This is an app I built as part of the interview process for a certain company. This app is written purely in Kotlin and uses Dagger 2 for dependency injection, Android Architecture Components to manage ViewModel lifecycle, and KotlinTest for unit testing. The app is built using MVVM and Data Binding.

• Create an app that shows six numbers (fields) on screen, laid out in two columns.
• Below these fields, a seventh field should show the sum of these six numbers.
• The user can tap on any of the six numbers and edit the number.
• Editing the number should cause the sum to be updated.
• Tapping on the sum should toggle flashing of this field, defined as follows: when flashing, the value should be shown for 500ms, then hidden for 500ms, repeated indefinitely; when not flashing, the value should be visible.
• Please include unit tests.

• Demonstrate at least two different ways of implementing the flashing total, including at least one method not using RxJava.
• Use Dependency Injection to create the ViewModel for the Activity.