这里还有另一种方法，它复制了UITextField占位符的轻微缩进:

将UITextField拖到UITextView的右边，这样它们的左上角就对齐了。将占位符文本添加到文本字段。

在viewDidLoad中添加:

[tView setDelegate:self];
tView.contentInset = UIEdgeInsetsMake(-8,-8,0,0);
tView.backgroundColor = [UIColor clearColor];

然后添加:

- (void)textViewDidChange:(UITextView *)textView {
    if (textView.text.length == 0) {
        textView.backgroundColor = [UIColor clearColor];            
    } else {
        textView.backgroundColor = [UIColor whiteColor];
    }
}

我扩展了KmKndy的答案，这样在用户开始编辑UITextView之前，占位符仍然是可见的，而不仅仅是点击它。这反映了Twitter和Facebook应用程序的功能。我的解决方案不需要你子类和工作，如果用户类型直接或粘贴文本!

- (void)textViewDidChangeSelection:(UITextView *)textView{
    if ([textView.text isEqualToString:@"What's happening?"] && [textView.textColor isEqual:[UIColor lightGrayColor]])[textView setSelectedRange:NSMakeRange(0, 0)];

}

- (void)textViewDidBeginEditing:(UITextView *)textView{

    [textView setSelectedRange:NSMakeRange(0, 0)];
}

- (void)textViewDidChange:(UITextView *)textView
{
    if (textView.text.length != 0 && [[textView.text substringFromIndex:1] isEqualToString:@"What's happening?"] && [textView.textColor isEqual:[UIColor lightGrayColor]]){
        textView.text = [textView.text substringToIndex:1];
        textView.textColor = [UIColor blackColor]; //optional

    }
    else if(textView.text.length == 0){
        textView.text = @"What's happening?";
        textView.textColor = [UIColor lightGrayColor];
        [textView setSelectedRange:NSMakeRange(0, 0)];
    }
}

- (void)textViewDidEndEditing:(UITextView *)textView
{
    if ([textView.text isEqualToString:@""]) {
        textView.text = @"What's happening?";
        textView.textColor = [UIColor lightGrayColor]; //optional
    }
    [textView resignFirstResponder];
}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
    if (textView.text.length > 1 && [textView.text isEqualToString:@"What's happening?"]) {
         textView.text = @"";
         textView.textColor = [UIColor blackColor];
    }

    return YES;
}

只需要记住在创建时使用准确的文本设置myUITextView即可。

UITextView *myUITextView = [[UITextView alloc] init];
myUITextView.delegate = self;
myUITextView.text = @"What's happening?";
myUITextView.textColor = [UIColor lightGrayColor]; //optional

在包含这些方法之前，让父类成为一个UITextView委托。

@interface MyClass () <UITextViewDelegate>
@end

我找到了一个很容易模仿占位符的方法

在NIB或代码设置你的textView的textColor为lightGrayColor(大多数时候) 确保你的textView的委托链接到文件的所有者和实现UITextViewDelegate在你的头文件 将文本视图的默认文本设置为(例如:"Foobar placeholder") 实现:(BOOL) textViewShouldBeginEditing:(UITextView *)textView

编辑:

Changed if statements to compare tags rather than text. If the user deleted their text it was possible to also accidentally delete a portion of the place holder @"Foobar placeholder".This meant if the user re-entered the textView the following delegate method, -(BOOL) textViewShouldBeginEditing:(UITextView *) textView, it would not work as expected. I tried comparing by the color of the text in the if statement but found that light grey color set in interface builder is not the same as light grey color set in code with [UIColor lightGreyColor]

- (BOOL) textViewShouldBeginEditing:(UITextView *)textView
{
    if(textView.tag == 0) {
        textView.text = @"";
        textView.textColor = [UIColor blackColor];
        textView.tag = 1;
    }
    return YES;
}

当键盘返回并且[textView length] == 0时，也可以重置占位符文本

编辑:

只是为了让最后一部分更清楚——下面是如何将占位符文本设置回去:

- (void)textViewDidChange:(UITextView *)textView
{
   if([textView.text length] == 0)
   {
       textView.text = @"Foobar placeholder";
       textView.textColor = [UIColor lightGrayColor];
       textView.tag = 0;
   }
}

抱歉添加了另一个答案，但我只是拉出了这样的东西，这创建了最接近uitextfield的占位符。

希望这能帮助到一些人。

-(void)textViewDidChange:(UITextView *)textView{
    if(textView.textColor == [UIColor lightGrayColor]){
        textView.textColor  = [UIColor blackColor]; // look at the comment section in this answer
        textView.text       = [textView.text substringToIndex: 0];// look at the comment section in this answer
    }else if(textView.text.length == 0){
        textView.text       = @"This is some placeholder text.";
        textView.textColor  = [UIColor lightGrayColor];
        textView.selectedRange = NSMakeRange(0, 0);
    }
}

-(void)textViewDidChangeSelection:(UITextView *)textView{
    if(textView.textColor == [UIColor lightGrayColor] && (textView.selectedRange.location != 0 || textView.selectedRange.length != 0)){
        textView.selectedRange = NSMakeRange(0, 0);
    }
}

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:

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];
}