Most USB MIDI controllers don’t need software drivers in order to use them. You just plug them in and they work.
Unfortunately a small number of older USB MIDI controllers like the NI Traktor Kontrol F1, and the Novation Launchpad (version 1) need drivers. iOS and Android don’t support USB MIDI controllers that need drivers. So you can’t use them on iOS or Android.
There is literally nothing I can do about it, except for perhaps, breaking in to Native Instruments, stealing their driver code, then breaking into Google and Apple offices to insert the native instruments code into the iOS and Android operating systems and hope no-one discovers it.
Very sorry about that (but it’s not my fault!)