I am trying to apply NSAttributedString styles to a UITextField after processing a new text entry, keystroke by keystroke. The problem is that any time I replace the text the cursor will jump the very end on each change. Here's my current approach …
Receive and display text change immediately (same issue applies when I return false and do the text replacement manually)
func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool {
let range:NSRange = NSRange(location: range.location, length: range.length)
let newString = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string);
return true
}
I subscribed to the UITextFieldTextDidChangeNotification notification. This triggers the styling. When the text is changed I replace it (NSString) with the formatted version (NSAttributedString) using some format() function.
func textFieldTextDidChangeNotification(userInfo:NSDictionary) {
var attributedString:NSMutableAttributedString = NSMutableAttributedString(string: fullString)
attributedString = format(textField.text) as NSMutableAttributedString
textField.attributedText = attributedString
}
Styling works fine like this. However after each text replacement the cursor jumps to the end of the string. How can I turn off this behaviour or manually move the cursor back where it started the edit? … or is there a better solution to style the text while editing?
Best Answer
The way to make this work is to grab the location of the cursor, update the field contents, and then replace the cursor to its original position. I'm not sure of the exact equivalent in Swift, but the following is how I would do it in Obj-C.