Background

The goal of this project is to convert a simple Java stopwatch to an Android application. The original java code can be found here.

Learning Objectives

Modeling

• Modeling state-dependent behavior with state machine diagrams (see also here)
• Distinguishing between view states and (behavioral) model states

Semantics

• Event-driven/asynchronous program execution
• User-triggered input events
• Internal events from background timers
• Concurrency issues: single-thread rule of accessing/updating the view in the GUI thread

Architecture and Design

• Key architectural issues and patterns
  • Simple dependency injection (DI)
  • Model-view-adapter (MVA) architectural pattern
  • Mapping MVA to Android
  • Difference between MVA and model-view-controller (MVC)
  • Distinguishing among dumb, reactive, and autonomous model components
• Key design patterns
  • Implementing event-driven behavior using the Observer pattern
  • Implementing state-dependent behavior using the State pattern
  • Command pattern for representing tasks as objects
  • Façade pattern for hiding complexity in the model from the adapter
• Relevant class-level design principles
  • Dependency Inversion Principle (DIP)
  • Single Responsibility Principle (SRP)
  • Interface Segregation Principle (ISP)
• Package-level architecture and relevant principles
  • Dependency graph (see also here)
  • Stable Dependencies Principle (SDP)
  • Acyclic Dependencies Principle (ADP)
• Architectural journey

Testing

• Different types of testing
  • Component-level unit testing
  • System testing
  • Instrumentation testing
• Mock-based testing
• Testcase Superclass pattern (uses Template Method pattern)
• Test coverage

Setting up the Environment

Check out the project using Android Studio. This creates the local.properties file with the required line

sdk.dir=<root folder of Android Studio's Android SDK installation>

Running the Application

In Android Studio: Run > Run app

Running the Tests

Unit tests including out-of-emulator system tests using Robolectric

In Android Studio:

• View > Tool Windows > Build Variants
• Test Artifact: Unit Tests
• right-click on app/java/edu.luc.etl.cs313... (test), then choose Run Tests in edu.luc.etl.cs313...

You can also use Gradle:

$ ./gradlew testDebug

You can view the resulting test reports in HTML by opening this file in your browser:

app/build/reports/tests/debug/index.html

Android instrumentation tests (in-emulator/device system tests)

In Android Studio:

• View > Tool Windows > Build Variants
• Test Artifact: Android Instrumentation Tests
• right-click on app/java/edu...simplestopwatch (androidTest), then choose Run Tests in edu...

You can also use Gradle:

$ ./gradlew connectedDebugAndroidTest