I need to read text from an external bluetooth keyboard (an Inateck barcode scanner) on iOS. I'm searching for a solution without using an hidden UITextField like a listener ?
Unfortunately there is no lower-level API to intercept keystrokes on iOS. If your barcode scanner emulates a keyboard (HID Profile) then your only option is to pair it as a keyboard and direct input into a UITextField. This text field can be hidden as you point out.