我已经创建了一个快速3版本的最高排名的答案

你只需要做UITextView的子类化。

import UIKit

 class UIPlaceHolderTextView: UITextView {


//MARK: - Properties
@IBInspectable var placeholder: String?
@IBInspectable var placeholderColor: UIColor?
var placeholderLabel: UILabel?


//MARK: - Initializers
override func awakeFromNib() {
    super.awakeFromNib()


}

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

    // Use Interface Builder User Defined Runtime Attributes to set
    // placeholder and placeholderColor in Interface Builder.
    if self.placeholder == nil {
        self.placeholder = ""
    }

    if self.placeholderColor == nil {
        self.placeholderColor = UIColor.black
    }

    NotificationCenter.default.addObserver(self, selector: #selector(textChanged(_:)), name: NSNotification.Name.UITextViewTextDidChange, object: nil)

}

func textChanged(_ notification: Notification) -> Void {
    if self.placeholder?.count == 0 {
        return
    }

    UIView.animate(withDuration: 0.25) {
        if self.text.count == 0 {
            self.viewWithTag(999)?.alpha = 1
        }
        else {
            self.viewWithTag(999)?.alpha = 0
        }
    }
}

// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
    super.draw(rect)

    if (self.placeholder?.count ?? 0) > 0 {
        if placeholderLabel == nil {
            placeholderLabel = UILabel.init()
            placeholderLabel?.lineBreakMode = .byWordWrapping
            placeholderLabel?.numberOfLines = 0
            placeholderLabel?.font = self.font
            placeholderLabel?.backgroundColor = self.backgroundColor
            placeholderLabel?.textColor = self.placeholderColor
            placeholderLabel?.alpha = 0
            placeholderLabel?.tag = 999
            self.addSubview(placeholderLabel!)

            placeholderLabel?.translatesAutoresizingMaskIntoConstraints = false
            placeholderLabel?.topAnchor.constraint(equalTo: self.topAnchor, constant: 7).isActive = true
            placeholderLabel?.leftAnchor.constraint(equalTo: self.leftAnchor, constant: 4).isActive = true
            placeholderLabel?.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
            placeholderLabel?.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        }

        placeholderLabel?.text = self.placeholder
        placeholderLabel?.sizeToFit()
        self.sendSubview(toBack: self.placeholderLabel!)
    }

    if self.text.count == 0 && (self.placeholder?.count ?? 0) > 0 {
        self.viewWithTag(999)?.alpha = 1
    }
 }
}

我通读了所有这些，但提出了一个非常简短的Swift 3解决方案，在我的所有测试中都有效。它可以更一般化一点，但过程很简单。这是整个东西，我称之为“TextViewWithPlaceholder”。

import UIKit

class TextViewWithPlaceholder: UITextView {

    public var placeholder: String?
    public var placeholderColor = UIColor.lightGray

    private var placeholderLabel: UILabel?

    // Set up notification listener when created from a XIB or storyboard.
    // You can also set up init() functions if you plan on creating
    // these programmatically.
    override func awakeFromNib() {
        super.awakeFromNib()

        NotificationCenter.default.addObserver(self,
                                           selector: #selector(TextViewWithPlaceholder.textDidChangeHandler(notification:)),
                                           name: .UITextViewTextDidChange,
                                           object: self)

        placeholderLabel = UILabel()
        placeholderLabel?.alpha = 0.85
        placeholderLabel?.textColor = placeholderColor
    }

    // By using layoutSubviews, you can size and position the placeholder
    // more accurately. I chose to hard-code the size of the placeholder
    // but you can combine this with other techniques shown in previous replies.
    override func layoutSubviews() {
        super.layoutSubviews()

        placeholderLabel?.textColor = placeholderColor
        placeholderLabel?.text = placeholder

        placeholderLabel?.frame = CGRect(x: 6, y: 4, width: self.bounds.size.width-16, height: 24)

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

    // Whenever the text changes, just trigger a new layout pass.
    func textDidChangeHandler(notification: Notification) {
        layoutSubviews()
    }
}

TextView占位符

import UIKit

@IBDesignable
open class KMPlaceholderTextView: UITextView {

    private struct Constants {
        static let defaultiOSPlaceholderColor = UIColor(red: 0.0, green: 0.0, blue: 0.0980392, alpha: 0.22)
    }

    public let placeholderLabel: UILabel = UILabel()

    private var placeholderLabelConstraints = [NSLayoutConstraint]()

    @IBInspectable open var placeholder: String = "" {
        didSet {
            placeholderLabel.text = placeholder
        }
    }

    @IBInspectable open var placeholderColor: UIColor = KMPlaceholderTextView.Constants.defaultiOSPlaceholderColor {
        didSet {
            placeholderLabel.textColor = placeholderColor
        }
    }

    override open var font: UIFont! {
        didSet {
            if placeholderFont == nil {
                placeholderLabel.font = font
            }
        }
    }

    open var placeholderFont: UIFont? {
        didSet {
            let font = (placeholderFont != nil) ? placeholderFont : self.font
            placeholderLabel.font = font
        }
    }

    override open var textAlignment: NSTextAlignment {
        didSet {
            placeholderLabel.textAlignment = textAlignment
        }
    }

    override open var text: String! {
        didSet {
            textDidChange()
        }
    }

    override open var attributedText: NSAttributedString! {
        didSet {
            textDidChange()
        }
    }

    override open var textContainerInset: UIEdgeInsets {
        didSet {
            updateConstraintsForPlaceholderLabel()
        }
    }

    override public init(frame: CGRect, textContainer: NSTextContainer?) {
        super.init(frame: frame, textContainer: textContainer)
        commonInit()
    }

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

    private func commonInit() {
        #if swift(>=4.2)
        let notificationName = UITextView.textDidChangeNotification
        #else
        let notificationName = NSNotification.Name.UITextView.textDidChangeNotification
        #endif

        NotificationCenter.default.addObserver(self,
                                               selector: #selector(textDidChange),
                                               name: notificationName,
                                               object: nil)

        placeholderLabel.font = font
        placeholderLabel.textColor = placeholderColor
        placeholderLabel.textAlignment = textAlignment
        placeholderLabel.text = placeholder
        placeholderLabel.numberOfLines = 0
        placeholderLabel.backgroundColor = UIColor.clear
        placeholderLabel.translatesAutoresizingMaskIntoConstraints = false
        addSubview(placeholderLabel)
        updateConstraintsForPlaceholderLabel()
    }

    private func updateConstraintsForPlaceholderLabel() {
        var newConstraints = NSLayoutConstraint.constraints(withVisualFormat: "H:|-(\(textContainerInset.left + textContainer.lineFragmentPadding))-[placeholder]",
            options: [],
            metrics: nil,
            views: ["placeholder": placeholderLabel])
        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "V:|-(\(textContainerInset.top))-[placeholder]",
            options: [],
            metrics: nil,
            views: ["placeholder": placeholderLabel])
        newConstraints.append(NSLayoutConstraint(
            item: placeholderLabel,
            attribute: .width,
            relatedBy: .equal,
            toItem: self,
            attribute: .width,
            multiplier: 1.0,
            constant: -(textContainerInset.left + textContainerInset.right + textContainer.lineFragmentPadding * 2.0)
        ))
        removeConstraints(placeholderLabelConstraints)
        addConstraints(newConstraints)
        placeholderLabelConstraints = newConstraints
    }

    @objc private func textDidChange() {
        placeholderLabel.isHidden = !text.isEmpty
        self.layoutIfNeeded()
    }

    open override func layoutSubviews() {
        super.layoutSubviews()
        placeholderLabel.preferredMaxLayoutWidth = textContainer.size.width - textContainer.lineFragmentPadding * 2.0
    }

    deinit {
        #if swift(>=4.2)
        let notificationName = UITextView.textDidChangeNotification
        #else
        let notificationName = NSNotification.Name.UITextView.textDidChangeNotification
        #endif

        NotificationCenter.default.removeObserver(self,
                                                  name: notificationName,
                                                  object: nil)
    }

}

使用

如果有人需要Swift的解决方案:

添加UITextViewDelegate到类中

var placeHolderText = "Placeholder Text..."

override func viewDidLoad() {
    super.viewDidLoad()
    textView.delegate = self
}

func textViewShouldBeginEditing(textView: UITextView) -> Bool {

    self.textView.textColor = .black

    if(self.textView.text == placeHolderText) {
        self.textView.text = ""
    }

    return true
}

func textViewDidEndEditing(textView: UITextView) {
    if(textView.text == "") {
        self.textView.text = placeHolderText
        self.textView.textColor = .lightGray
    }
}

override func viewWillAppear(animated: Bool) {

    if(currentQuestion.answerDisplayValue == "") {
        self.textView.text = placeHolderText
        self.textView.textColor = .lightGray
    } else {
        self.textView.text = "xxx" // load default text / or stored 
        self.textView.textColor = .black
    }
}

看一下UTPlaceholderTextView。

这是UITextView的一个方便的子类，它支持类似于UITextField的占位符。主要特点:

不使用子视图 不重写drawRect: 占位符的长度可以是任意的，并以与通常文本相同的方式呈现

这里有一个简单而聪明的方法来获得完美的行为。

让我们借用UITextField中的占位符。

Set up a textField and set its text transparent. self.placeholderTextField = [[UITextField alloc] init]; /* adjust the frame to fit it in the first line of your textView */ self.placeholderTextField.frame = CGRectMake(0.0, 0.0, yourTextView.width, 30.0); self.placeholderTextField.textColor = [UIColor clearColor]; self.placeholderTextField.userInteractionEnabled = NO; self.placeholderTextField.font = yourTextView.font; self.placeholderTextField.placeholder = @"sample placeholder"; [yourTextView addSubview:self.placeholderTextField]; Set textView's delegate and synchronize the textField and textView. yourTextView.delegate = self; then - (void)textViewDidChange:(UITextView *)textView { self.placeholderTextField.text = textView.text; } That's all.