根据我有限的经验，

- (CGSize)sizeWithFont:(UIFont *)font forWidth:(CGFloat)width lineBreakMode:(UILineBreakMode)lineBreakMode

不尊重换行符，所以你最终可以得到比实际需要的更短的CGSize。

- (CGSize)sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size

看起来很尊重换行符。

同样，文本也不是在UITextView顶部渲染的。在我的代码中，我将UITextView的新高度设置为比sizeOfFont方法返回的高度大24个像素。

禁用滚动

添加constaints

然后添加文本

[yourTextView setText:@"your text"];
[yourTextView layoutIfNeeded];

如果你使用UIScrollView，你也应该添加这个;

[yourScrollView layoutIfNeeded];

-(void)viewDidAppear:(BOOL)animated{
    CGRect contentRect = CGRectZero;

    for (UIView *view in self.yourScrollView.subviews) {
         contentRect = CGRectUnion(contentRect, view.frame);
    }
    self.yourScrollView.contentSize = contentRect.size;
}

用键值观察(KVO)很简单，只需创建UITextView的子类，然后做:

private func setup() { // Called from init or somewhere

    fitToContentObservations = [
        textView.observe(\.contentSize) { _, _ in
            self.invalidateIntrinsicContentSize()
        },
        // For some reason the content offset sometimes is non zero even though the frame is the same size as the content size.
        textView.observe(\.contentOffset) { _, _ in
            if self.contentOffset != .zero { // Need to check this to stop infinite loop
                self.contentOffset = .zero
            }
        }
    ]
}
public override var intrinsicContentSize: CGSize {
    return contentSize
}

如果你不想子类化，你可以尝试做textView。bounds = textView。contentSize观察者中的contentSize。

在iOS6中，你可以在设置文本后检查UITextView的contentSize属性。在iOS7中，这将不再有效。如果你想在iOS7中恢复这个行为，把下面的代码放在UITextView的子类中。

- (void)setText:(NSString *)text
{
    [super setText:text];

    if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1) {
        CGRect rect = [self.textContainer.layoutManager usedRectForTextContainer:self.textContainer];
        UIEdgeInsets inset = self.textContainerInset;
        self.contentSize = UIEdgeInsetsInsetRect(rect, inset).size;
    }
}

如果有其他人来这里，这个解决方案为我工作，1“Ronnie Liew”+4“user63934”(我的文本从web服务到达): 注意1000(在我的情况下，没有什么比这更大了)

UIFont *fontNormal = [UIFont fontWithName:FONTNAME size:FONTSIZE];

NSString *dealDescription = [client objectForKey:@"description"];

//4
CGSize textSize = [dealDescription sizeWithFont:fontNormal constrainedToSize:CGSizeMake(containerUIView.frame.size.width, 1000)];

CGRect dealDescRect = CGRectMake(10, 300, containerUIView.frame.size.width, textSize.height);

UITextView *dealDesc = [[[UITextView alloc] initWithFrame:dealDescRect] autorelease];

dealDesc.text = dealDescription;
//add the subview to the container
[containerUIView addSubview:dealDesc];

//1) after adding the view
CGRect frame = dealDesc.frame;
frame.size.height = dealDesc.contentSize.height;
dealDesc.frame = frame;

那就是……干杯

以下是步骤

解决方案适用于所有版本的iOS。Swift 3.0及以上版本。

添加你的UITextView到View。我用代码添加它，你可以通过界面生成器添加。 添加约束。我在代码中添加约束，你也可以在接口生成器中这样做。 使用UITextViewDelegate方法func textViewDidChange(_ textView: UITextView)来调整textView的大小

代码:

//1. Add your UITextView in ViewDidLoad let textView = UITextView() textView.frame = CGRect(x: 0, y: 0, width: 200, height: 100) textView.backgroundColor = .lightGray textView.text = "Here is some default text." //2. Add constraints textView.translatesAutoresizingMaskIntoConstraints = false [ textView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor), textView.leadingAnchor.constraint(equalTo: view.leadingAnchor), textView.trailingAnchor.constraint(equalTo: view.trailingAnchor), textView.heightAnchor.constraint(equalToConstant: 50), textView.widthAnchor.constraint(equalToConstant: 30) ].forEach{ $0.isActive = true } textView.font = UIFont.preferredFont(forTextStyle: .headline) textView.delegate = self textView.isScrollEnabled = false textViewDidChange(textView) //3. Implement the delegate method. func textViewDidChange(_ textView: UITextView) { let size = CGSize(width: view.frame.width, height: .infinity) let estimatedSize = textView.sizeThatFits(size) textView.constraints.forEach { (constraint) in if constraint.firstAttribute == .height { print("Height: ", estimatedSize.height) constraint.constant = estimatedSize.height } } }