UISearchController does not recognise umlaut, Swift, iOS

Question

I have a search function in my app but it does not recognise any umlaut (ä,ö,ü). I use UISearchController. How do I adjust the code that it recognises umlaut?

($0.title as AnyObject).contains(self.searchController.searchBar.text!.lowercased())

Answer 1

This works fine for me. I would sanity check your strings in lldb.

  func search() {
    let stringWithDiaeresis = "Reënter"
    let stringWithoutDiaeresis = "Reenter"
    let searchStringWithDiaeresis = "Reë"
    let searchStringWithoutDiaeresis = "Ree"

    if stringWithDiaeresis.contains(searchStringWithDiaeresis) {
      print("Range of Reë detected in Reënter")
    }

    if stringWithDiaeresis.contains(searchStringWithoutDiaeresis) {
      print("Range of Reë detected in Reenter")
    }

    if stringWithoutDiaeresis.contains(searchStringWithDiaeresis) {
      print("Range of Reë detected in Reenter")
    }

    if stringWithoutDiaeresis.contains(searchStringWithoutDiaeresis) {
      print("Range of Ree detected in Reenter")
    }

    /* Prints the following:
     Range of Reë detected in Reënter
     Range of Ree detected in Reenter
     */

    if (stringWithDiaeresis as AnyObject).contains(searchStringWithDiaeresis) {
      print("Reënter contains Reë")
    }

    if (stringWithDiaeresis as AnyObject).contains(searchStringWithoutDiaeresis) {
      print("Reënter contains Ree")
    }

    if (stringWithoutDiaeresis as AnyObject).contains(searchStringWithDiaeresis) {
      print("Reenter contains Reë")
    }

    if (stringWithoutDiaeresis as AnyObject).contains(searchStringWithoutDiaeresis) {
      print("Reenter contains Ree")
    }

    /* Prints the following:
     Reënter contains Reë
     Reenter contains Ree
     */
  }

If your intention is to match strings with diacritics to those without, you're going to need to sanitize your data and remove diacritics from everything.

E.g.

if stringWithDiaeresis.localizedStandardContains(searchStringWithoutDiaeresis) {
  print("Reënter contains Ree")
}

/* Prints the following:
 Reënter contains Ree
 */

The moral of the story here is that you really ought to be using the specialized/more sophisticated methods available to String types instead of generic contains().