Personal Diary (LifeLedger) — Android (Java + MVVM + Firebase)

A secure Android diary app built with Java, MVVM, and Firebase. Users can write diary notes for any date, attach files (images/documents/audio/video), search by date/month/tag, and update entries later.

Hard rule: diary notes must never be deleted (enforced by Firestore Security Rules).

Team

• Developer: Girish M B
• College: Dayananda Sagar College of Engineering

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Tech stack

• Language: Java
• Architecture: MVVM (ViewModel + LiveData + Repository)
• UI: Material Design 3 + ViewBinding + RecyclerView
• Backend: Firebase
  • Auth: Email/Password + Google Sign‑In
  • Database: Cloud Firestore
  • Files: Firebase Storage (attachments)
• Min SDK: 24
• Compile/Target SDK: 36
• Build: Gradle Wrapper (8.9) + Android Gradle Plugin (8.7.x)

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Package name (Google Play)

The applicationId (package name) used for Play Store uploads is:

• com.passfamily

Note: Source code package remains com.personaldiary (this is normal; applicationId is what matters for Play Store uniqueness).

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Features

• Auth

  • Email/Password signup + login
  • Strong password policy
  • Forgot password (reset email)
  • Google Sign‑In

• Diary

  • Write for any specific date (future dates disabled in picker)
  • Notes can be empty and still saved/updated
  • Tags: NORMAL, SPECIAL, IMPORTANT, BAD_NEWS
  • Created/Updated timestamps

• Attachments (WhatsApp-style)

  • Attach images, documents, audio, video
  • Upload to Firebase Storage
  • Display as thumbnails / file tiles on:
    • Home screen (current day note)
    • Search results list (Month/Tag)
    • Search by Date result

• Search

  • By Date (view + edit)
  • By Month + Year (read‑only list)
  • By Tag (read‑only list)

• Memories

  • On This Day (1 year ago) card shown on Home screen when a note exists for the same date last year

• Security

  • Users can read/write only their own notes
  • Delete is blocked at Firestore rules level

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App screens

• MainActivity: Welcome screen (Login/Signup + credits)
• LoginActivity: Email/Password login + Google Sign‑In + Forgot Password
• SignupActivity: Registration + Google Sign‑In
• HomeActivity: Create/update note for selected date + attachments + “On This Day”
• SearchActivity: Search by Date/Month/Tag
• MonthNotesActivity: RecyclerView list for Month/Tag results

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Project structure

com.personaldiary
├── activities/
├── adapters/
├── firebase/
├── models/
├── repository/
├── utils/
└── viewmodel/

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Firestore schema

Users

users/{userId}
  name: string
  email: string
  createdAt: timestamp

Diary notes (by date)

Document ID is the date in storage format: yyyy-MM-dd

diary_notes/{userId}/notes/{date}
  content: string
  tag: string
  date: string
  createdAt: timestamp
  updatedAt: timestamp
  attachments: [
    { url: string, name: string, type: string }
  ]

type is one of: image | document | audio | video

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Firebase setup (required)

1) Add Android app in Firebase

Firebase Console → Project Settings → Your Apps → Add app (Android)

• Package name: com.passfamily
• Add SHA‑1 for:
  • Debug keystore (for local testing)
  • Release keystore (for Play Store builds)

Download the generated google-services.json and place it here:

• app/google-services.json

2) Enable Authentication methods

Firebase Console → Authentication → Sign‑in method:

• Enable Email/Password
• Enable Google

3) Enable Firestore

Firebase Console → Firestore Database → Create database
Use Production mode (recommended).

4) Enable Storage (for attachments)

Firebase Console → Storage → Get started

5) Deploy Security Rules

• Firestore Rules: copy/paste firestore.rules into Firestore → Rules → Publish
• Storage Rules: copy/paste storage.rules into Storage → Rules → Publish

Storage rules enforce per-user access under attachments/{userId}/....

6) Indexes

If Firestore asks for indexes (Logcat provides links), create them.

Common queries:

• Month search by date (range + order)
• Tag search by tag

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Build & run

Android Studio

Open the project in Android Studio and press Run.

Command line

./gradlew assembleDebug

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Password policy

Passwords must include:

• Min 8 characters
• At least 1 uppercase letter
• At least 1 number
• At least 1 special character

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Release / Play Store

Build release APK

./gradlew assembleRelease

Build release AAB (Play Store upload)

./gradlew bundleRelease

Upload the generated .aab from:

• app/build/outputs/bundle/release/app-release.aab

Notes

• Package name must be unique on Play Store → this project uses com.passfamily.
• Keep local.properties out of git (it contains machine-specific paths/secrets).

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Non-deletable notes rule

Diary notes must never be deleted. This is enforced by:

• Firestore security rule: allow delete: if false;

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Troubleshooting

• Google Sign‑In fails: make sure SHA‑1 is added in Firebase and the correct google-services.json for com.passfamily is placed in app/.
• Attachments not uploading: ensure Firebase Storage is enabled and storage.rules are published.

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License

Educational project.