Memory Image Caching Compose Multiplatform Application

This project is a simple image caching application that loads images from the network and caches them in memory.

Supported platforms: Android, iOS.

Please make sure, before running the project:

• JDK 17 or higher on your machine
• Android Studio Iguana 2023.2.1 or higher
• Kotlin Multiplatform Mobile plugin installed in Android Studio
• local.properties file set a path to Android SDK
• To run the application on iOS, you need to have Xcode installed on your machine.

About the Source Code Detail

• I created a separate imageCaching module for image caching logic to make it reusable for other projects.
• The project is built with Kotlin Multiplatform Mobile (KMM) and uses Jetpack Compose for UI.
• The project is divided into 4 modules:
  • imageCaching - This is Image Caching shared module library that contains the core logic of the image caching
    • imageCaching/commonMain - Shared code for Android and iOS,
    • imageCaching/androidMain - Android Image Decoder,
    • imageCaching/iosMain - iOS Image Decoder .
  • composeApp/commonMain - Shared app code for Android and iOS,
  • composeApp/androidApp - Android specific code,
  • iosApp - iOS specific code.

Code Architecture

• CLEAN & MVVM architecture pattern.
• SOLID Principles.
• The project uses Kotlin Coroutines for asynchronous programming.
• Repository pattern is used to abstract the data layer.

Used Techs

• Kotlin Multiplatform Mobile
• Jetpack Compose
• Ktor
• Koin
• StateFlow
• Kotlin Coroutines
• Kotlin Serialization
• StateHoisting
• Expect and Actual

Handled Use Case

• The application loads images from the network and caches them in memory.
• The application displays a grid of images.
• Network error handling and retry mechanism.
• Image loading indicator.
• Image placeholder.

Compose Unit Tests

• The project contains compose unit tests for the composeApp module.
• Android - To Run simulator UI tests: ./gradlew :composeApp:pixel5Check
• iOS - To Run simulator UI tests: ./gradlew :composeApp:iosSimulatorArm64Test

Android

• To build, run ./gradlew :composeApp:assembleDebug
• find .apk file in composeApp/build/outputs/apk/debug/composeApp-debug.apk
• Android simulator UI tests, run ./gradlew :composeApp:pixel5Check
• Android Screenshot
  • Loading
  • Try Again
  • Gallery

iOS

• To run, iosApp/iosApp.xcproject in Xcode and run standard configuration
• iOS simulator UI tests: ./gradlew :composeApp:iosSimulatorArm64Test
• iOS Screenshot
  • Try Again
  • Gallery

Limitations

• Unsplash loads maximum 30 images on each request, so the gallery will show only 30 images.
• As of now the application does not have a pagination feature.
• API Key is hardcoded in the project, it should be stored in a secure place. If I would have not kept in the project, you would not be able to run the project directly.