Simple Weather app

• The Android app to display 7 days weather forecast in a ListView.
• Written in Kotlin.
• Follow the Clean Architecture (Data - Domain - Presentation layers) with MVVM.
• Weather data source: OpenWeatherMaps API.
• Allow user to input the searching term (from 3 characters).
• Caching mechanism: offline first (with cache expiry is 10 seconds in Debug mode, and 60 seconds in Release mode), then online later.
• Support orientation change: keep the current search term & forecast result after rotating screen.
• Error handling: Network issue (no network, timeout), Invalid city keyword, Invalid API key or exceed quota, When searching term is less than 3 characters.
• Support the disability to scale large text.
• Support the disability to read out the text using TalkBack controls.

TechStack

Languages

• Kotlin
• Groovy: Gradle (build.gradle)
• YAML: Gradle Version Catalogs (libs.version.toml), Detekt (detekt.yml)

Libraries

• Jetpack: LiveData, ViewModel, Lifecycle, Room, ViewBinding
• Material Design, ConstraintLayout
• Coroutines & Flow
• Dagger Hilt
• Retrofit, OkHttp, Gson.
• hidden-secrets-gradle-plugin to hide the API key in the .so native lib.

Testing, formatting & analysis

• Detekt (static code analysis for Kotlin).
• Spotless (code formatting with Ktlint built-in support).
• Android Lint.
• Unit test: MockK, Robolectric, JUnit, Turbine, MockWebServer, AndroidX test.
• UI (Instrumented test): AndroidX test, Espresso.
• Gradle Version Catalogs as a single source of truth of dependency version. Also use version-catalog-update-plugin to check for out-of-date dependencies.

How to build & run

• Requires tools/SDK: Android Studio Dolphin | 2021.3.1, Android SDK API level 33 & NDK, Java 11.
• To run the Detekt (static code analysis): ./gradlew detekt.
• To view all the Spotless (code formatting) errors/warning: ./gradlew spotlessCheck.
• To apply the Spotless fix automatically: ./gradlew spotlessApply.
• To run Android Lint: ./gradlew app:lintDebug.
• To run unit test: ./gradlew testDebugUnitTest.
• To run instrumented test: ./gradlew connectedAndroidTest.
• To check the out-of-date dependencies: ./gradlew dependencyUpdates -Drevision=release.

Project structure & diagram

Structure

| com.bmtriet.simpleweather

|---- data

|---- ---- local

|---- ---- ----- dao

|---- ---- ----- datasource

|---- ---- ----- entity

|---- ---- mapper

|---- ---- network

|---- ---- ----- datasource

|---- ---- ----- error

|---- ---- ----- interceptor

|---- ---- ----- response

|---- ---- ----- service

|---- ---- repository

|---- di

|---- domain

|---- ---- model

|---- ---- reposity-interface

|---- ---- usecase

|---- presentation

|---- ---- UI model

|---- ---- adapter + viewholder

|---- ---- home (Activity + Fragment + ViewModel)

|---- utils

Diagram

Checklist

• Clean Architecture with MVVM.
• Show the Weather Forecast in the ListView. Error handling as well as caching handling.
• Secure the OpenWeatherMap API key (inside .so). There is no perfect solution to hide API key on the app side.
• Testing: Unit + Instrumented.
• Static code analysis.
• Support accessibility (screen reader) with TalkBack
• Support accessibility with TalkBack

Remaing things to do

Due to time constraint, I cannot finish these thing. It would be the improvement later.

• Setup CI/CI workflow.
• Modularization (at least 4 modules: data, domain, presentation, utils).
• Try the Jetpack Compose as the replacement of XML layout.