func setPlaceholder(){ var placeholderLabel = UILabel() placeholderLabel.text = "Describe your need..." placeholderLabel.font = UIFont.init(name: "Lato-Regular", size: 15.0) ?? UIFont.boldSystemFont(ofSize: 14.0) placeholderLabel.sizeToFit() descriptionTextView.addSubview(placeholderLabel) placeholderLabel.frame.origin = CGPoint(x: 5, y: (descriptionTextView.font?.pointSize)! / 2) placeholderLabel.textColor = UIColor.lightGray placeholderLabel.isHidden = !descriptionTextView.text.isEmpty } //Delegate Method. func textViewDidChange(_ textView: UITextView) { placeholderLabel.isHidden = !textView.text.isEmpty }

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)

还有一个解决方案(Swift 3):

import UIKit

protocol PlaceholderTextViewDelegate {
    func placeholderTextViewDidChangeText(_ text:String)
    func placeholderTextViewDidEndEditing(_ text:String)
}

final class PlaceholderTextView: UITextView {

    var notifier:PlaceholderTextViewDelegate?

    var placeholder: String? {
        didSet {
            placeholderLabel?.text = placeholder
        }
    }
    var placeholderColor = UIColor.lightGray
    var placeholderFont = UIFont.appMainFontForSize(14.0) {
        didSet {
            placeholderLabel?.font = placeholderFont
        }
    }

    fileprivate var placeholderLabel: UILabel?

    // MARK: - LifeCycle

    init() {
        super.init(frame: CGRect.zero, textContainer: nil)
        awakeFromNib()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func awakeFromNib() {
        super.awakeFromNib()

        self.delegate = self
        NotificationCenter.default.addObserver(self, selector: #selector(PlaceholderTextView.textDidChangeHandler(notification:)), name: .UITextViewTextDidChange, object: nil)

        placeholderLabel = UILabel()
        placeholderLabel?.textColor = placeholderColor
        placeholderLabel?.text = placeholder
        placeholderLabel?.textAlignment = .left
        placeholderLabel?.numberOfLines = 0
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        placeholderLabel?.font = placeholderFont

        var height:CGFloat = placeholderFont.lineHeight
        if let data = placeholderLabel?.text {

            let expectedDefaultWidth:CGFloat = bounds.size.width
            let fontSize:CGFloat = placeholderFont.pointSize

            let textView = UITextView()
            textView.text = data
            textView.font = UIFont.appMainFontForSize(fontSize)
            let sizeForTextView = textView.sizeThatFits(CGSize(width: expectedDefaultWidth,
                                                               height: CGFloat.greatestFiniteMagnitude))
            let expectedTextViewHeight = sizeForTextView.height

            if expectedTextViewHeight > height {
                height = expectedTextViewHeight
            }
        }

        placeholderLabel?.frame = CGRect(x: 5, y: 0, width: bounds.size.width - 16, height: height)

        if text.isEmpty {
            addSubview(placeholderLabel!)
            bringSubview(toFront: placeholderLabel!)
        } else {
            placeholderLabel?.removeFromSuperview()
        }
    }

    func textDidChangeHandler(notification: Notification) {
        layoutSubviews()
    }

}

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

    func textViewDidChange(_ textView: UITextView) {
        notifier?.placeholderTextViewDidChangeText(textView.text)
    }

    func textViewDidEndEditing(_ textView: UITextView) {
        notifier?.placeholderTextViewDidEndEditing(textView.text)
    }
}

结果

斯威夫特5.2

独立的类

如果你想要一个类，你可以在任何地方使用，因为它是自包含的

import UIKit
class PlaceHolderTextView:UITextView, UITextViewDelegate{
var placeholderText = "placeholderText"

override func willMove(toSuperview newSuperview: UIView?) {
    textColor = .lightText
    delegate = self
}

func textViewDidBeginEditing(_ textView: UITextView) {
    if textView.text == placeholderText{
        placeholderText = textView.text
        textView.text = ""
        textView.textColor = .darkText
    }
}

func textViewDidEndEditing(_ textView: UITextView) {
    if textView.text == ""{
        textView.text = placeholderText
        textColor = .lightText
    }
}    
}

这里的关键是willMove(toSuperView:)函数，因为它允许你在添加到另一个视图的层次结构之前设置视图(类似于ViewControllers中的viewDidLoad/viewWillAppear)

没有这样的属性在ios添加占位符直接在TextView，而你可以添加一个标签和显示/隐藏在TextView的变化。SWIFT 2.0，确保实现textviewdelegate

func textViewDidChange(TextView: UITextView)
{

 if  txtShortDescription.text == ""
    {
        self.lblShortDescription.hidden = false
    }
    else
    {
        self.lblShortDescription.hidden = true
    }

}

import UIKit
import RxSwift

@IBDesignable class TextViewWithPlaceholder: UITextView {
    
    //MARK: - Propertise
    @IBInspectable var placeholderText: String = ""
    
    let placeholderLabel = LocalizedUILabel()
    private let hidePlaceholderObserver = PublishSubject<Bool>()
    let disposeBag = DisposeBag()
    
    
    //MARK: - Did Move To Window
    override func didMoveToWindow() {
        super.didMoveToWindow()
        observeOnTextViewEditing()
        configurePlaceholder()
    }
    
    
    //MARK: - Observe On Text View Editing
    private func observeOnTextViewEditing() {
        rx.text.subscribe(onNext: { [weak self] selectedText in
            guard let self = self else { return }
            self.hidePlaceholderObserver.onNext((selectedText?.isEmpty ?? true) ? false : true)
            
        }).disposed(by: disposeBag)
    }
    
    
    //MARK: - Observe On Show Hide Placeholder
    private func configurePlaceholder() {
        hidePlaceholderObserver
            .bind(to: placeholderLabel.rx.isHidden)
            .disposed(by: disposeBag)
        
        placeholderLabel.text = placeholderText
        placeholderLabel.font = UIFont(name: "Poppins-Semibold", size: 16) ?? UIFont()
        placeholderLabel.textColor = .lightGray
        
        placeholderLabel.sizeToFit()
        placeholderLabel.frame.origin = CGPoint(x: 8, y: 8)
        addSubview(placeholderLabel)
    }
    
}