swift 获取和设置textview光标位置

指定UITextViewDelegate

var prev_idx:UITextRange?
func textViewDidChange(_ textView: UITextView) {
            prev_idx = textView.selectedTextRange //保存当前光标
            textView.selectedTextRange = prev_idx // 重置光标
}
func textViewDidChangeSelection(_ textView: UITextView) {
        print("光标移动时 选择范围发生变化")
}