非常容易工作的解决方案使用代码和故事板。

通过代码

textView.scrollEnabled = false

通过故事板

取消选中“滚动启用”

除此之外什么都不用做。

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。

基于Nikita Took的回答，我想出了以下解决方案，适用于iOS 8的自动布局:

    descriptionTxt.scrollEnabled = false
    descriptionTxt.text = yourText

    var contentSize = descriptionTxt.sizeThatFits(CGSizeMake(descriptionTxt.frame.size.width, CGFloat.max))
    for c in descriptionTxt.constraints() {
        if c.isKindOfClass(NSLayoutConstraint) {
            var constraint = c as! NSLayoutConstraint
            if constraint.firstAttribute == NSLayoutAttribute.Height {
                constraint.constant = contentSize.height
                break
            }
        }
    }

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。

The easiest way to ask a UITextView is just calling -sizeToFitit should work also with scrollingEnabled = YES, after that check for the height and add a height constraint on the text view with the same value. Pay attention that UITexView contains insets, this means that you can't ask the string object how much space it want to use, because this is just the bounding rect of the text. All the person that are experiencing wrong size using -sizeToFit it's probably due to the fact that the text view has not been layout yet to the interface size. This always happen when you use size classes and a UITableView, the first time cells are created in the - tableView:cellForRowAtIndexPath: the comes out with the size of the any-any configuration, if you compute you value just now the text view will have a different width than the expected and this will screw all sizes. To overcome this issue I've found useful to override the -layoutSubviews method of the cell to recalculate textview height.

你试过[textView sizeThatFits:textView. txt]吗?范围)?

编辑:sizeThatFits返回大小，但并不实际调整组件的大小。我不确定如果这是你想要的，或者如果[textView sizeToFit]是更多的你要寻找的。无论哪种情况，我不知道它是否完全适合你想要的内容，但这是第一件要尝试的事情。