好吧，我的阴沟有点不同 我创建了一个小班来为你做这件事。

TextViewShader。m文件

#import "TextViewShader.h"

@implementation TextViewShader
-(id)initWithShadedTextView:(NSString *)text textViewToShade:(UITextView *)textview {
    self = [super initWithFrame:textview.frame];
    if (self) {
        if (shadeLabel==nil)
        {
            shadeLabel= [[UILabel alloc]initWithFrame:CGRectMake(10, 0, textview.frame.size.width, 30)];


    }
    shadeLabel.text =text;// @"Enter Your Support Request";
    shadeLabel.textColor = [UIColor lightGrayColor];
    [textview setDelegate: self];
    [textview addSubview:shadeLabel];
}
return self;
}

-(void)textViewDidChange:(UITextView *)textView{
        if (textView.text.length==0)
        {
            shadeLabel.hidden=false; 
        }
        else
        {
            shadeLabel.hidden=true;
        }

}

@end

TextViewShader.h文件

#import <UIKit/UIKit.h>

@interface TextViewShader : UIView<UITextViewDelegate>{
    UILabel *shadeLabel;

}
-(id)initWithShadedTextView:(NSString *)text textViewToShade:(UITextView *)textview ;
@end

这是简单的一行代码使用(不要忘记添加#import "TextViewShader.h")

 TextViewShader* shader = [[TextViewShader alloc]initWithShadedTextView:@"Enter Your Support Request" textViewToShade: youruitextviewToshade];

玩得开心!

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
    }
 }
}

简单地创建UITextView的@IBDesignable子类:

@IBDesignable class AttributedTextView: UITextView {

    private let placeholderLabel = UILabel()

    @IBInspectable var placeholder: String = "" {

        didSet {

            setupPlaceholderLabelIfNeeded()
            textViewDidChange()
        }
    }

    override var text: String! {

        didSet {
            textViewDidChange()
        }
    }

    //MARK: - Initialization

    override func awakeFromNib() {
        super.awakeFromNib()

        setupPlaceholderLabelIfNeeded()
        NotificationCenter.default.addObserver(self, selector: #selector(textViewDidChange), name: .UITextViewTextDidChange, object: nil)
    }

    //MARK: - Deinitialization

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    //MARK: - Internal

    func textViewDidChange() {

        placeholderLabel.isHidden = !text.isEmpty
        layoutIfNeeded()
    }

    //MARK: - Private

    private func setupPlaceholderLabelIfNeeded() {

        placeholderLabel.removeFromSuperview()
        placeholderLabel.frame = CGRect(x: 0, y: 8, width: frame.size.width, height: 0)
        placeholderLabel.textColor = UIColor.lightGray
        placeholderLabel.text = placeholder

        placeholderLabel.sizeToFit()

        insertSubview(placeholderLabel, at: 0)
    }
}

然后在标识检查器中设置占位符:

更简单，并且仍然考虑到用户在某些时候输入的一些文本

BOOL placeHolderTextVisible;

在viewDidLoad上，设置它为YES(或DidMoveToSuperview，或awakeFromNib)

然后,在 - (BOOL) textView:(UITextView*)textView shouldBeginEditing

    - (BOOL)textViewShouldBeginEditing:(UITextView *)textView;
{
   if (placeHolderTextVisible) {
    placeHolderTextVisible = NO;
    textView.text = @"";
   }
 return YES;
}

下面是“SAMTextView”ObjC代码的Swift端口，作为对这个问题的第一批回答之一。我在iOS 8上进行了测试。我调整了一些东西，包括占位符文本的位置的边界偏移，因为原来的位置太高，太右了(在那个帖子的一个评论中使用了建议)。

我知道有很多简单的解决方案，但我喜欢子类化UITextView的方法，因为它是可重用的，而且我不必在使用它的机制时使类变得混乱。

斯威夫特2.2:

import UIKit

class PlaceholderTextView: UITextView {

    @IBInspectable var placeholderColor: UIColor = UIColor.lightGrayColor()
    @IBInspectable var placeholderText: String = ""

    override var font: UIFont? {
        didSet {
            setNeedsDisplay()
        }
    }

    override var contentInset: UIEdgeInsets {
        didSet {
            setNeedsDisplay()
        }
    }

    override var textAlignment: NSTextAlignment {
        didSet {
            setNeedsDisplay()
        }
    }

    override var text: String? {
        didSet {
            setNeedsDisplay()
        }
    }

    override var attributedText: NSAttributedString? {
        didSet {
            setNeedsDisplay()
        }
    }

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

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

    private func setUp() {
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PlaceholderTextView.textChanged(_:)),
                                                         name: UITextViewTextDidChangeNotification, object: self)
    }

    func textChanged(notification: NSNotification) {
        setNeedsDisplay()
    }

    func placeholderRectForBounds(bounds: CGRect) -> CGRect {
        var x = contentInset.left + 4.0
        var y = contentInset.top  + 9.0
        let w = frame.size.width - contentInset.left - contentInset.right - 16.0
        let h = frame.size.height - contentInset.top - contentInset.bottom - 16.0

        if let style = self.typingAttributes[NSParagraphStyleAttributeName] as? NSParagraphStyle {
            x += style.headIndent
            y += style.firstLineHeadIndent
        }
        return CGRect(x: x, y: y, width: w, height: h)
    }

    override func drawRect(rect: CGRect) {
        if text!.isEmpty && !placeholderText.isEmpty {
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.alignment = textAlignment
            let attributes: [ String: AnyObject ] = [
                NSFontAttributeName : font!,
                NSForegroundColorAttributeName : placeholderColor,
                NSParagraphStyleAttributeName  : paragraphStyle]

            placeholderText.drawInRect(placeholderRectForBounds(bounds), withAttributes: attributes)
        }
        super.drawRect(rect)
    }
}

斯威夫特4.2:

import UIKit

class PlaceholderTextView: UITextView {

    @IBInspectable var placeholderColor: UIColor = UIColor.lightGray
    @IBInspectable var placeholderText: String = ""

    override var font: UIFont? {
        didSet {
            setNeedsDisplay()
        }
    }

    override var contentInset: UIEdgeInsets {
        didSet {
            setNeedsDisplay()
        }
    }

    override var textAlignment: NSTextAlignment {
        didSet {
            setNeedsDisplay()
        }
    }

    override var text: String? {
        didSet {
            setNeedsDisplay()
        }
    }

    override var attributedText: NSAttributedString? {
        didSet {
            setNeedsDisplay()
        }
    }

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

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

    private func setUp() {
        NotificationCenter.default.addObserver(self,
         selector: #selector(self.textChanged(notification:)),
         name: Notification.Name("UITextViewTextDidChangeNotification"),
         object: nil)
    }

    @objc func textChanged(notification: NSNotification) {
        setNeedsDisplay()
    }

    func placeholderRectForBounds(bounds: CGRect) -> CGRect {
        var x = contentInset.left + 4.0
        var y = contentInset.top  + 9.0
        let w = frame.size.width - contentInset.left - contentInset.right - 16.0
        let h = frame.size.height - contentInset.top - contentInset.bottom - 16.0

        if let style = self.typingAttributes[NSAttributedString.Key.paragraphStyle] as? NSParagraphStyle {
            x += style.headIndent
            y += style.firstLineHeadIndent
        }
        return CGRect(x: x, y: y, width: w, height: h)
    }

    override func draw(_ rect: CGRect) {
        if text!.isEmpty && !placeholderText.isEmpty {
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.alignment = textAlignment
            let attributes: [NSAttributedString.Key: Any] = [
            NSAttributedString.Key(rawValue: NSAttributedString.Key.font.rawValue) : font!,
            NSAttributedString.Key(rawValue: NSAttributedString.Key.foregroundColor.rawValue) : placeholderColor,
            NSAttributedString.Key(rawValue: NSAttributedString.Key.paragraphStyle.rawValue)  : paragraphStyle]

            placeholderText.draw(in: placeholderRectForBounds(bounds: bounds), withAttributes: attributes)
        }
        super.draw(rect)
    }
}

这完美地模仿了UITextField的占位符，其中占位符文本一直保留到您实际键入一些内容为止。

private let placeholder = "Type here"

@IBOutlet weak var textView: UITextView! {
    didSet {
        textView.textColor = UIColor.lightGray
        textView.text = placeholder
        textView.selectedRange = NSRange(location: 0, length: 0)
    }
}

extension ViewController: UITextViewDelegate {

    func textViewDidChangeSelection(_ textView: UITextView) {
        // Move cursor to beginning on first tap
        if textView.text == placeholder {
            textView.selectedRange = NSRange(location: 0, length: 0)
        }
    }

    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        if textView.text == placeholder && !text.isEmpty {
            textView.text = nil
            textView.textColor = UIColor.black
            textView.selectedRange = NSRange(location: 0, length: 0)
        }
        return true
    }

    func textViewDidChange(_ textView: UITextView) {
        if textView.text.isEmpty {
            textView.textColor = UIColor.lightGray
            textView.text = placeholder
        }
    }
}