有没有一种方法可以向 UIAlertController 的 NotNow 按钮添加操作，并在用户选择该选项后 24 小时后触发它？

Question

if !force {
    let notNowButton = UIAlertAction(title: "Not Now", style: .cancel) { action in  
        // Not getting what can be written here to make it trigger after 24 hours with the Logic
    }             
    alertController.addAction(notNowButton) 
}

我在 class 中编写了这个函数，我在 AppDelegate class didFinishLaunchingWithOptions launchOptions 函数中调用它。我面临的问题是每次启动应用程序时都会重新出现警报希望它至少在选择此选项时 24 小时内不会出现。

Answer 1

在您的 ViewController 中执行以下操作，请参阅评论中的解释。

class ViewController: UIViewController {

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        displayAlert()
    }


    
    func displayAlert() {
        // get previously stored date from some persistent store (UserDefaults is appropriate)
        let alertDate = UserDefaults.standard.object(forKey: "alertDate")

        // was a date set previously?
        if let alertDate = alertDate as? Date,
            // add the desired time interval to get next possible alert date
            let nextPossibleAlertDate =  Calendar.current.date(byAdding: .day, value: 1, to: alertDate),
            // check if we're past that date
            nextPossibleAlertDate > Date() {
            print("too soon to bother again")
            return
        }

        // let's present the alert
        let alertController = UIAlertController(title: "Do the annoying thing now?", message:
            nil, preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "Not now!", style: .cancel, handler: { action in
            // store the date when this happens
            let date = Date()
            print(date)
            UserDefaults.standard.set(date, forKey: "alertDate" )
        }))
        self.present(alertController, animated: true, completion: nil)
    }
}