Swift 3 - 从 uiviewcontroller 到不相关类型的 Segue/Cast 总是失败

Question

我正在尝试使用 segue 将 bool 语句从管理 View Controller 的 View Controller 传递到另一个 View Controller ，但我收到“从 uiviewcontroller 转换为不相关类型总是失败”的错误。

主VC

public func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController?{
        guard let viewControllerIndex = theViewControllers.index(of: viewController) else {
            return nil
        }
        let nextIndex = viewControllerIndex + 1

        if(viewControllerIndex == 0){
            let sessionTimerActive: Bool = false
            performSegue(withIdentifier: "sessionActiveBool", sender: sessionTimerActive)

        }

secondVC

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let sessionTrackerBoolClone = segue.destination as? Bool{
    sesssionTrackerActive = sessionTrackerBoolClone
    }
}

然而在行

if let sessionTrackerBoolClone = segue.destination as? Bool{

我遇到了错误。

Answer 1

您需要输入 cast sender 以获得您的 Boolean 值而不是 segue.destination 因为 destination 是 UIViewController< 的类型.

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let sessionTrackerBoolClone = sender as? Bool{
        sesssionTrackerActive = sessionTrackerBoolClone
    }
}

如果您想将此 Bool 值传递给您的下一个 Controller ，请将 destination 类型转换为您的 ViewController 并设置其属性。

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let vc = segue.destination as! ViewController //Your ViewController class
    if let sessionTrackerBoolClone = sender as? Bool{
        vc.sesssionTrackerActive = sessionTrackerBoolClone
    }
}