Question

我有两个Controller，名称分别为FirstViewController和SecondViewController

FirstViewController是主页，我在这里添加了UITextView。

var secondViewController: SecondViewController!

let textView: UITextView = {
    let textView = UITextView()
    //textView.font = UIFont.systemFont(ofSize: 20)
    textView.isEditable = true
    textView.keyboardDismissMode = .interactive
    textView.allowsEditingTextAttributes = true
    return textView
}()

override func viewDidLoad() {
    super.viewDidLoad()

    secondViewController = SecondViewController()

    setUpLayout() //do something like add the textView to the view
    addKeyboardObserver() //a function which observe the keyboard
}

然后我添加一个按钮以将secondView显示为键盘

@objc func showSecondView() {
    textView.resignFirstResponder()
    textView.inputView = secondViewController.view
    textView.becomeFirstResoonder()
}

然后我定义一个函数来关闭secondView

func closeSecondView() {
    textView.resignFirstResponder()
    textView.inputView = nil
}

在我的SecondViewController

中

var firstViewController: FirstViewController!

override func viewDidLoad() {
    super.viewDidLoad()

    firstViewController = FirstViewController()

    self.view.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 300)
    self.view.backgroundColor = .cyan
}

然后我添加一个按钮以关闭firstViewController的自定义键盘

@objc func closeFontView() {
    print(123)
    firstViewController.closeSecondView()
}

结果是打印“ 123”，然后在closeFontView()处添加一个断点，它被称为。但是没有显示UI的更改。（未关闭键盘）为什么？我该如何解决？

Answer 1

问题出在这里[删除此行]

firstViewController = FirstViewController() // new instance not the real presented first

当您显示第二个（firstViewController里面的东西时，这样连接它

let second = ///
second.first = self
// present second

Answer 2

在您的MyClass中，存储secondViewController的实例。

firstViewController

现在删除var secondViewController: SecondViewController! let textView: UITextView = { let textView = UITextView() //textView.font = UIFont.systemFont(ofSize: 20) textView.isEditable = true textView.keyboardDismissMode = .interactive textView.allowsEditingTextAttributes = true return textView }() override func viewDidLoad() { super.viewDidLoad() secondViewController = SecondViewController() secondViewController.firstViewController = self // <- add this line setUpLayout() //do something like add the textView to the view addKeyboardObserver() //a function which observe the keyboard }中FirstViewController的初始化，因为您需要相同实例，而不需要另一个实例。

SecondViewController

如何从一个ViewController的函数更改属性？

2 个答案: