Question

 override func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {

      label.text = textView.text 
      return true;
}

使用此代码，我似乎是一个背后的角色。

Answer 1

shouldChangeTextInRange将被称为之前文本字段的文本值已更改。

尝试将代码改为textViewDidChange：

func textViewDidChange(textView: UITextView) {
    label.text = textView.text
}

Answer 2

您正在设置之前的textView文本。尝试：

 override func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {

      label.text = text 
      return true;
}

因为在传播textView的新文本之前调用此方法。

Answer 3

您可以使用NSString replacingOccurrences(of:with:)来输入文字，例如

<强> Swift2

func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
    let originText = textView.text as NSString
    let replacingText = originText.stringByReplacingCharactersInRange(range, withString: text)

    label.text = replacingText
    return true
}

<强> Swift3

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    let originText = textView.text as NSString
    let replacingText = originText.replacingCharacters(in: range, with: text)

    label.text = replacingText
    return true
}

在UITextView中键入时更新UILabel

3 个答案: