This app was mentioned in 5 comments, with an average of 2.60 upvotes
IL Remote is the official phone/tablet controller app for FL. Super easy to use.
Hooks up easily as well. Connect your computer and your mobile device to the same WiFi network, open the app on your phone, then inside FL head to Options -> MIDI Settings and enable "Enable Image-Line Remote" on the bottom-right. FL will detect the app and you'll be able to start using it as a controller. There's an FPC tab you can use for drum pads.
Info page: https://www.image-line.com/support/FLHelp/html/il_remote.htm
App link page on the Play store: https://play.google.com/store/apps/details?id=com.imageline.ILRemote&hl=en
:)
You could try the FL Remote Android App, that's nice to have, but I wouldn't switch to a 24"ish TouchScreenMonitor as my mine.
Greetings (:
\edit:
Image-Line Remote Android (https://play.google.com/store/apps/details?id=com.imageline.ILRemote&hl=en)
Image-Line Remote iOS (https://itunes.apple.com/us/app/ilremote/id777925272?mt=8)
Whats the difference between this and the one that IL made (free): https://play.google.com/store/apps/details?id=com.imageline.ILRemote
There is this for Android. Not sure about iOS.
Sorry, did not try any of them. I only tried Image-Line Remote which is speciffically for FL Studio. It is FREE and GREAT. But i doubt it can be used for another DAW... but maybe it can - try to find out :)
https://www.image-line.com/fl-studio-learning/fl-studio-online-manual/html/il_remote.htm
https://play.google.com/store/apps/details?id=com.imageline.ILRemote&hl=en_US&gl=US