Question

func presentLoggedInScreen() {
    let stroyboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let logginedInVCViewController:LogginedInVCViewController = storyboard.instantiateViewController(withIdentifier: "LogginedInVCViewController" as! LogginedInVCViewController,
    self.present(logginedInVCViewController, animated: true, completion: nil))
}

如何避免此错误？

在其自己的初始值
中使用的变量

Answer 1

试试这个：

func presentLoggedInScreen() {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    if let logginedInVCViewController = storyboard.instantiateViewController(withIdentifier: "LogginedInVCViewController") as? LogginedInVCViewController {
        self.present(logginedInVCViewController, animated: true, completion: nil)
    }
}

编辑：使用可选的绑定和导致错误的是，和额外的）
有时XCode的intellisense无法正常工作，所以首先尝试分析问题:)

Swift - 在其自己的初始值内使用的变量

1 个答案: