self)
}

在最后一行之后，requestManager 对象将被释放，因为它不再被引用并且不会调用任何委托(delegate)方法。

使requestManager成为一个实例变量:

let requestManager = FacebookPostRouteRequest()
@IBAction func shareButtonPressed(_ sender: Any) {
    requestManager.delegate = self
    requestManager.showShareBadgeDialog(self.badge!, onViewController: self)
}

您的调试器问题可能是停止主线程的竞争条件。