同一类中的两个“performSegue”到不同的视图控制器

Question

我正在尝试使用两个不同的按钮访问两个不同的 VC。有了'newGeneratedListBtn，我只想去vc1。使用“newEmptyList”按钮，我想使用一个可以工作的布尔值转到 vc3。但是，当我单击第一个按钮 'newGeneratedListBtn' 转到 vc1 时，出现错误：“无法将 'AppName.vc1' 类型的值转换为 'AppName.vc3'。

似乎当我单击按钮到 vc1 时，它会尝试发送与我想发送到 vc3 相同的值。我该如何解决这个问题？

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


let value = true

//Button to VC1
@IBAction func newGeneratedListBtn(_ sender: UIButton) {
    performSegue(withIdentifier: "unwindSegueToVC1", sender: self)
}

//Value to send to VC2
override func prepare (for segue: UIStoryboardSegue, sender: Any!) {

        let vc = segue.destination as! ListView
        vc.newEmptyListValue = value
}

//Button to VC2
@IBAction func newEmptyList(_ sender: UIButton) {

    performSegue(withIdentifier: "valueSender2", sender: self)
}

}

Answer 1

您需要转换为特定标识符

override func prepare (for segue: UIStoryboardSegue, sender: Any!) {
    super.prepare(for:segue,sender:sender)
    if segue.identifier == "valueSender2" {
       let vc = segue.destination as! ListView
       vc.newEmptyListValue = value 
    }
    else {
       // it's unwindSegueToVC1
    }
}

两者兼而有之

performSegue(withIdentifier: "unwindSegueToVC1", sender: self) 
performSegue(withIdentifier: "valueSender2", sender: self)

致电prepare

Answer 2

问题是prepare(for:sender:)只有一个实现，像这样：

override func prepare (for segue: UIStoryboardSegue, sender: Any!) {

        let vc = segue.destination as! ListView
        vc.newEmptyListValue = value
}

两个 你的 segues 都通过这一种方法。您必须使用开关或其他条件来确定哪个这是segue，并发送适合该segue的信息。