1，提示信息
textField.placeholder = "请输入"
2，密文输入
textField.secureTextEntry = true
3，不可被输入
textField.userInteractionEnabled = false
4，限制输入的长度
调用
textField.addTarget(self, action: #selector(self.textDidChangeMax(_:)), forControlEvents: UIControlEvents.EditingChanged)
声明方法
var NumberMax : Int{
return 11
}
func textDidChangeMax(sender:UITextField) {
let lang = textInputMode?.primaryLanguage
if lang == "zh-Hans" {
let range = textField.markedTextRange
if range == nil {
if textField.text?.characters.count >= NumberMax {
textField.text = textField.text?.substringToIndex((textField.text?.startIndex.advancedBy(NumberMax))!)
}
}
}
else {
if textField.text?.characters.count >= NumberMax {
textField.text = textField.text?.substringToIndex((textField.text?.startIndex.advancedBy(NumberMax))!)
}
}
}
