In my case with igo keyboard if I haven't powered off, then all I have to do is turn on bluetooth then the keyboard and am set to go.
If I have powered off then I activate bluetooth, turn on keyboard and tap the bluetooth status bar icon, tap bluetooth settings, tap devices, (at this point I will see my keyboard with the key icon next to it, I ignore it) tap edit, select connect and then approve my way back out.
Still a pain but easier than re entering the code.