I built a Flutter paint calculator app — here's what I learned

After releasing a tile calculator app (500+ downloads), I applied the same formula to paint calculation. Tech stack: Flutter + Riverpod (state management) Hive (calculation history) SharedPreferences (settings persistence) Material 3, green #4CAF50 flutter_localizations for i18n Key challenges: Units system — storing metric/imperial per saved calculation was tricky. Each history record saves its own unitSystem so when you load it back, units don't reset to current settings. Opening deductions — supporting both standard sizes (door 2.0×0.9m, window 1.2×1.0m) and custom sizes with separate counters for each type. Paint brand database — auto-filling coverage when a brand is selected while still allowing manual override. The app: Paint Calculator: Room & Wall https://play.google.com/store/apps/details?id=com.paintcalculator.squarefeet.wallroom Happy to answer questions about the Flutter implementation.