Parking Spot Saver Android App

In mall and office parking lots the failure mode is always the same: you spot a free bay on the map, drive toward it, and someone physically closer takes it. Existing parking apps show availability but can't reserve — the map and the ground truth diverge in the two minutes that matter. SpotHold closes that gap with a hold, not just a map: tapping a free spot locks it for 15 minutes, visible to every other user as "held" so nobody is routed to it. The countdown is honest — arrive before it ends or the spot releases automatically. Check-in on arrival converts the hold into a parked session; a single 10-minute extension covers traffic-light delays. Zones are tiered by walking distance (near elevator vs open deck) with live free counts, so drivers pick their trade-off with open eyes. Fairness is structural: one active hold per user, holds are free, and the history screen records holds kept, completed and expired. The build is Kotlin with a Firebase realtime backend — holds are atomic transactions, and the lot map updates live for everyone.

1. The lot operator maps bays into zones; each bay carries its state (free/held/occupied) in the realtime backend.
2. The driver opens the zone map and sees live free counts per zone plus per-bay states.
3. Tapping a free bay creates a hold as an atomic transaction — the bay flips to "held" for every user instantly.
4. The countdown (15:00) ticks on the spot screen; the driver navigates to the bay.
5. On parking, the driver taps check-in; the hold converts to a parked session.
6. If delayed, the driver uses the single 10-minute extension; at zero the bay auto-releases.
7. The history screen logs the outcome, and the fairness rule blocks a second concurrent hold.

Tech stack:

• Kotlin (Android app language)
• Android Studio (build & layout tooling)
• Firebase Realtime Database (live bay states + hold transactions)
• Firebase Authentication (driver sign-in)
• Material Design 3 components
• MVVM architecture (ViewModel + StateFlow)
• Firebase Cloud Messaging (hold-expiry warnings)
• Git version control

• [Live lot map] Zone-wise bay grid (A/B/C) with free, held and occupied states updating in real time.
• [15-minute spot hold] Tap any free bay to lock it while you drive in — free, with a live countdown.
• [Check-in on arrival] One tap converts the hold into a parked session; the bay shows occupied to others.
• [One-time 10-minute extension] A single extension covers delays; after that the spot releases fairly.
• [Auto-release] Holds expire automatically at zero — no manual cleanup, no permanently "held" bays.
• [Zone tiers] Zones carry walking-distance notes and live free counts (near elevator vs covered vs open deck).
• [Hold history] Every hold recorded: completed, released, expired — with timestamps.
• [Fairness rules] One active hold per user; holds are free so the system can't be gamed by bulk-holding.

• Complete Kotlin Android app source code
• Firebase backend schema and transaction rules (bay states, holds, history)
• Lot map, spot detail, hold timer and history screens as designed
• Check-in / extend / release flows
• Hold-expiry push notifications
• Project report PDF (problem, architecture, transaction design, fairness model, testing)
• PPT presentation for final review
• Viva Q&A preparation document (realtime transactions, countdown UX, FCM)

• The hold is a social contract backed by the map — the app cannot physically block another car from taking the bay; lots pair it with bay signage.
• Bay states need the operator's data feed (manual, sensor or camera); the app does not detect occupancy itself as shipped.
• GPS guidance to the bay is coarse (±5–10 m); in multi-level lots the driver follows level signage.
• Parking fee payment at exit is out of scope — the hold itself is free and payment-agnostic.
• One lot per backend project — multi-lot city networks are future scope.