Swift 估计某些文本的UICollectionView单元格的大小

因此，我正在创建一个消息类型的应用程序，它由一些包含不同长度文本的

UITextView

块组成，这些块位于一个“气泡”中

UIView

let textView: UITextView = {
    let text = UITextView()
    text.text = "SAMPLE"
    text.translatesAutoresizingMaskIntoConstraints = false
    text.backgroundColor = .clear
    text.textColor = .white
    return text
}()
let bubbleView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(r: 0, g: 137, b: 247)
    view.layer.cornerRadius = 14
    view.layer.masksToBounds = true
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()
var bubbleWidthAnchor: NSLayoutConstraint?

    bubbleView.rightAnchor.constraint(equalTo: self.rightAnchor, constant: -8).isActive = true
    bubbleView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    bubbleWidthAnchor = bubbleView.widthAnchor.constraint(equalToConstant: 250)
    bubbleWidthAnchor?.isActive = true
    bubbleView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true

    textView.leftAnchor.constraint(equalTo: bubbleView.leftAnchor, constant: 8).isActive = true
    textView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    textView.rightAnchor.constraint(equalTo: bubbleView.rightAnchor).isActive = true
    textView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true

为了设置单元格的高度，我使用了一个自定义函数，该函数应该不能正常工作

自定义功能：

private func estimatedFrameForText(text: String) -> CGRect {
    let size = CGSize(width: 250, height: 250)
    let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)

    return NSString(string: text).boundingRect(with: size, options: options, attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 16)], context: nil)
}

我在

UICollectionView

的

sizeForItemAt

函数中调用它：

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    var height: CGFloat = 80 //Arbitrary number
    if let text = messages[indexPath.item].text {
        height = estimatedFrameForText(text: text).height + 8
    }
    return CGSize(width: view.frame.width, height: height)
}

我遇到的一个简单问题是。。。它不太管用：

---

你知道我哪里出错了吗，或者根据文本获得我需要的单元格估计大小的更好解决方案吗？

事实证明，我所缺少的只是在

文本视图中设置文本大小

let textView: UITextView = {
    let text = UITextView()
    text.text = "SAMPLE"
    text.translatesAutoresizingMaskIntoConstraints = false
    text.backgroundColor = .clear
    text.textColor = .white
    return text
}()
let bubbleView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(r: 0, g: 137, b: 247)
    view.layer.cornerRadius = 14
    view.layer.masksToBounds = true
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()
var bubbleWidthAnchor: NSLayoutConstraint?

    bubbleView.rightAnchor.constraint(equalTo: self.rightAnchor, constant: -8).isActive = true
    bubbleView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    bubbleWidthAnchor = bubbleView.widthAnchor.constraint(equalToConstant: 250)
    bubbleWidthAnchor?.isActive = true
    bubbleView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true

    textView.leftAnchor.constraint(equalTo: bubbleView.leftAnchor, constant: 8).isActive = true
    textView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    textView.rightAnchor.constraint(equalTo: bubbleView.rightAnchor).isActive = true
    textView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true

需要将
text.font=UIFont.systemFont（of大小：16）
放入，因为获取估计大小的函数具有：

attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 16)

因此，您必须将两者定义为相同。
Swift 4.2更新后的答案是在uilabel的基础上处理uicollectionviewCell的高度和宽度

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
{
  let size = (self.FILTERTitles[indexPath.row] as NSString).size(withAttributes: [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 14.0)])
    return CGSize(width: size.width + 38.0, height: size.height + 25.0)


}