iOS - 切换UITextfields时不触发键盘通知

Question

通知发生了奇怪的行为。每当我将一个UITextfield切换到另一个时，我的通知就会正常启动。但最近我注意到，当他们从一个UITextField切换到另一个textFieldDidBeginEditing时，他们并没有被解雇，但是当键盘被隐藏时正常射击。 Apple改变了这种逻辑吗？

我需要将该字段滚动到可见状态，并且由于观察者在切换时没有现在开火，因此字段不会显示为可见矩形。

我已经通过在UITextfield上发布通知创建了一个替代方案，但是如果有可能的话我想回到过去。

Answer 1

我找到了问题的真正原因。如果Why is UIKeyboardWillShowNotification called every time another TextField is selected?没有附件视图，则在切换时不会调用键盘通知;如果是附件视图，则每次都会调用它们（UIButton）

在我的情况下，我在每个字段上都有附件视图，但在添加附件视图时，我正在为所有字段添加相同的视图，这才是真正的问题。我需要将不同的UIView实例分配给不同的字段。我一做到这一点，我的问题就消失了。

Answer 2

我遇到了完全相同的问题，我通过创建一个带有新按钮的accessoryView来处理它，该按钮是我实际按钮的重复。所以基本上，考虑你有一个UIViewController坚持在UITextField的底部，你有2 UIButton，当交换切换时，不能感觉

@IBOutlet weak var signInBtn: UIButton!
@IBOutlet weak var passwordTextField: UITextField!
@IBOutlet weak var emailTextField: UITextField!

var accessoryViewKeyboard:UIView?
var btnAccessory:UIButton?


override func viewDidLoad() {
    super.viewDidLoad()

    passwordTextField.delegate = self
    emailTextField.delegate = self

    accessoryViewKeyboard = UIView(frame: signInBtn.frame)

    //Inputting the "accessoryViewKeyboard" here as the "inputAccessoryView" is of 
    //utmost importance to help the "signInBtn" to show up on tap of different "UITextFields"
    emailTextField.inputAccessoryView = accessoryViewKeyboard
    passwordTextField.inputAccessoryView = accessoryViewKeyboard

    setupBtnWithKeyboard()
}

func setupBtnWithKeyboard() {
    btnAccessory = UIButton(frame: CGRect(x: signInBtn.frame.origin.x, y: signInBtn.frame.origin.y, width: self.view.frame.size.width, height: signInBtn.frame.size.height))
    accessoryViewKeyboard?.addSubview(btnAccessory!)
    btnAccessory?.translatesAutoresizingMaskIntoConstraints = false
    btnAccessory?.frame = CGRect(x: (accessoryViewKeyboard?.frame.origin.x)!,
                                 y: (accessoryViewKeyboard?.frame.origin.y)!,
                                 width: self.view.frame.size.width,
                                 height: (accessoryViewKeyboard?.frame.size.height)!)

    btnAccessory?.backgroundColor = UIColor(red: 31/255, green: 33/255, blue: 108/255, alpha: 1)
    btnAccessory?.setTitle("Sign In", for: .normal)
    btnAccessory?.titleLabel?.font = .systemFont(ofSize: 22)
    btnAccessory?.titleLabel?.textColor = UIColor.white
    btnAccessory?.titleLabel?.textAlignment = .center
    btnAccessory?.isEnabled = true
    btnAccessory?.addTarget(self, action: #selector(SignIn.signInBtnPressed), for: .touchUpInside)

    NSLayoutConstraint.activate([
        btnAccessory!.leadingAnchor.constraint(equalTo:
            accessoryViewKeyboard!.leadingAnchor, constant: 0),
        btnAccessory!.centerYAnchor.constraint(equalTo:
            accessoryViewKeyboard!.centerYAnchor),
        btnAccessory!.trailingAnchor.constraint(equalTo:
            accessoryViewKeyboard!.trailingAnchor, constant: 0),
        btnAccessory!.heightAnchor.constraint(equalToConstant: signInBtn.frame.size.height),
        ])
}

曾经移动到别处，但仍然卡在键盘上。以下代码解释了如何解决此问题：

UIButton

而且你已经完成了。这将使UITextField始终出现在键盘上。重要的是无论你介绍多少accessoryViewKeyboard实例，总是输入inputAccessoryView作为其qazxswpoi。