Some of the things done here will most likely not be necessary on devices that run Wayland.
I had to add this lines to the .desktop file:
I had to add this line to the .apparmor file:
Otherwise I would get this error:
** (process:26446): WARNING **: Unable to exec '/usr/lib/arm-linux-gnueabihf/ubuntu-app-launch/xmir-helper image-and-buttons_0.9.0 ut_session.sh' in '/opt/click.ubuntu.com/.click/users/phablet/image-and-buttons': Permission denied
I had to export this variable to get bigger buttons/text/entries...:
To get an on screen keyboard I installed this packages on my device:
...and exported this variable:
I reply to this old post, because when I searched for a solution, this was one of the first things that came up and I could not find any working examples my self.
Maybe someone will find this helpful or will tell me if my app and my solution also work on other devices.