设置“UITextView”和“UITextField”的最大字符数
我想设置允许在UITextView和UITextField键入的最大字符数。 这个号码会显示在一个小标签（供用户参考，Twitter风格）。
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; }
SWIFT 3.01
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.characters.count return numberOfChars < 10 }
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; }
Swift 3.0
只要重写这个UITextFieldDelegate函数，设置所需的characterLimitvariables，你很好去：
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 }
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 <= 70 }
Swift 4 / Xcode 9.1
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool { let currentText = textView.text ?? "" guard let stringRange = Range(range, in: currentText) else { return false } let changedText = currentText.replacingCharacters(in: stringRange, with: text) return changedText.count <= 399 // Pass your character count here }
Swift 4，Xcode 9.1 GM
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool { adjustFrames() return textView.text.count + (text.count - range.length) <= 200 }