extension LUserInfoEditCtrl: UITextFieldDelegate,YYTextViewDelegate {
    
    //限制TF開頭不能輸入空格
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if string == " " {
            return false
        }
        return true
    }
    
    @objc func tfDidChange(textField: UITextField) {
        let maxLength = 10
        let toBeString : String = textField.text ?? ""
        let lang = textField.textInputMode?.primaryLanguage
        if lang == "zh-Hans" {
            //簡體中文輸入

            //獲取高亮部分
            let selRange = textField.markedTextRange
            let position = textField.position(from: selRange!.start, offset: 0)

            //沒有高亮選擇的字就缆，則對已輸入的文字進行字數(shù)統(tǒng)計和限制
            if (position == nil) {
                if toBeString.count > maxLength {
                    textField.text = String(toBeString.prefix(maxLength))
                }
            }

        }else {
            //中文輸入法以外的直接對其統(tǒng)計限制即可制跟，不考慮其他語種情況
            if toBeString.count > maxLength {
                let aaa = toBeString as NSString
                let rangeIndex = aaa.rangeOfComposedCharacterSequence(at: maxLength)
                if rangeIndex.length == 1 {
                    textField.text = String(toBeString.prefix(maxLength))
                }else {
                    let rangeRange = aaa.rangeOfComposedCharacterSequences(for: NSMakeRange(0, maxLength))
                    textField.text = aaa.substring(with: rangeRange)
                }
            }
        }
        
        nameCountLab.text = "\(textField.text?.count ?? 0)/10"
    }
    
    
    func textViewDidChangeSelection(_ textView: YYTextView) {
        let num = textView.text.count
        let maxLength = 50
        if num > maxLength {
            textView.text = String(textView.text.prefix(maxLength))
        }
        
        infoCountLab.text = "\(num)/\(maxLength)"
    }
    
    
}

限制輸入小數(shù)點后保留兩位小數(shù)

func textField(_ textField:UITextField, shouldChangeCharactersIn range:NSRange, replacementString string:String) ->Bool{
        if string.length==0{
            return true
        }
        //第一個參數(shù)竭贩，被替換字符串的range
        //第二個參數(shù)旧困，即將鍵入或者粘貼的string
        //返回的是改變過后的新str印屁，即textfield的新的文本內(nèi)容
        let checkStr = (textField.text as NSString?)?.replacingCharacters(in: range, with: string)
        //正則表達式（只支持兩位小數(shù)）
        let regex = "^\\-?([1-9]\\d*|0)(\\.\\d{0,2})?$"
        //判斷新的文本內(nèi)容是否符合要求
        return self.isValid(checkStr: checkStr!, regex: regex)
    }
    //檢測改變過的文本是否匹配正則表達式循捺，如果匹配表示可以鍵入，否則不能鍵入
    func isValid(checkStr:String, regex:String) ->Bool{
        let predicte = NSPredicate(format:"SELF MATCHES %@", regex)
        return predicte.evaluate(with: checkStr)
    }