📱 Modern Todo App

A feature-rich, native Android todo application built with Kotlin and Room Database, following clean architecture principles and modern Android development practices.

🎯 Features

📋 Core Functionality

• ✅ Create, Edit, Delete todos with comprehensive form validation
• 🎯 Priority levels (High/Medium/Low) with color-coded visual indicators
• 📅 Due date & time management with date/time pickers
• 🔔 Smart reminders with notification scheduling using AlarmManager
• ✏️ Rich text descriptions with multi-line support

🔍 Advanced Search & Filtering

• 🔎 Real-time search across todo titles with instant results
• 📊 Multiple sorting options:
  • Newest First (default)
  • Priority-based sorting
  • Due date sorting (earliest/latest)
• 🎛️ Intuitive toolbar controls with search bar integration

⚠️ Smart Overdue Detection

• 🚨 Visual indicators for overdue tasks with warning icons
• 📊 Dynamic date formatting showing days overdue
• 🎨 Color-coded urgency (red text for overdue items)

✅ Completed Todos Management

• 📜 Dedicated completed todos view with distinct styling
• 🎬 Smooth slide animations when marking todos as incomplete
• 🎨 Visual differentiation (strikethrough text, muted colors, transparency)
• ↩️ One-tap reactivation to move todos back to active list

⚙️ Settings & Data Management

• 📊 App statistics (total, active, completed todos, completion rate)
• 🗑️ Bulk operations:
  • Clear all todos
  • Clear completed todos only
  • Clear all scheduled reminders
• 📋 Comprehensive app information

🏗️ Technical Architecture

MVVM Architecture Pattern

UI Layer (Activities/Fragments)
    ↓
ViewModel Layer (State Management)
    ↓
Domain Layer (Business Logic)
    ↓
Repository Layer (Data Abstraction)
    ↓
Data Layer (Room Database)

Technology Stack

• Language: Kotlin 100%
• Database: Room Persistence Library
• Architecture: MVVM with LiveData/StateFlow
• UI: Material Design 3 components
• Async: Coroutines + Flow for reactive programming
• DI: Manual dependency injection (ViewModelFactory pattern)
• Notifications: AlarmManager + NotificationManager

Key Technical Decisions

Reactive Data Flow

Room Database → Flow<List<Todo>> → ViewModel → StateFlow → UI Updates

• Real-time UI updates using Kotlin Flows
• Automatic data synchronization across screens
• No manual refresh needed

State Management

data class TodoViewUiState(
    val isLoading: Boolean = false,
    val todos: List<Todo> = emptyList(),
    val searchQuery: String = "",
    val isSearchActive: Boolean = false,
    val currentSortOption: SortOption = SortOption.CREATED_DESC
)

Database Schema

@Entity(tableName = "todos")
data class Todo(
    @PrimaryKey(autoGenerate = true)
    var id: Long = 0L,
    val title: String,
    val description: String,
    val priority: Priority,
    val dueDate: LocalDateTime,
    val reminderDateTime: LocalDateTime? = null,
    val isCompleted: Boolean = false
)

📸 Screenshots

Main Screen	Completed Todos	Add Todo	Sort Options

The app features a clean, Material Design interface with intuitive navigation and visual feedback

🎨 UI/UX Highlights

Material Design Implementation

• 🎨 Consistent color scheme with priority-based card backgrounds
• 📱 Responsive layouts using ConstraintLayout and CardView
• ✨ Smooth animations for state transitions and user interactions
• 🔄 Loading states with progress indicators

User Experience Features

• 🎯 One-handed usage with bottom-positioned FAB
• ⚡ Instant feedback with toast messages and visual confirmations
• 🔒 Confirmation dialogs for destructive actions
• 📱 Proper keyboard handling in search mode

🔧 Advanced Features

Smart Reminder System

• ⏰ Precise timing using AlarmManager for exact notifications
• 🔔 Permission handling for Android 13+ notification permissions
• 🎯 Automatic cancellation when todos are completed or deleted

Search Implementation

• 🔍 Database-level filtering using Room SQL queries
• ⚡ Debounced input to prevent excessive database calls
• 🎛️ Clean state management with search activation/deactivation

Data Persistence

• 💾 Robust error handling with Result wrapper pattern
• 🔄 Automatic data validation at multiple layers
• 📊 Efficient queries with proper indexing

🚀 Getting Started

Prerequisites

• Android Studio Arctic Fox or later
• Android SDK 24+ (Android 7.0)
• Kotlin 1.8+

Installation

# Clone the repository
git clone https://github.com/yourusername/todo-app.git

# Open in Android Studio
cd todo-app
# File -> Open -> Select project folder

# Build and run
./gradlew assembleDebug

Key Dependencies

// Room Database
implementation "androidx.room:room-runtime:2.5.0"
implementation "androidx.room:room-ktx:2.5.0"

// Coroutines & Flow
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3"

// Lifecycle & ViewModel
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.7.0"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.7.0"

// Material Design
implementation "com.google.android.material:material:1.9.0"

🔮 Future Enhancements

• 📊 Data Export/Import (CSV, JSON)
• 🌙 Dark Mode support
• 📱 Widget for home screen
• 🔄 Cloud Sync with Firebase
• 📈 Analytics and productivity insights
• 🎨 Custom themes and color schemes

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

👨‍💻 Developer

Saptarshi Das

• 📧 Email: saptarshidas0101@gmail.com
• 💼 LinkedIn: Saptarshi Das
• 🐱 GitHub: @babatezpur

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Built with ❤️ using modern Android development practices