在代码行中使用它的简单方法:

取一个标签到。nib中的UITextView 将这个标签连接到你的代码， 在它。

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{

    if (range.location>0 || text.length!=0) {
        placeholderLabel1.hidden = YES;
    }else{
        placeholderLabel1.hidden = NO;
    }
    return YES;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    self.textViewEmpty = YES;

    // Text view
    self.textView = [[UITextView alloc] init];
    self.textView.translatesAutoresizingMaskIntoConstraints = NO; // For AutoLayout
    self.textView.delegate = self;
    self.textView.textColor = [UIColor grayColor];
    self.textView.text = @"Placeholder";

    // Add subview and constraints
}

#pragma mark - UITextView

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView {
    if (self.isTextViewEmpty) {
        textView.textColor = [UIColor blackColor];
        textView.text = @"";
    }

    return YES;
}

- (void)textViewDidChange:(UITextView *)textView {
    if (textView.text.length > 0) {
        self.textViewEmpty = NO;
    } else {
        self.textViewEmpty = YES;
    }
}

- (BOOL)textViewShouldEndEditing:(UITextView *)textView {
    if (self.isTextViewEmpty) {
        textView.textColor = [UIColor lightGrayColor];
        textView.text = placeholderText;
    }

    return YES;
}

    - (void)textViewDidChange:(UITextView *)textView
{
    placeholderLabel.hidden = YES;
}

在textview上放一个标签。

另一个答案是:

https://github.com/gcamp/GCPlaceholderTextView

改变类UITextView在IB到GCPlaceholderTextView 并设置占位符属性

我对发布的任何解决方案都不太满意，因为它们有点重。向视图中添加视图并不理想(尤其是在drawRect:)。它们都有漏洞，这也是不可接受的。

这是我的解决方案:SAMTextView

SAMTextView.h

//
//  SAMTextView.h
//  SAMTextView
//
//  Created by Sam Soffes on 8/18/10.
//  Copyright 2010-2013 Sam Soffes. All rights reserved.
//

#import <UIKit/UIKit.h>

/**
 UITextView subclass that adds placeholder support like UITextField has.
 */
@interface SAMTextView : UITextView

/**
 The string that is displayed when there is no other text in the text view.

 The default value is `nil`.
 */
@property (nonatomic, strong) NSString *placeholder;

/**
 The color of the placeholder.

 The default is `[UIColor lightGrayColor]`.
 */
@property (nonatomic, strong) UIColor *placeholderTextColor;

/**
 Returns the drawing rectangle for the text views’s placeholder text.

 @param bounds The bounding rectangle of the receiver.
 @return The computed drawing rectangle for the placeholder text.
 */
- (CGRect)placeholderRectForBounds:(CGRect)bounds;

@end

SAMTextView.m

//
//  SAMTextView.m
//  SAMTextView
//
//  Created by Sam Soffes on 8/18/10.
//  Copyright 2010-2013 Sam Soffes. All rights reserved.
//

#import "SAMTextView.h"

@implementation SAMTextView

#pragma mark - Accessors

@synthesize placeholder = _placeholder;
@synthesize placeholderTextColor = _placeholderTextColor;

- (void)setText:(NSString *)string {
  [super setText:string];
  [self setNeedsDisplay];
}


- (void)insertText:(NSString *)string {
  [super insertText:string];
  [self setNeedsDisplay];
}


- (void)setAttributedText:(NSAttributedString *)attributedText {
  [super setAttributedText:attributedText];
  [self setNeedsDisplay];
}


- (void)setPlaceholder:(NSString *)string {
  if ([string isEqual:_placeholder]) {
    return;
  }

  _placeholder = string;
  [self setNeedsDisplay];
}


- (void)setContentInset:(UIEdgeInsets)contentInset {
  [super setContentInset:contentInset];
  [self setNeedsDisplay];
}


- (void)setFont:(UIFont *)font {
  [super setFont:font];
  [self setNeedsDisplay];
}


- (void)setTextAlignment:(NSTextAlignment)textAlignment {
  [super setTextAlignment:textAlignment];
  [self setNeedsDisplay];
}


#pragma mark - NSObject

- (void)dealloc {
  [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidChangeNotification object:self];
}


#pragma mark - UIView

- (id)initWithCoder:(NSCoder *)aDecoder {
  if ((self = [super initWithCoder:aDecoder])) {
    [self initialize];
  }
  return self;
}


- (id)initWithFrame:(CGRect)frame {
  if ((self = [super initWithFrame:frame])) {
    [self initialize];
  }
  return self;
}


- (void)drawRect:(CGRect)rect {
  [super drawRect:rect];

  if (self.text.length == 0 && self.placeholder) {
    rect = [self placeholderRectForBounds:self.bounds];

    UIFont *font = self.font ? self.font : self.typingAttributes[NSFontAttributeName];

    // Draw the text
    [self.placeholderTextColor set];
    [self.placeholder drawInRect:rect withFont:font lineBreakMode:NSLineBreakByTruncatingTail alignment:self.textAlignment];
  }
}


#pragma mark - Placeholder

- (CGRect)placeholderRectForBounds:(CGRect)bounds {
  // Inset the rect
  CGRect rect = UIEdgeInsetsInsetRect(bounds, self.contentInset);

  if (self.typingAttributes) {
    NSParagraphStyle *style = self.typingAttributes[NSParagraphStyleAttributeName];
    if (style) {
      rect.origin.x += style.headIndent;
      rect.origin.y += style.firstLineHeadIndent;
    }
  }

  return rect;
}


#pragma mark - Private

- (void)initialize {
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:self];

  self.placeholderTextColor = [UIColor colorWithWhite:0.702f alpha:1.0f];
}


- (void)textChanged:(NSNotification *)notification {
  [self setNeedsDisplay];
}

@end

它比其他的要简单得多，因为它不使用子视图(或有泄漏)。请随意使用。

更新11/10/11:它现在是文档化的，并支持在接口生成器中使用。

更新11/24/13:指向新的回购。

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)
    }
}