Small moments. Steady momentum.
An Android wellness app that makes self-care approachable by keeping it small.
Sub-minute breathing check-ins · mood tracking with on-device insights · guided journaling · home-screen widgets
A 67-second tour: breathing check-ins, gentle gamification, mood insights, the buddy nudge and the architecture behind it.
mellow-app-tour.mp4
Instead of long meditation sessions or complex habit trackers, Mellow focuses on micro check-ins — guided breathing that takes under a minute — paired with a coin-based reward system, mood journaling, and an optional buddy system.
The philosophy: consistency matters more than intensity. A 30-second breathing exercise done daily builds more resilience than an hour-long session done once a month. Mellow reinforces that with streaks, a forgiving grace period, and a coin jar that fills over time.
The full design system — palette, typography, iconography, mascot, and every screen — is documented as an interactive page:
👉 design/index.html — open in a browser
| Page | What's inside |
|---|---|
design/index.html |
Design system + every screen (start here) |
design/mellow_screens.html |
Full-app screen concepts, light & dark |
design/mellow_innovative.html |
Circle, duo bonds, rewards hub, reflections |
design/mellow_journal_buddies.html |
Journal & buddies concepts with Sprout |
design/mellow_redesign.html |
The original redesign direction |
Every mood in the app — calendar cells, journal entries, charts, widgets — resolves to one of five colours.
| Depressed | Sad | Neutral | Happy | Overjoyed | |
|---|---|---|---|---|---|
| Hex | #A694F5 |
#ED7E1C |
#AEA194 |
#FFCE5C |
#9BB068 |
Fraunces (serif display) + Plus Jakarta Sans (UI), both bundled as static weights in res/font so exact weights render on every API level — no faux-bold, no platform fallback.
The mascot — a calm meditating seedling, built as an Android VectorDrawable (no external art, no Lottie). Appears in the breathing orb, the journal prompt, and empty states.
Five steps — welcome, name, age (a snapping wheel picker), the things that make you happy (a searchable tag cloud), and goals — with a shared progress bar, back and skip.
Home leads with the coin jar, streak and today's tools. The check-in runs four breaths automatically — the screen fills with a soft fluid wave as you breathe, with Sprout in the orb.
Three tabs — List, Calendar (a face per day, backdate any past day) and Overview (a smooth spline across 1 Day → All Time, plus a packed bubble chart sized by how often each mood was logged).
| Widget | Size | What it does |
|---|---|---|
| Mellow — Mood | 4×2 | Log today's mood in one tap, without opening the app |
| Mellow — Mood Stats | 4×4 | Positive/negative bars for the last fortnight + the last 7 days as faces |
Both read through the app's repository layer via a Hilt EntryPoint, so the one-mood-per-day rule and coin rewards behave exactly as they do in-app. The stats chart is drawn to a bitmap, since RemoteViews can't host custom views.
Guided breathing check-ins — four breaths, auto-advancing, with a fluid fill that rises and settles with each breath. Awards coins on completion.
CheckInActivity · WaveView · GamificationEngine
Coin & jar reward system — coins accumulate in a jar with a randomised capacity. Fill it and a reward triggers, then the jar resets.
GamificationEngine · UserProgress · RewardActivity
Soft streaks with a grace period — missing a single day doesn't break your streak; a one-time grace absorbs the gap. Longest streak is always preserved.
GamificationEngine.calculateStreakUpdate() · DateUtils
Mood tracking + on-device intelligence — month and year trends, direction vs. the previous period, your strongest weekday, and a journaling correlation. All computed locally from mood logs merged with journal moods — no backend, works offline.
MoodInsights · MoodOverview · MoodAnalytics
Journaling — a daily prompt, mood per entry, backdating, and an insight strip (entries, journaling streak, dominant mood).
JournalHistoryActivity · JournalRepository
Buddies — send requests, connect, and nudge a buddy with a haptic buzz.
BuddyActivity · BuddyRepository
The nudge, a social cue for the habit: long-press a buddy's card and their phone buzzes in real time through a Firestore snapshot listener. Three distinct haptic patterns confirm the press, the send, and the arrival. The nudge is the cue, the 30-second check-in is the routine, coins and a kept streak are the reward, and tomorrow you nudge them back.
BuddyViewModel · VibrationHelper
MVVM, Java, with a clean separation between UI, domain and data.
mellow/
├── data/
│ ├── model/ MoodEntry, JournalEntry, UserProgress, BuddyGroup, …
│ ├── repository/ interfaces + Firestore implementations
│ ├── mapper/ Firestore ⇄ model
│ └── util/ DateUtils, MellowResult, VibrationHelper
├── domain/
│ ├── engine/ GamificationEngine — pure streak + coin logic
│ └── analytics/ MoodAnalytics, MoodInsights, MoodOverview
├── ui/ auth, onboarding, mood, journal, buddy, profile, progress
└── widget/ home-screen widgets
The domain layer is deliberately pure — no Android, no Firebase, all static methods — so the streak, coin and analytics logic is trivially testable.
Stack: Java · Gradle 8.13 · compileSdk 36, minSdk 26 · Firebase Auth + Firestore (offline persistence on) · Hilt · Lifecycle ViewModel/LiveData · ViewPager2 · custom Canvas views for every chart
git clone https://github.com/ayushvarma7/Mellow.git
cd Mellow- Create a Firebase project and add an Android app using the
applicationIdfromapp/build.gradle - Enable Authentication (Google + Anonymous) and Cloud Firestore
- Download
google-services.jsonintoapp/ - Add your SHA-1 to the Firebase project for Google Sign-In
- Build:
./gradlew assembleDebug
google-services.jsonis gitignored — the build will fail without it.
Ayush Varma
Built for academic purposes as part of CS5520 at Northeastern University.