更新

你需要做的关键事情是关闭UITextView中的滚动。

myTextView.scrollEnabled = @NO

原来的答案

要在UITableViewCell中创建一个动态大小的UITextView，我发现以下组合在Xcode 6和iOS 8 SDK中有效:

Add a UITextView to a UITableViewCell and constrain it to the sides Set the UITextView's scrollEnabled property to NO. With scrolling enabled, the frame of the UITextView is independent of its content size, but with scrolling disabled, there is a relationship between the two. If your table is using the original default row height of 44 then it will automatically calculate row heights, but if you changed the default row height to something else, you may need to manually switch on auto-calculation of row heights in viewDidLoad: tableView.estimatedRowHeight = 150; tableView.rowHeight = UITableViewAutomaticDimension;

对于只读动态大小的uitextview，就是这样。如果你允许用户在你的UITextView中编辑文本，你还需要:

实现UITextViewDelegate协议的textViewDidChange:方法，并告诉tableView在每次文本被编辑时重新绘制自己: - (void)textViewDidChange:(UITextView *)textView; ｛ [tableView beginUpdates]; [tableView endUpdates]; ｝ 别忘了在某个地方设置UITextView委托，在Storyboard或者tableView:cellForRowAtIndexPath:

我回顾了所有的答案，所有都保持固定的宽度和调整只有高度。如果你想调整宽度，你可以很容易地使用这个方法:

当配置文本视图时，将滚动设置为禁用

textView.isScrollEnabled = false

然后在委托方法func textViewDidChange(_ textView: UITextView)添加以下代码:

func textViewDidChange(_ textView: UITextView) {
    let newSize = textView.sizeThatFits(CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude))
    textView.frame = CGRect(origin: textView.frame.origin, size: newSize)
}

输出:

我们可以用约束来做。

为UITextView设置高度约束。

2.为高度限制创建IBOutlet。

 @property (weak, nonatomic) IBOutlet NSLayoutConstraint *txtheightconstraints;

3.不要忘记为你的textview设置委托。

4.

-(void)textViewDidChange:(UITextView *)textView
{
    CGFloat fixedWidth = textView.frame.size.width;
    CGSize newSize = [textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)];
    CGRect newFrame = textView.frame;
    newFrame.size = CGSizeMake(fmaxf(newSize.width, fixedWidth), newSize.height);
    NSLog(@"this is updating height%@",NSStringFromCGSize(newFrame.size));
    [UIView animateWithDuration:0.2 animations:^{
                  _txtheightconstraints.constant=newFrame.size.height;
    }];

}

然后像这样更新你的约束:

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。

这适用于iOS 6.1和iOS 7:

- (void)textViewDidChange:(UITextView *)textView
{
    CGFloat fixedWidth = textView.frame.size.width;
    CGSize newSize = [textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)];
    CGRect newFrame = textView.frame;
    newFrame.size = CGSizeMake(fmaxf(newSize.width, fixedWidth), newSize.height);
    textView.frame = newFrame;
}

或在Swift(适用于Swift 4.1在iOS 11)

let fixedWidth = textView.frame.size.width
let newSize = textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.greatestFiniteMagnitude))
textView.frame.size = CGSize(width: max(newSize.width, fixedWidth), height: newSize.height)

如果你想要支持iOS 6.1，那么你还应该:

textview.scrollEnabled = NO;

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;
}