ios - 当我粘贴文本时，它无法获取文本的高度

Question

当我粘贴文本时，我得到了错误的文本高度。这不算。我只能得到第一行的高度。但是，如果我单击返回键，每行文本如“Software\nis\nawesome”，效果很好。这是代码:

let font = UIFont(name: "HelveticaNeue", size: 18)!
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .center
paragraphStyle.lineSpacing = 8

let textFontAttributes = [
     NSFontAttributeName: font,
     NSForegroundColorAttributeName: UIColor(red: 0.149, green: 0.149, blue: 0.145, alpha: 1.00),
     NSParagraphStyleAttributeName: paragraphStyle
     ] as [String : Any]

let string:NSString = NSString(string: self.txtView.text)
let size:CGSize = string.size(attributes: textFontAttributes)
print("size.height")

但是，当我输入一些文本时，我可以获得正确的文本高度。

如何获得正确的文本高度？

Answer 1

将您的代码放入

    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
       let font = UIFont(name: "HelveticaNeue", size: 18)!
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.alignment = .center
    paragraphStyle.lineSpacing = 8

    let textFontAttributes = [
         NSFontAttributeName: font,
         NSForegroundColorAttributeName: UIColor(red: 0.149, green: 0.149, blue: 0.145, alpha: 1.00),
         NSParagraphStyleAttributeName: paragraphStyle
         ] as [String : Any]

    let string:NSString = NSString(string: self.txtView.text)
    let size:CGSize = string.size(attributes: textFontAttributes)
    print("size.height")
    return true;
 }

您还可以使用

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
      let size = self.textView.sizeThatFits(CGSize(width: width_you_can_afford, height: CGFloat.greatestFiniteMagnitude))
}