Countdown Timer

A simple Android Timer app in Kotlin, which allows users to set a countdown timer, start/pause/stop it, and adjust the timer dynamically.

Design Principles and Architecture

• Fragments: The app uses multiple fragments (FragmentForm for input and FragmentMain for displaying and controlling the countdown) to promote a modular design, which allows for better reuse and maintainability.
• Object-Oriented Design: The app follows object-oriented principles like encapsulation, where the CountdownTimerManager class encapsulates all the timer-related logic. It also employs separation of concerns by keeping the UI logic separate from the business logic, ensuring the app is modular and easier to extend or maintain.

Components

• MainActivity: Initializes the app and displays the FragmentForm.
• FragmentForm: UI to set timer duration in minutes and seconds.
• FragmentMain: Displays the timer and allows controls for starting, pausing, stopping, and adjusting time.
• CountdownTimerManager: Handles all the timer logic - start, pause, stop, adjust time.

Key Features

• Set Timer: Input minutes and seconds.
• Start/Pause/Stop: Control the countdown.
• Dynamically Adjust Time: Add or subtract time in predefined increments.
• Notifications: Alarm and toast when time is up.

Preview