Otter is an application that demonstrates fundamental Android development principles. This project is designed to be accessible to beginners to Android with Java experience, and to showcase Android best practices with minimal dependencies.

• Model-View-ViewModel architecture
• Android Architecture Components:
  • ViewModel
  • Room
  • LiveData
• Android components:
  • Activities
  • Fragments
  • Services
  • Broadcast Receivers
• CoordinatorLayout
• Repository pattern

Otter uses a Model-View-ViewModel architecture (MVVM). MainActivity is the main entry point to the application; its only concern is serving fragments and handling fragment callbacks. AlarmFragment displays a LiveData list of alarms provided by AlarmViewModel. The viewmodel fetches the user's alarms from AlarmRepository, which provides an interface to the database via Room.

When the FAB in AlarmFragment is pressed, fragments are queued to display various dialogs to create a new alarm object. When a fragment is destroyed, a callback is sent to MainActivity to manage the alarm object and pass data between fragments. When the object is created, the viewmodel is updated with the new data, which also creates a new system alarm in BroadcastRepository using the alarm's data.

AlarmBroadcastRepository listens for updates to system alarms, and calls NotificationService to display a notification when one occurs. ActionReceiver allows the notification to perform actions to snooze and dismiss alarms. OnBootReceiver and AlarmReinitWorker work together to restore system alarms when the device is rebooted.

AlarmActivity acts as a secondary entry point to the application, and is activated by clicking an alarm notification. It displays data from the provided alarm, and can perform actions to snooze and dismiss as well. Exiting the activity returns the user to MainActivity.

• Move responsibility of fragment callbacks to AlarmFragment

• Bug reports and contributions are always welcome. Please use this guide when making a PR:
  • Add an issue in the tracker linked to the PR
  • New features should match the existing style, including use of Java and minimal external dependencies