Rewrite sample app in Kotlin + Jetpack Compose with Clean Architecture by DmBard · Pull Request #273 · sumup/sumup-android-sdk

DmBard · 2026-04-20T21:42:33Z

Replaces the legacy Java/XML sample app (MainActivity.java, SampleApplication.java, activity_main.xml, PNG launcher icons, w820dp resources) with a modern Kotlin and Jetpack Compose implementation that demonstrates the SumUp Reader SDK using a layered, testable architecture.

Architecture

Introduces a Clean Architecture structure with domain/, data/ and presentation/ layers, each holding only framework-appropriate types.
Domain: ReaderSdkRepository interface, pure Kotlin models (MerchantInfo, ConnectedReader, ReaderType, OfflineSession, OfflineSdkError, SdkResult, CheckoutConfiguration) and four suspend-enabled use cases (CreateLoginRequestUseCase, CreateCheckoutRequestUseCase, ParseSdkStatusUseCase, ParsePaymentResultUseCase), all returning Result<T> via runCatching.
Data: ReaderSdkRepositoryImpl wraps the SumUp SDK callbacks as coroutines and delegates conversion to dedicated mappers (MerchantInfoMapper, ConnectedReaderMapper, OfflineSessionMapper).
Presentation: a single MainViewModel exposing StateFlow<UiState> + Channel<UiEvent> drives three Compose screens — WelcomeScreen, CheckoutScreen, SettingsScreen — composed from AmountDisplay, Keypad and CheckoutResultDialog. SdkActionRequest lives in the presentation layer so SumUp SDK types never leak into domain.
Navigation uses NavHost with type-safe routes (Welcome, Checkout, Settings) hosted inside a Scaffold whose padding is propagated down.
Koin wires the whole graph in di/KoinModules.kt; a coroutine dispatcher abstraction (CoroutinesDispatcherProvider + DefaultCoroutinesDispatcherProvider) keeps the ViewModel testable.

UI / UX

Edge-to-edge rendering via enableEdgeToEdge(); screens apply statusBarsPadding() and navigationBarsPadding() and manage system bar icon tint with a SystemBarsAppearance helper.
New design system in theme/ (SparkBlue, Violet, LightSand, …) and typography scale (AmountTextStyle, ButtonLabelStyle, …) plugged into MaterialTheme's Typography slot for consistent Material3 defaults.
Checkout screen features an auto-sizing amount display, custom keypad, reader-status badge, offline indicator and a Material3 Button whose enabled state is bound to isLoggedIn && amountInCents > 0.
Settings screen surfaces tipping configuration (on-reader vs manual), offline-session controls (start/stop, upload transactions, security patch update), developer toggles (result dialog, success screen + custom timeout) and account/logout actions, with preview fixtures for each state.
New launcher icon (adaptive ic_launcher + foreground/background vectors), ic_settings_gear, ic_close, ic_location_pin, ic_sumup_logo, and a bg_welcome_map welcome background.

Error handling & observability

SafeResult.safely/safelySuspend wrap SDK calls, log failures with a consistent tag, and surface user-facing messages via UiState.latestMessage and a Snackbar.
handleFailure extension centralises failure logging and message surfacing while respecting coroutine cancellation.

Build

Adds Compose, Navigation, Koin, Material Icons and lifecycle-viewmodel dependencies; enables Compose compiler and removes obsolete dimens/layouts from build.gradle and resources.

Replaces the legacy Java/XML sample app (MainActivity.java, SampleApplication.java, activity_main.xml, PNG launcher icons, w820dp resources) with a modern Kotlin and Jetpack Compose implementation that demonstrates the SumUp Reader SDK using a layered, testable architecture. Architecture - Introduces a Clean Architecture structure with domain/, data/ and `presentation/` layers, each holding only framework-appropriate types. - Domain: `ReaderSdkRepository` interface, pure Kotlin models (`MerchantInfo`, `ConnectedReader`, `ReaderType`, `OfflineSession`, `OfflineSdkError`, `SdkResult`, `CheckoutConfiguration`) and four `suspend`-enabled use cases (`CreateLoginRequestUseCase`, `CreateCheckoutRequestUseCase`, `ParseSdkStatusUseCase`, `ParsePaymentResultUseCase`), all returning `Result<T>` via `runCatching`. - Data: `ReaderSdkRepositoryImpl` wraps the SumUp SDK callbacks as coroutines and delegates conversion to dedicated mappers (`MerchantInfoMapper`, `ConnectedReaderMapper`, `OfflineSessionMapper`). - Presentation: a single `MainViewModel` exposing `StateFlow<UiState>` + `Channel<UiEvent>` drives three Compose screens — `WelcomeScreen`, `CheckoutScreen`, `SettingsScreen` — composed from `AmountDisplay`, `Keypad` and `CheckoutResultDialog`. `SdkActionRequest` lives in the presentation layer so SumUp SDK types never leak into domain. - Navigation uses `NavHost` with type-safe routes (`Welcome`, `Checkout`, `Settings`) hosted inside a `Scaffold` whose padding is propagated down. - Koin wires the whole graph in `di/KoinModules.kt`; a coroutine dispatcher abstraction (`CoroutinesDispatcherProvider` + `DefaultCoroutinesDispatcherProvider`) keeps the ViewModel testable. UI / UX - Edge-to-edge rendering via `enableEdgeToEdge()`; screens apply `statusBarsPadding()` and `navigationBarsPadding()` and manage system bar icon tint with a `SystemBarsAppearance` helper. - New design system in `theme/` (`SparkBlue`, `Violet`, `LightSand`, …) and typography scale (`AmountTextStyle`, `ButtonLabelStyle`, …) plugged into `MaterialTheme`'s `Typography` slot for consistent Material3 defaults. - Checkout screen features an auto-sizing amount display, custom keypad, reader-status badge, offline indicator and a Material3 `Button` whose `enabled` state is bound to `isLoggedIn && amountInCents > 0`. - Settings screen surfaces tipping configuration (on-reader vs manual), offline-session controls (start/stop, upload transactions, security patch update), developer toggles (result dialog, success screen + custom timeout) and account/logout actions, with preview fixtures for each state. - New launcher icon (adaptive `ic_launcher` + foreground/background vectors), `ic_settings_gear`, `ic_close`, `ic_location_pin`, `ic_sumup_logo`, and a `bg_welcome_map` welcome background. Error handling & observability - `SafeResult.safely`/`safelySuspend` wrap SDK calls, log failures with a consistent tag, and surface user-facing messages via `UiState.latestMessage` and a Snackbar. - `handleFailure` extension centralises failure logging and message surfacing while respecting coroutine cancellation. Build - Adds Compose, Navigation, Koin, Material Icons and lifecycle-viewmodel dependencies; enables Compose compiler and removes obsolete dimens/layouts from `build.gradle` and resources.

Copilot

Pull request overview

Rewrites the sample app from legacy Java/XML to a Kotlin + Jetpack Compose implementation that demonstrates the SumUp Reader SDK using a Clean Architecture split (domain/data/presentation) and Koin wiring.

Changes:

Migrates UI to Compose with navigation, theming, and three primary screens (Welcome/Checkout/Settings).
Introduces domain models + use-cases, plus a repository implementation that wraps SumUp SDK callbacks into coroutines with mappers.
Updates build + resources (Compose/Koin deps, adaptive launcher icons, new strings, removes legacy layouts/dimens).

Reviewed changes

Copilot reviewed 53 out of 60 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
build.gradle	Updates build tooling dependencies (AGP/Kotlin plugin).
app/build.gradle	Enables Kotlin/Compose and adds Compose, Navigation, Koin, lifecycle, coroutines deps.
app/src/main/AndroidManifest.xml	Updates application/activity wiring for new Kotlin application + Compose activity and launcher icons.
app/src/main/java/com/sumup/app/SampleApplication.kt	New Application that initializes SumUpState and starts Koin.
app/src/main/java/com/sumup/sdksampleapp/SampleApplication.java	Removes legacy Java Application class.
app/src/main/java/com/sumup/sdksampleapp/MainActivity.java	Removes legacy Java/XML Activity implementation.
app/src/main/res/layout/activity_main.xml	Removes legacy XML layout.
app/src/main/res/values/strings.xml	Adds Compose UI strings for screens/settings/dialogs.
app/src/main/res/values/dimens.xml	Removes legacy dimens resource.
app/src/main/res/values-w820dp/dimens.xml	Removes tablet-specific legacy dimens override.
app/src/main/res/values/colors.xml	Adds launcher background color resource.
app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml	Adds adaptive launcher icon definition.
app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml	Adds adaptive round launcher icon definition.
app/src/main/res/drawable/ic_launcher_background.xml	Adds new launcher icon background drawable.
app/src/main/res/drawable/ic_launcher_foreground.xml	Adds new launcher icon foreground vector.
app/src/main/res/drawable/ic_sumup_logo.xml	Adds SumUp logo vector used on welcome screen.
app/src/main/res/drawable/ic_settings_gear.xml	Adds settings icon for checkout top bar.
app/src/main/res/drawable/ic_location_pin.xml	Adds location pin vector used on welcome screen.
app/src/main/res/drawable/ic_close.xml	Adds close icon vector (resource set).
app/src/main/res/drawable-nodpi/bg_welcome_map.webp	Adds welcome screen background image asset.
app/src/main/java/com/sumup/app/di/KoinModules.kt	Defines DI graph: dispatchers, mappers, repository, use cases, ViewModel.
app/src/main/java/com/sumup/app/util/CoroutinesDispatcherProvider.kt	Adds dispatcher abstraction for testability.
app/src/main/java/com/sumup/app/util/SafeResult.kt	Adds safe Result wrappers for logging + cancellation-aware error handling.
app/src/main/java/com/sumup/app/util/ResultExt.kt	Adds Result failure handling helper to surface messages.
app/src/main/java/com/sumup/app/data/repository/ReaderSdkRepositoryImpl.kt	Implements SDK repository, wrapping callbacks into suspend functions and mapping SDK models.
app/src/main/java/com/sumup/app/data/mapper/MerchantInfoMapper.kt	Maps SDK merchant to domain MerchantInfo.
app/src/main/java/com/sumup/app/data/mapper/ConnectedReaderMapper.kt	Maps SDK reader details to domain ConnectedReader/ReaderType.
app/src/main/java/com/sumup/app/data/mapper/OfflineSessionMapper.kt	Maps SDK offline session state to domain OfflineSession.
app/src/main/java/com/sumup/app/domain/repository/ReaderSdkRepository.kt	Introduces domain repository interface for SDK operations.
app/src/main/java/com/sumup/app/domain/model/MerchantInfo.kt	Adds pure domain model for merchant info.
app/src/main/java/com/sumup/app/domain/model/ConnectedReader.kt	Adds pure domain model for connected reader info.
app/src/main/java/com/sumup/app/domain/model/ReaderType.kt	Adds domain enum for reader type display mapping.
app/src/main/java/com/sumup/app/domain/model/CheckoutConfiguration.kt	Adds domain config model for checkout behavior and tipping.
app/src/main/java/com/sumup/app/domain/model/OfflineSession.kt	Adds domain model for offline session state + UI cap constant.
app/src/main/java/com/sumup/app/domain/model/OfflineSdkError.kt	Adds typed exceptions for offline operation failures.
app/src/main/java/com/sumup/app/domain/model/SdkResult.kt	Adds unified domain representation of SDK activity results.
app/src/main/java/com/sumup/app/domain/usecase/CreateLoginRequestUseCase.kt	Creates SumUpLogin request as a use case.
app/src/main/java/com/sumup/app/domain/usecase/CreateCheckoutRequestUseCase.kt	Builds SumUpPayment request from UI state + config.
app/src/main/java/com/sumup/app/domain/usecase/ParseSdkStatusUseCase.kt	Parses login/card-reader-page status bundles into SdkResult.Status.
app/src/main/java/com/sumup/app/domain/usecase/ParsePaymentResultUseCase.kt	Parses checkout result bundles into SdkResult.Payment.
app/src/main/java/com/sumup/app/presentation/model/UiState.kt	Adds single StateFlow-backed UI state for app screens.
app/src/main/java/com/sumup/app/presentation/model/UiEvent.kt	Adds UI events for navigation and executing SDK actions.
app/src/main/java/com/sumup/app/presentation/model/SdkActionRequest.kt	Defines presentation-level requests for SDK operations (login/checkout/card reader page).
app/src/main/java/com/sumup/app/presentation/navigation/Route.kt	Defines type-safe route constants for Compose navigation.
app/src/main/java/com/sumup/app/presentation/MainViewModel.kt	Implements app ViewModel: state, events, SDK result parsing, offline operations, settings.
app/src/main/java/com/sumup/app/presentation/MainActivity.kt	Hosts Compose UI, collects events, drives navigation and SDK action dispatch.
app/src/main/java/com/sumup/app/presentation/theme/Theme.kt	Adds Material3 color scheme + typography mapping into MaterialTheme.
app/src/main/java/com/sumup/app/presentation/theme/Type.kt	Defines custom text styles used across screens/components.
app/src/main/java/com/sumup/app/presentation/theme/SystemBars.kt	Adds helper to control system bar icon appearance.
app/src/main/java/com/sumup/app/presentation/screen/WelcomeScreen.kt	Implements welcome screen UI.
app/src/main/java/com/sumup/app/presentation/screen/CheckoutScreen.kt	Implements checkout screen UI (amount, keypad, status badges, result dialog).
app/src/main/java/com/sumup/app/presentation/screen/SettingsScreen.kt	Implements settings UI (tipping/offline/dev options/account).
app/src/main/java/com/sumup/app/presentation/screen/components/AmountDisplay.kt	Adds autosizing amount display component.
app/src/main/java/com/sumup/app/presentation/screen/components/Keypad.kt	Adds custom keypad component.
app/src/main/java/com/sumup/app/presentation/screen/components/CheckoutResultDialog.kt	Adds debug/result dialog component for SDK outcomes.

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…edReaderFlow for polling reader status

HeyPouya · 2026-04-24T10:12:10Z

    }
    dependencies {
-        classpath 'com.android.tools.build:gradle:8.8.2'
+        classpath 'com.android.tools.build:gradle:8.9.1'


Can we use kotlin for all gradle files?

HeyPouya · 2026-04-24T10:13:18Z


 android {
-    namespace "com.sumup.sdksampleapp"
+    namespace "com.sumup.app"


just to make sure it does not clash with any Sumup package names, maybe: com.sumup.sample.app

HeyPouya · 2026-04-24T10:14:00Z


 dependencies {
-    implementation 'com.google.android.gms:play-services-location:21.3.0'
+    implementation platform('androidx.compose:compose-bom:2024.10.01')


Can we use latest dependencies for the sample app?

HeyPouya · 2026-04-24T10:17:52Z

        debug {
            // All ProGuard rules required by the SumUp SDK are packaged with the library
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt')


Can we replace with proguard-android-optimize.txt?

HeyPouya · 2026-04-24T10:19:50Z

    dependencies {
-        classpath 'com.android.tools.build:gradle:8.8.2'
+        classpath 'com.android.tools.build:gradle:8.9.1'
+        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.25'


Can we also use the latest version for gradle and kotlin plugins?

HeyPouya · 2026-04-24T14:39:16Z

+                .getOrDefault(false)
+            if (loggedIn) {
+                refreshMerchantStateInternal()
+                _events.trySend(UiEvent.NavigateToCheckout)


We can change all trySends to send(), as trySend might fail silently.

HeyPouya · 2026-04-24T14:41:08Z

+import org.koin.androidx.viewmodel.dsl.viewModel
+import org.koin.dsl.module
+
+internal val appModule = module {


Since there is only one module for the whole app, we can rename the file to KoinModule.

HeyPouya · 2026-04-24T14:41:53Z

+internal val appModule = module {
+    single<CoroutinesDispatcherProvider> { DefaultCoroutinesDispatcherProvider() }
+
+    single { OfflineSessionMapper() }


Nit: As these are stateless mappers, we can change to factory

HeyPouya · 2026-04-24T14:43:46Z

+import java.math.BigDecimal
+import java.util.UUID
+
+internal class CreateCheckoutRequestUseCase(


Random place: Should we also cover the main logics with tests?

HeyPouya · 2026-04-24T14:48:41Z

+    onBackspace: () -> Unit,
+    onDoubleZeroPressed: () -> Unit,
+) {
+    val rows = listOf(


The list is rebuilt with each recomposition. Maybe hoisting it?

DmBard requested review from HeyPouya and Copilot April 20, 2026 21:42

Copilot started reviewing on behalf of DmBard April 20, 2026 21:43 View session

Copilot AI reviewed Apr 20, 2026

View reviewed changes

DmBard added 2 commits April 21, 2026 11:53

Addresses comments

9cecd59

Refactor ReaderSdkRepository to use suspend functions and add connect…

cf637e1

…edReaderFlow for polling reader status

HeyPouya approved these changes Apr 24, 2026

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DmBard commented Apr 20, 2026

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