var placeholderLabel : UILabel!
  textviewDescription.delegate = self
    placeholderLabel = UILabel()
    placeholderLabel.text = "Add a description"

   func textViewDidChange(_ textView: UITextView) {
             placeholderLabel.isHidden = !textviewDescription.text.isEmpty
    }

迅速:

添加你的TextView @IBOutlet:

@IBOutlet weak var txtViewMessage: UITextView!

在viewWillAppear方法中，添加以下内容:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    txtViewMessage.delegate = self    // Give TextViewMessage delegate Method
    
    txtViewMessage.text = "Place Holder Name"
    txtViewMessage.textColor = UIColor.lightGray
}

请添加委托使用扩展(UITextViewDelegate):

// MARK: - UITextViewDelegate
extension ViewController: UITextViewDelegate {

    func textViewDidBeginEditing(_ textView: UITextView) {

        if !txtViewMessage.text!.isEmpty && txtViewMessage.text! == "Place Holder Name" {
            txtViewMessage.text = ""
            txtViewMessage.textColor = UIColor.black
        }
    }

    func textViewDidEndEditing(_ textView: UITextView) {
    
        if txtViewMessage.text.isEmpty {
            txtViewMessage.text = "Place Holder Name"
            txtViewMessage.textColor = UIColor.lightGray
        }
    }
}

斯威夫特

这是一个Swiftui TextView使用UIVIewRepresentable，具有占位符功能和边界颜色

struct TextView: UIViewRepresentable {

@Binding var text: String
var placeholderText: String
var textStyle: UIFont.TextStyle

func makeUIView(context: Context) -> UITextView {
    let textView = UITextView()

    textView.font = UIFont.preferredFont(forTextStyle: textStyle)
    textView.autocapitalizationType = .sentences
    textView.isSelectable = true
    textView.isUserInteractionEnabled = true
    textView.delegate = context.coordinator
    textView.layer.borderWidth = 0.6
    textView.layer.borderColor = UIColor.lightGray.cgColor
    textView.layer.cornerRadius = 10
    textView.text = placeholderText
    textView.textColor = UIColor.lightGray
    return textView
}

func updateUIView(_ uiView: UITextView, context: Context) {
    uiView.text = text
    uiView.font = UIFont.preferredFont(forTextStyle: textStyle)
}

func makeCoordinator() -> Coordinator {
    Coordinator(self)
}
 
class Coordinator: NSObject, UITextViewDelegate {
    var parent: TextView
 
    init(_ parent: TextView) {
        self.parent = parent
    }
 
    func textViewDidChange(_ textView: UITextView) {
        self.parent.text = textView.text
    }
    
    func textViewDidBeginEditing(_ textView: UITextView) {
        if textView.textColor == UIColor.lightGray {
            textView.text = nil
            textView.textColor = UIColor.black
        }
    }
    
    func textViewDidEndEditing(_ textView: UITextView) {
        if textView.text.isEmpty {
            textView.text = self.parent.placeholderText
            textView.textColor = UIColor.lightGray
        }
    }
}

}

然后在你的视图中你可以这样使用它

TextView(text: self.$viewModel.addPostCommentText, placeholderText: "Share your story about this cash", textStyle: .body)
                .padding()
                .frame(height: 150)

var placeholderLabel : UILabel!
  textviewDescription.delegate = self
    placeholderLabel = UILabel()
    placeholderLabel.text = "Add a description"

   func textViewDidChange(_ textView: UITextView) {
             placeholderLabel.isHidden = !textviewDescription.text.isEmpty
    }

可能是UITextView占位符实现的最简单的开箱即用的解决方案，不会遭受:

使用UILabel而不是UITextView，这可能会有不同的表现 切换到和从占位符“UITextView”拷贝，将捕获第一个键入的字符将从主UITextView控件丢失 打乱主UITextView控件的文本内容，将占位符替换为空字符串或第一个键入的字符。边界情况是，如果用户输入占位符文本，一些建议的实现将把它作为一个占位符本身。

斯威夫特5:

import UIKit
import SnapKit
import RxSwift
import RxCocoa

class TextAreaView: UIView {
    let textArea = UITextView()
    let textAreaPlaceholder = UITextView()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonSetup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonSetup()
    }
    
    private func commonSetup() {
        
        addSubview(textAreaPlaceholder)
        addSubview(textArea)
        
        textArea.isScrollEnabled = false
        textArea.delegate = self

        textAreaPlaceholder.isScrollEnabled = false
        textAreaPlaceholder.textColor = UIColor.lightGray
        
        textArea.snp.makeConstraints { make in
            make.top.bottom.leading.trailing.equalToSuperview()
        }

        textAreaPlaceholder.snp.makeConstraints { make in
            make.top.bottom.leading.trailing.equalTo(textArea.snp.top)
        }

        textAreaPlaceholder.text = "Placeholder"
        
        updatePlaceholder()
    }
    
    func updatePlaceholder() {
        if textArea.text.count > 0 {
            textArea.alpha = 1.0
        } else {
            textArea.alpha = 0.0
        }
    }
}

extension TextAreaView: UITextViewDelegate {
    func textViewDidChange(_ textView: UITextView) {
        updatePlaceholder()
    }
}

我不得不调度队列，让我的占位符文本重新出现，一旦编辑完成。

func textViewDidBeginEditing(_ textView: UITextView) {

    if textView.text == "Description" {
        textView.text = nil
    }
}

func textViewDidEndEditing(_ textView: UITextView) {

    if textView.text.isEmpty {
        DispatchQueue.main.async {
            textView.text = "Description"
        }
    }
}