State machines keep planes, cars, and medical devices from getting confused about what they are doing. The idea was first used to plan the software inside a fighter jet. These industries trust it with people's lives.

In app development, almost no one uses it. We build drag, resize, and gesture-heavy widgets out of a pile of boolean flags that end up fighting each other, and then we wonder why the bugs are so hard to reproduce.

There is already plenty out there about why state machines are good. This talk is not that. I'll show you how to actually use them in a Flutter app, on the kind of tricky interactions every app eventually needs: telling a tap from a drag, handling two gestures at once, and remembering where you were after switching modes. I'll show it all running live, with the tools I built and have leaned on for the past year.

By the end, you'll know how to use state machines to build even the most complex widget interactions.