Swift iOS - 当 TextField、TextView 和背景被点击但丢失事件时删除视图

Question

首先让我说我玩过程序化，但我目前是新手。

我混合了编程视图和故事板对象：

故事板对象：

按钮
文本字段
TextView

程序化视图：

消息标签
viewForMessageLabel

当我按下按钮时，添加了 viewForMessageLabel。在 viewDidLoad 中，我添加了一个点击手势以在点击背景时删除 viewForMessageLabel。我还将相同的点击手势添加到 textField 以删除 viewForMessageLabel（如果存在）。我再次将相同的点击手势添加到 textField 以将其也删除。

如果键盘存在，我会在 viewDidLoad 中向 textField 添加另一个点击手势以关闭它。我发现事情很古怪，我失去了触摸事件。

如果我在触摸背景时按下按钮添加标签，它不会消失。如果我按下 textField，它将关闭它并显示键盘。当我再次按下按钮时 textField 仍然存在时，标签出现，我再次按下 textField 但没有任何反应。当我按 return 隐藏键盘时（我实现了该方法），键盘消失，按下按钮， viewForMessageLabel 出现，现在当我按下 textField 时 viewForMessageLabel 消失. textField 基本上发生了同样的事情。

我要的是

如果 viewForMessageLabel 存在并且我按下背景、textField 或 textView，它应该会消失。
如果 textField 或 textView 的键盘存在并且我按下背景，键盘也应该消失。

我的代码：

class ViewController: UIViewController, UITextFieldDelegate, UITextViewDelegate {

    //MARK:- Outlets
    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var button: UIButton!

    let messagelabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "Pizza Pizza Pizza Pizza Pizza"
        label.font = UIFont(name: "Helvetica-Regular", size: 17)
        label.sizeToFit()
        label.numberOfLines = 0
        label.textAlignment = .center
        label.textColor = UIColor.white
        label.backgroundColor = UIColor.clear
        return label
    }()

    let viewForMessageLabel: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor.red
        return view
    }()

    //View Controller Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()

        textField.delegate = self
        textView.delegate = self

        // 0. hide viewForMessageLabel is background is tapped
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(removeViewForMessageLabel))
        view.addGestureRecognizer(tapGesture)

        // 1. hide viewForMessageLabel if textView is tapped
        textView.addGestureRecognizer(tapGesture)

        // 2. hide keyboard if background if tapped
        let hideKeyboard = UITapGestureRecognizer(target: self, action: #selector(hideKeyboardWhenBackGroundTapped))
        view.addGestureRecognizer(hideKeyboard)

        // 3. hide keyboard if textView is tapped
        textView.addGestureRecognizer(hideKeyboard)

        // 4. hide viewForMessageLabel for textField if background is tapped
        textField.addTarget(self, action: #selector(removeViewForMessageLabel), for: .editingDidBegin)

    }

    //MARK:- Button
    @IBAction func buttonPressed(_ sender: UIButton) {
        view.addSubview(viewForMessageLabel)
        setViewForMessageLabelAnchors()
        setMessageLabelAnchors()
    }

    //MARK:- Functions
    func setViewForMessageLabelAnchors(){
        viewForMessageLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 44).isActive = true
        viewForMessageLabel.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
        viewForMessageLabel.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
        viewForMessageLabel.addSubview(messagelabel)
    }

    func setMessageLabelAnchors(){
        messagelabel.topAnchor.constraint(equalTo: viewForMessageLabel.topAnchor, constant: 0).isActive = true
        messagelabel.widthAnchor.constraint(equalTo: viewForMessageLabel.widthAnchor).isActive = true
        viewForMessageLabel.bottomAnchor.constraint(equalTo: messagelabel.bottomAnchor, constant: 0).isActive = true
    }

    func removeViewForMessageLabel(){
        viewForMessageLabel.removeFromSuperview()
    }

    func hideKeyboardWhenBackGroundTapped(){
        textField.resignFirstResponder()
    }

    //MARK:- TextField Delegate
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        view.endEditing(true)
        return true
    }

    func textViewDidBeginEditing(_ textView: UITextView) {
        removeViewForMessageLabel()
    }

    //MARK:- TextView Delegate
    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        if(text == "\n") {
            textView.resignFirstResponder()
            return false
        }
        return true
    }
}

Answer 1

If the textField's or textView's keyboard is present and I press the background the keyboard should disappear also.

您将其呈现为以当前是否显示键盘为条件，但您的代码并未反映（也不应该）。您可以根据需要多次调用 resignFirstResponder 并且不会发生任何不好的事情。您还可以在已删除的视图上调用 removeFromSuperview（请参阅 here）。

因此我认为您可以只将一个动作附加到单击手势识别器：

var tapGesture: UITapGestureRecognizer?

override func viewDidLoad() {
    super.viewDidLoad()

    textField.delegate = self
    textView.delegate = self

    // 0. hide viewForMessageLabel is background is tapped
    tapGesture = UITapGestureRecognizer(target: self, action: #selector(removeLabelAndHideKeyboard))
    view.addGestureRecognizer(tapGesture)

    // 1. hide viewForMessageLabel if textView is tapped
    textView.addGestureRecognizer(tapGesture)
}

func removeLabelAndHideKeyboard() {
    viewForMessageLabel.removeFromSuperview()
    textField.resignFirstResponder()
}

Answer 2

这并不能完全回答问题，但我找到了解决方法。如果我使用@Toddg 建议的方法：

func removeLabelAndHideKeyboard() {
    viewForMessageLabel.removeFromSuperview()
    textField.resignFirstResponder()
}

它将退出 textField 添加到功能中，这非常有帮助。

我还在 viewDidLoad 中添加了：

textField.addTarget(self, action: #selector(removeViewForMessageLabel), for: .touchDown)

关键是使用 .touchDown 而不是 .editingDidBegin。这样我就可以在 textField 和 textView 之间来回切换，键盘将响应两者。我不得不再添加 1 个东西 - 一个 toolBar 到 textView 的键盘，上面有完成按钮以关闭 textView:

    func addDoneButtonOnKeyboard(){
        let toolBar = UIToolbar()
        toolBar.sizeToFit()
        doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(dismissKeyboard))
        toolBar.setItems([doneButton!], animated: true)
        textView.inputAccessoryView = toolBar
    }

    @objc func dismissTextViewKeyboard(){
        view.endEditing(true)
    }

这样当 textView 出现时我可以关闭它。

在所有情况下，如果我按下 textField、background 或 textView 并且存在 viewForMessageLabel，它就会消失。

如果 textField 是第一响应者并且它的键盘存在并且我按下背景它就会消失。

除了其他所有内容之外，我还没有弄清楚如何在触摸背景时也关闭 textView，所以我在工具栏上实现了一个完成按钮。如果我按下它并且 textView 的键盘存在，当它调用我添加的 dismissTextViewKeyboard() 函数时将被关闭。两者都在底部，其他所有内容都在 viewDidLoad 中。

如果有人有更好的答案，我会投票给它。

class ViewController: UIViewController, UITextFieldDelegate, UITextViewDelegate {


    //MARK:- Outlets
    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var button: UIButton!

    let messagelabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "Pizza Pizza Pizza Pizza Pizza"
        label.font = UIFont(name: "Helvetica-Regular", size: 17)
        label.sizeToFit()
        label.numberOfLines = 0
        label.textAlignment = .center
        label.textColor = UIColor.white
        label.backgroundColor = UIColor.clear
        return label
    }()

    let viewForMessageLabel: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor.red
        return view
    }()

    fileprivate var doneButton: UIBarButtonItem?

    //View Controller Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()

        textField.delegate = self
        textView.delegate = self

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(removeViewForMessageLabel))
        view.addGestureRecognizer(tapGesture)

        textField.addTarget(self, action: #selector(removeViewForMessageLabel), for: .touchDown)

        addDoneButtonOnKeyboard()
    }

    //MARK:- Button
    @IBAction func buttonPressed(_ sender: UIButton) {
        //removeMessage()
        view.addSubview(viewForMessageLabel)
        setBackgroundAnchors()
        setMessageAndLabelAnchors()
    }

    //MARK:- Functions
    func setBackgroundAnchors(){
        viewForMessageLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 44).isActive = true
        viewForMessageLabel.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
        viewForMessageLabel.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
        viewForMessageLabel.addSubview(messagelabel)
    }

    func setMessageAndLabelAnchors(){

        messagelabel.topAnchor.constraint(equalTo: viewForMessageLabel.topAnchor, constant: 0).isActive = true
        messagelabel.widthAnchor.constraint(equalTo: viewForMessageLabel.widthAnchor).isActive = true
        viewForMessageLabel.bottomAnchor.constraint(equalTo: messagelabel.bottomAnchor, constant: 0).isActive = true
    }

    func removeViewForMessageLabel(){
        viewForMessageLabel.removeFromSuperview()
        textField.resignFirstResponder()
    }

    //MARK:- TextField Delegate
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        view.endEditing(true)
        return true
    }

    func textViewDidBeginEditing(_ textView: UITextView) {
        removeViewForMessageLabel()
    }

    //MARK:- TextView Delegate
    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        if(text == "\n") {
            textView.resignFirstResponder()
            return false
        }
        return true
    }

    //MARK:- Additional Functions
    //add a done button to the keyboard when the textView is first responder
    fileprivate func addDoneButtonOnKeyboard(){
        let toolBar = UIToolbar()
        toolBar.sizeToFit()
        doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(dismissTextViewKeyboard))
        toolBar.setItems([doneButton!], animated: true)
        textView.inputAccessoryView = toolBar
    }

    //dismiss the keyboard when the Done button is tapped
    @objc func dismissTextViewKeyboard(){
        view.endEditing(true)
    }
}

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