There's a lot of todo apps already. I've made this one for myself as an exercise while learning Flutter. It's fun and colourful but features are limited.
The app stores data locally on your machine. No internet connection needed. There's no sync feature at the moment.
Tasks are grouped by categories. First you create a category, then you can add tasks to it.
A task has a name and optional due date. You can mark it as completed whenever you like.
Source code is available at https://github.com/mivoligo/purple_task
Enable snaps on Linux Mint and install Purple Task
Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully.
Snaps are discoverable and installable from the Snap Store, an app store with an audience of millions.
Snap is available for Linux Mint 18.2 (Sonya), Linux Mint 18.3 (Sylvia), Linux Mint 19 (Tara), Linux Mint 19.1 (Tessa) and the latest release, Linux Mint 20 (Ulyana).
You can find out which version of Linux Mint you’re running by opening System info from the Preferences menu.
On Linux Mint 20, /etc/apt/preferences.d/nosnap.pref needs to be removed before Snap can be installed. This can be accomplished from the command line: