Water Reminder is a full-featured, beautifully designed Android application that helps users stay properly hydrated throughout the day. The app combines a smart, science-backed goal recommendation engine with flexible reminder scheduling, animated circular progress, a home-screen widget, and a rich statistics screen — all packaged in clean, maintainable Java code following Google’s recommended MVVM architecture.

Upon first launch, users are guided through a smooth onboarding flow that collects their name, gender, age, weight, height, activity level, and local weather conditions. The app then calculates a personalised daily water intake goal in real time using an evidence-based formula and lets the user fine-tune it with a slider before saving.

The main dashboard presents a large animated circular progress ring showing how much of the daily goal has been reached, a horizontal scrollable container picker (glass, cup, bottle, mug, flask, custom), a live log of every drink recorded today with swipe-to-delete, a streak card showing consecutive days of goal completion, and a motivational message that updates dynamically throughout the day.

The Reminders screen lets users both manually create individual alarms (with custom label, time, and amount) and auto-generate a full schedule derived from their saved wake-up time, bedtime, and preferred interval — a powerful one-tap setup that eliminates tedious manual entry. All alarms survive device reboots via a BootReceiver and are delivered as high-priority notifications with inline Drink Now and Skip action buttons that log or dismiss the entry without opening the app.

The History screen shows interactive bar charts (via MPAndroidChart) for weekly, monthly, and yearly periods, with goal-achieved bars highlighted in a distinct colour and summary statistics (average, maximum, minimum, and total intake) shown below the chart.

A home-screen widget shows the current intake, goal, percentage progress bar, and a one-tap Drink button — all updated in real time from the Room database without opening the app.

Data safety is covered by a JSON-based backup and restore system that exports all records to the device’s external storage with a timestamped filename, and imports them back with a single file picker. An optional automated backup can be scheduled via WorkManager. The app also sends an end-of-day summary notification and a goal-achieved celebration notification with confetti vibration pattern.

The codebase is clean, fully commented, and ready for immediate branding — just replace the package name, launcher icons, AdMob IDs, and colour palette in a few minutes.

Home Dashboard

Animated circular progress ring with smooth value interpolation (800 ms animator)
Real-time intake display in ml or fl oz depending on user preference
Motivational message that dynamically reflects current hydration status
Drink count badge and today’s intake log (RecyclerView with DiffUtil)
Horizontal container picker — Glass, Cup, Bottle, Mug, Flask, and Custom
FAB (Floating Action Button) to instantly log the selected container volume
Custom-amount dialog accepting any value from 1–2000 ml
Undo last drink via Snackbar action or dedicated button
Streak counter displaying consecutive days with completed goals
Pull-to-refresh for streak recalculation
Quick navigation to Settings and History

⏰ Smart Reminders

Create unlimited individual reminders with custom time, label, and drink amount
Auto-generate a full reminder schedule from wake time, bedtime, and interval
Enable/disable each reminder individually via toggle switch
High-priority notifications with Drink Now and Skip inline action buttons
Logging a drink directly from the notification updates app data in the background
Exact alarm scheduling (AlarmManager.setExactAndAllowWhileIdle) for reliable delivery
Alarms rescheduled automatically after device reboot via BootReceiver
Alarms rescheduled automatically after app update via MY_PACKAGE_REPLACED
Foreground service for reliable reminder delivery on strict battery-saver devices
Separate clear buttons for auto-generated and manually created reminders
Custom notification sound — pick any audio file from the device or reset to default
Three dedicated notification channels: Reminders, Goal Achieved, Daily Summary

History & Statistics

Interactive bar chart (MPAndroidChart) with animated entry
Weekly, Monthly, and Yearly tabs for flexible time-range switching
Goal-achieved bars highlighted in a distinct accent colour
Summary cards: Average, Maximum, Minimum, and Total intake for the selected period
All values honour the user’s ml / fl oz unit preference

User Profile & Goal Engine

Collects name, gender, age, weight, height, activity level, and weather condition
Real-time personalised goal calculation using a science-based formula (weight × 35 ml base, adjusted for activity, gender, weather, and age)
Goal slider (500–5000 ml, step 50 ml) with live label and recommended value display
Configurable wake-up time, bedtime, and reminder interval
Optional profile photo from device gallery
ml / fl oz unit toggle with automatic conversion throughout the entire app
Profile data persisted in Room database as a singleton row

Shows current intake, daily goal, percentage progress bar, and percentage text
One-tap Drink button logs the configurable widget drink amount directly
Widget drink amount configurable via a slider in Settings (e.g., 150–500 ml)
Tapping the widget body opens the main app
Updates itself after every logged drink

⚙️ Settings

Light / Dark / System theme selection (applied instantly, no restart required)
In-app language switcher (English, German, Spanish, French, Hindi) — full app restart for instant locale change
Custom notification sound picker with reset-to-default option
Manual JSON backup with timestamped filename saved to external storage
One-tap JSON restore from any file picker-accessible location
Automatic backup toggle (WorkManager periodic task)
Widget default drink amount slider
Edit profile shortcut
Clear all water intake data with confirmation dialog
Last backup timestamp displayed

Monetisation

Google AdMob SDK integrated and initialised at application startup
AdMob App ID configurable in AndroidManifest.xml — swap one line to go live
Ad placement slots ready to add banner/interstitial/rewarded ads as needed

️ Architecture & Code Quality

MVVM architecture with Android Jetpack ViewModel and LiveData
Room database with three DAOs: WaterIntake, Reminder, UserProfile
Repository pattern separating data layer from ViewModels
View Binding throughout — no findViewById calls
WorkManager for recurring daily summary and auto-backup tasks
Dedicated executor thread for all database I/O
Clean package structure: activities, fragments, adapter, database, model, receiver, repository, service, utils, viewmodel, widget, worker
All strings externalised and localised — easy to add new languages
Fully commented, readable Java code

Requirements

Requirement	Details
Language	Java (Android)
Minimum Android SDK	Android 6.0 Marshmallow (API 23)
Target / Compile SDK	Android 14 (API 34)
Build System	Gradle 8.4 with Android Gradle Plugin
IDE	Android Studio Hedgehog or newer (any version supporting Gradle 8.x)
Java Version	Java 8 (sourceCompatibility / targetCompatibility)
Internet	Required for AdMob initialisation; all other features work fully offline
Permissions	`RECEIVE_BOOT_COMPLETED`, `SCHEDULE_EXACT_ALARM`, `USE_EXACT_ALARM`, `POST_NOTIFICATIONS` (Android 13+), `VIBRATE`, `FOREGROUND_SERVICE`, `INTERNET`, `ACCESS_NETWORK_STATE`, `READ_EXTERNAL_STORAGE` (≤ API 32), `WRITE_EXTERNAL_STORAGE` (≤ API 29), `READ_MEDIA_IMAGES` (API 33+)
Key Libraries	Room (database), Lifecycle ViewModel & LiveData, WorkManager, Navigation Component, MPAndroidChart (bar charts), Google AdMob, Material Components, CircularProgressIndicator, AndroidX AppCompat, RecyclerView, DataBinding, ConstraintLayout
AdMob	A valid AdMob App ID must be added to `AndroidManifest.xml` before publishing (test ID is included in the source)
Keystore	A release keystore is required to sign the APK / AAB for Play Store distribution

Instructions

1. Open the Project

Unzip the downloaded archive to a local folder.
Launch Android Studio and choose File → Open.
Select the root WaterReminderApp/ folder (the one containing settings.gradle).
Wait for Gradle sync to finish and all dependencies to download.

2. Rebrand the App (Optional)

Package name: Right-click the com.waterreminder.app package in the Project pane → Refactor → Rename to your own package (e.g., com.yourcompany.hydrate). Also update applicationId in app/build.gradle.
App name: Edit app_name in res/values/strings.xml (and all values-XX folders).
Launcher icons: Replace all ic_launcher / ic_launcher_round files in the mipmap-* folders, or use File → New → Image Asset in Android Studio.
Colours: Edit res/values/colors.xml — change colorPrimary and colorSecondary to match your brand palette.

3. Configure AdMob

Open AndroidManifest.xml and replace the test AdMob App ID value (ca-app-pub-3940256099942544~3347511713) with your own real App ID from the AdMob console.
Add your ad unit IDs wherever you place banner, interstitial, or rewarded ad views in the layouts and activities.

4. Add / Remove Languages

The app ships with English (default), German (values-de), Spanish (values-es), French (values-fr), and Hindi (values-hi).
To add a new language, create a new values-XX folder (e.g., values-pt) and copy strings.xml from values/, then translate all values.
Add the language display name and BCP-47 code to res/values/arrays.xml (arrays language_options and language_codes).
To remove a language, delete its values-XX folder and remove its entry from the arrays.

5. Customise Containers

Container types, icons, and default volumes are defined in ContainerHelper.java.
Add or remove container entries and pair them with vector drawables in res/drawable/.

6. Build & Run

Debug: Connect an Android device (API 23+) or start an emulator, then click Run ▶ in Android Studio.
Release APK / AAB: Go to Build → Generate Signed Bundle / APK, provide your keystore, and follow the wizard. Upload the resulting .aab to the Google Play Console.

7. Notification Permissions (Android 13+)

On Android 13 (API 33) and above, the app requests the POST_NOTIFICATIONS runtime permission. The request is triggered automatically; users must grant it for reminders to appear.
On Android 12+ (API 31+), the SCHEDULE_EXACT_ALARM permission may also require the user to enable it manually via Settings → Apps → Special app access → Alarms & reminders. The app handles this gracefully.

8. Backup & Restore

Tap Settings → Backup Now to export a timestamped JSON file to <external storage>/Android/data/<package>/files/WaterReminder/.
Tap Settings → Restore Backup and select a previously exported .json file to restore all records.
Enable Auto Backup to schedule a periodic background backup via WorkManager.

APK: https://www.mediafire.com/file/dvxikdy4oy2ggde/waterreminderav.apk/file

Water Reminder – Daily Hydration Tracker & Smart Alarm App for Android