This is the default Flutter Counter
example app.
The only changes are the addition of configuration files necessary for Flatpak, as follows:
assets/icons/com.example.FlutterApp.svg
-- app's iconpackaging/linux/com.example.FlutterApp.desktop
-- desktop app menu integrationpackaging/linux/com.example.FlutterApp.metainfo.xml
-- AppStream metadata file that contains the information about the app that would be presented on an app store like Flathub
This should be built on an older version on Linux so that it will run on the widest possible set of Linux installations. Recommend docker or a CI pipeline like GitHub actions using the oldest supported Ubuntu LTS.
./build-flutter-app.sh