Question

我有一个答案数组和一个按钮数组。当我单击特定按钮时，在sender.tag的帮助下，我进行了索引更改。我还需要在override func prepare(for segue: UIStoryboardSegue, sender: Any?)中进行操作，以便答案由索引设置，结果将转到另一个屏幕。

当我尝试创建sender.tag时出现错误

“任何类型”的值？没有成员“标签”

@IBAction func answerPressed(_ sender: UIButton) {

    let index = sender.tag
    let currentAnswer = currentQuestions?.answers[index]

    if currentAnswer!.type != .next {
        performSegue(withIdentifier: "segue", sender: sender)
    } else {
        currentQuestions = currentAnswer!.nextQuestion
        updateTittles(currentQuestions)
    }
}


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

    let index = sender.tag
    let currentType = currentQuestions?.answers[index].type

    let resultViewController = segue.destination as! ResultViewController
    resultViewController.type = currentType

}

Answer 1

在这种情况下，用于准备segue功能的sender不一定是UIButton，它是发起segue的任何因素。您可以尝试将其转换为一个按钮，以查看它是否为按钮：

if let button = sender as? UIButton {
    index = button.tag
}

您还可以在answerPressed函数中执行操作，而不是执行segue，您可以在此处实例化ResultViewController，然后将其实例化。因为当您使用此功能时，您知道发件人是UIButton，并且应该有标签。

Answer 2

任何任何都可以是sender的类型，参数声明为Any

在成功执行后，首先检查segue的identifier，将sender参数下调为UIButton

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    guard segue.identifier == "segue" else { return }
    let button = sender as! UIButton
    let currentType = currentQuestions?.answers[button.tag].type
    let resultViewController = segue.destination as! ResultViewController
    resultViewController.type = currentType

}

但是不必传递整个UIButton实例，标记/索引就足够了，或者-更有效的是-传递currentAnswer.type

@IBAction func answerPressed(_ sender: UIButton) {

    let index = sender.tag
    let currentAnswer = currentQuestions?.answers[index]

    if currentAnswer!.type != .next {
        performSegue(withIdentifier: "segue", sender: index)
    } else {
        currentQuestions = currentAnswer!.nextQuestion
        updateTittles(currentQuestions)
    }
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    guard segue.identifier == "segue" else { return }
    let index = sender as! Int
    let currentType = currentQuestions?.answers[index].type
    let resultViewController = segue.destination as! ResultViewController
    resultViewController.type = currentType
}

Answer 3

“任何类型”的值？没有成员“标签”

表示Mono<Long> clock = Mono.defer(() -> Mono.just(System.currentTimeMillis())); //time == t0 Thread.sleep(10_000); //time == t10 clock.block(); //invoked currentTimeMillis() here and returns t10 Thread.sleep(7_000); //time == t17 clock.block(); //invoke currentTimeMillis() once again here and returns t17对象实际上没有Any属性。您知道您的tag是sender，所以为什么不将UIButton中的sender转换成prepareForSegue对象呢？？

UIButton

如何在另一个函数中创建sender.tag UIButton？

3 个答案: