设置`UITextView`和`UITextField`的最大字符数

Question

我想在a UITextView和a中设置允许输入的最大字符数UITextField.这个数字将以小标签显示(供用户参考,Twitter风格).

Answer 1

更新Swift 4.X

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
    let numberOfChars = newText.count
    return numberOfChars < 10    // 10 Limit Value
}

试试这个:

func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
    let newText = (textView.text as NSString).stringByReplacingCharactersInRange(range, withString: text)
    let numberOfChars = newText.characters.count // for Swift use count(newText)
    return numberOfChars < 10;
}

Answer 2

SWIFT 4

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
     let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
     return newText.count < 10
}

Answer 3

斯威夫特4:

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
  let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
  return newText.count <= 70
}

Answer 4

试试这个: -

 func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
    print("chars \(textView.text.characters.count) \( text)")

    if(textView.text.characters.count > 20 && range.length == 0) {
        print("Please summarize in 20 characters or less")
        return false;
    }

    return true;
}

Answer 5

Swift 3.0

只需覆盖这个UITextFieldDelegate函数,设置所需的characterLimit变量就可以了:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool 
{        
        let characterLimit = 5
        let newText = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
        let numberOfChars = newText.characters.count
        return numberOfChars < characterLimit
}

Answer 6

Swift 5 更新

给出最前沿的结果

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    return range.location < 140 // limit to 140 chars
}