如果你正在寻找一个简单的方法来实现这一点，试试我的方法:

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

    return YES;
}

-(BOOL)textViewShouldEndEditing:(UITextView *)textView
{
    if ([[textView text] length] == 0) {
        textView.text = PLACE_HOLDER_TEXT;
        textView.textColor = [UIColor lightGrayColor];
    }
    return YES;
}

是的，就是它PLACE_HOLDER_TEXT是一个NSString包含你的占位符

让我们简单点

创建一个UILabel并把它放在你的文本视图上(给文本作为占位符-设置颜色为灰色-你可以在你的xib中做这一切) 现在在头文件中声明UILabel和textviewDelegate 现在你可以简单地隐藏标签，当你点击textview

完整代码如下

头

@interface ViewController :UIViewController<UITextViewDelegate>{
 }
   @property (nonatomic,strong) IBOutlet UILabel *PlceHolder_label;
   @property (nonatomic,strong) IBOutlet UITextView *TextView;

@end

实现

@implementation UploadFoodImageViewController
@synthesize PlceHolder_label,TextView;

  - (void)viewDidLoad
    {
       [super viewDidLoad];
    }


 - (BOOL)textViewShouldBeginEditing:(UITextView *)textView{

       if([textView isEqual:TextView]){
            [PlceHolder_label setHidden:YES];
            [self.tabScrlVw setContentOffset:CGPointMake(0,150) animated:YES];
          }
      return YES;
    }

@end

别忘了连接textView和UILabel文件所有者从xib

Jason的答案在iOS7中看起来有点不对劲，通过调整_placeHolderLabel的偏移量来修复它:

- (void)drawRect:(CGRect)rect
{
    if( [[self placeholder] length] > 0 )
    {
        if (_placeHolderLabel == nil )
        {
            if ([[UIDevice currentDevice].systemVersion floatValue] >= 7)
                _placeHolderLabel = [[UILabel alloc] initWithFrame:CGRectMake(4,8,self.bounds.size.width - 8,0)];
            else
                _placeHolderLabel = [[UILabel alloc] initWithFrame:CGRectMake(8,8,self.bounds.size.width - 16,0)];
            _placeHolderLabel.lineBreakMode = NSLineBreakByWordWrapping;
            _placeHolderLabel.numberOfLines = 0;
            _placeHolderLabel.font = self.font;
            _placeHolderLabel.backgroundColor = [UIColor clearColor];
            _placeHolderLabel.textColor = self.placeholderColor;
            _placeHolderLabel.alpha = 0;
            _placeHolderLabel.tag = 999;
            [self addSubview:_placeHolderLabel];
        }

        _placeHolderLabel.text = self.placeholder;
        [_placeHolderLabel sizeToFit];
        [self sendSubviewToBack:_placeHolderLabel];
    }

    if( [[self text] length] == 0 && [[self placeholder] length] > 0 )
    {
        [[self viewWithTag:999] setAlpha:1];
    }

    [super drawRect: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
        }
    }
}

基于这里已经给出的一些很好的建议，我能够将以下轻量级的、与接口生成器兼容的UITextView子类组合在一起，它是:

包括可配置的占位符文本，样式就像UITextField一样。 不需要任何额外的子视图或约束。 不需要来自ViewController的任何委托或其他行为。 不需要任何通知。 保持该文本与查看字段的文本属性的任何外部类完全分离。

欢迎提出改进建议。

编辑1:更新为重置占位符格式，如果实际文本以编程方式设置。

编辑2:现在可以以编程方式检索占位符文本颜色。

斯威夫特v5:

import UIKit
@IBDesignable class TextViewWithPlaceholder: UITextView {
    
    override var text: String! { // Ensures that the placeholder text is never returned as the field's text
        get {
            if showingPlaceholder {
                return "" // When showing the placeholder, there's no real text to return
            } else { return super.text }
        }
        set {
            if showingPlaceholder {
                removePlaceholderFormatting() // If the placeholder text is what's being changed, it's no longer the placeholder
            }
            super.text = newValue
        }
    }
    @IBInspectable var placeholderText: String = ""
    @IBInspectable var placeholderTextColor: UIColor = .placeholderText
    private var showingPlaceholder: Bool = true // Keeps track of whether the field is currently showing a placeholder
    
    override func didMoveToWindow() {
        super.didMoveToWindow()
        if text.isEmpty {
            showPlaceholderText() // Load up the placeholder text when first appearing, but not if coming back to a view where text was already entered
        }
    }
    
    override public func becomeFirstResponder() -> Bool {
        
        // If the current text is the placeholder, remove it
        if showingPlaceholder {
            text = nil
            removePlaceholderFormatting()
        }
        return super.becomeFirstResponder()
    }
    
    override public func resignFirstResponder() -> Bool {
        
        // If there's no text, put the placeholder back
        if text.isEmpty {
            showPlaceholderText()
        }
        return super.resignFirstResponder()
    }
    
    private func showPlaceholderText() {
        
        text = placeholderText
        showingPlaceholder = true
        textColor = placeholderTextColor
    }
    
    private func removePlaceholderFormatting() {
        
        showingPlaceholder = false
        textColor = nil // Put the text back to the default, unmodified color
    }
}

斯威夫特3.1

在尝试了所有快速的答案之后，这个答案将为我节省3个小时的研究时间。希望这能有所帮助。

确保你的textField(不管你有什么自定义名称)指向它在Storyboard中的委托，并且有一个@IBOutlet和你的customtextfield 将以下内容添加到viewDidLoad()中，加载视图时会出现:

告诉我什么看起来是占位符:

yourCustomTextField = "Start typing..." 
yourCustomTextField.textColor = .lightGray

在viewDidLoad外部但在同一个类内部添加以下声明:UIViewController, UITextViewDelegate, UINavigationControllerDelegate

这段代码将使yourCustomTextField在输入textField时消失:

func textViewDidBeginEditing (_ textView: UITextView) { 

    if (textView.text == "Start typing...") {

        textView.text = ""
        textView.textColor = .black
    }

    textView.becomeFirstResponder()
}

func textViewDidEndEditing(_ textView: UITextView) {
    if (textView.text == "") {

        textView.text = "Start typing..."
        textView.textColor = .lightGray
    }

    textView.resignFirstResponder()
}