Claude Android Ninja

Android Kotlin Compose Development

Context ladder (smaller load first; full references stay complete):

1. This file (SKILL.md) - routing, stop rules, examples.
2. references/*-quick.md when listed below - required/forbidden + section links (~40 lines).
3. One target section in the full references/*.md - code samples and checklists only.
4. [INDEX-sections.md](references/INDEX-sections.md) - anchor dump only when quick routing is insufficient.

Forbidden: load [INDEX-sections.md](references/INDEX-sections.md) or an entire multi-thousand-line reference when one section or a quick file covers the task.

Route tasks through the Quick Reference table. When no row matches, or the task needs greenfield bootstrap: [workflows.md](references/workflows.md). Full file list: [INDEX.md](references/INDEX.md).

Required:

• Existing project: read settings.gradle.kts, gradle/libs.versions.toml, and the app module build file before copying from assets/ - [dependencies.md](references/dependencies.md#existing-project-brownfield), [modularization.md](references/modularization.md#existing-project-alignment). Stack migrations: [migration.md](references/migration.md).
• Greenfield: [workflows.md](references/workflows.md) → "Creating a new project?"
• After module, DI, navigation, Room schema, or AGP/Kotlin/KSP changes: ./gradlew help then :app:assembleDebug (use the real app module name) - [gradle-setup.md](references/gradle-setup.md#verify-after-toolchain-or-module-changes).

Outside-repo stop rules (do not substitute repo edits): Play upload, tracks, rollout, versionCode - [android-ci-cd.md](references/android-ci-cd.md); Play Integrity prerequisites (Console/Cloud setup) - [android-security-quick.md](references/android-security-quick.md); production adb install / pm clear - [testing.md](references/testing.md#agent-automation-adb-and-uiautomator).

Quick Reference

Rare or niche topics not listed here are in [INDEX.md](references/INDEX.md) (complete file list).

| Task | Reference | |----------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Task not in table, greenfield bootstrap, multi-topic setup | [workflows.md](references/workflows.md) | | Full index of all reference files | [INDEX.md](references/INDEX.md) | | Version catalog, pins, alpha policy, brownfield alignment | [dependencies.md](references/dependencies.md#version-strategy) | | Adding or updating dependencies (catalog aliases) | [dependencies.md](references/dependencies.md) | | Multi-module dependencies | [dependencies.md](references/dependencies.md) | | Project structure and modules | [modularization.md](references/modularization.md) | | MVVM layers, repositories, DI | [architecture.md](references/architecture.md) | | Retrofit / OkHttp, NetworkModule, nullable DTOs, AuthInterceptor | [architecture.md](references/architecture.md#network-layer-setup-corenetwork); [dependencies.md](references/dependencies.md) | | DataStore (preferences, typed), Room vs DataStore rules | [architecture.md](references/architecture.md#datastore-preferences-typed) | | Code formatting (Spotless, spotlessCheck / spotlessApply) | [assets/convention/QUICKREFERENCE.md](assets/convention/QUICKREFERENCE.md#spotless-plugin); [gradle-setup.md](references/gradle-setup.md) | | Compose patterns, motion, animation, modifiers, stability | [compose-patterns-quick.md](references/compose-patterns-quick.md) | | Paging 3 + Room + network (RemoteMediator, remote keys, initialize) | [compose-patterns.md](references/compose-patterns.md#offline-first-paging-and-remotemediator) | | Accessibility, TalkBack, label copy, live regions, Espresso a11y | [android-accessibility-quick.md](references/android-accessibility-quick.md) | | Notifications, foreground services, MediaStyle, PiP, sharesheet | [android-notifications.md](references/android-notifications.md) | | Media: API 37 background playback, Media3, picking, FileProvider, sharesheet | [android-media.md](references/android-media.md) | | Data sync and offline-first patterns | [android-data-sync-quick.md](references/android-data-sync-quick.md) | | Material 3 theming, spacing tokens, dynamic colors | [android-theming-quick.md](references/android-theming-quick.md) | | Navigation3, deep links, App Links, adaptive layouts | [android-navigation-quick.md](references/android-navigation-quick.md) | | Kotlin patterns, View lifecycle interop | [kotlin-patterns.md](references/kotlin-patterns.md) | | Coroutine patterns (StateFlow, Channel, callbackFlow) | [coroutines-patterns-quick.md](references/coroutines-patterns-quick.md) | | Gradle, product flavors, BuildConfig, build performance, R8 | [gradle-setup.md](references/gradle-setup.md) | | Code quality (Detekt convention plugin, CI) | [code-quality.md](references/code-quality.md) | | Testing approach (unit, instrumented, Compose UI) | [testing-quick.md](references/testing-quick.md) | | Internationalization and localization | [android-i18n.md](references/android-i18n.md) | | Runtime permissions, Photo Picker, API 37 location privacy | [android-permissions.md](references/android-permissions.md) | | Kotlin delegation patterns | [kotlin-delegation.md](references/kotlin-delegation.md) | | Crash reporting (Firebase / Sentry interfaces, PII scrubbing) | [crashlytics.md](references/crashlytics.md) | | Design patterns (GoF-style, Room FTS) | [design-patterns-quick.md](references/design-patterns-quick.md) | | Performance, Play Vitals, startup, recomposition, jank, APA, Perfetto | [android-performance.md](references/android-performance.md) | | Debugging, Logcat, ANR, Gradle errors, R8 mapping, memory leaks | [android-debugging.md](references/android-debugging.md) | | Migrations (XML, RxJava, Navigation, Compose, Room 2→3, API 37, 16 KB native, Compose-XML interop) | [migration.md](references/migration.md); [16 KB page size](references/migration.md#16-kb-memory-page-size-play-and-native-code); [Compose-XML interop](references/migration.md#compose-xml-interop-hardening) |

Examples

Greenfield Android app with convention plugins

User goal: new repo matching the skill stack.

Actions: copy assets/settings.gradle.kts.template, assets/libs.versions.toml.template, assets/convention/ into build-logic/ per assets/convention/QUICK_REFERENCE.md; wire includeBuild("build-logic"); read [modularization.md](references/modularization.md) and [gradle-setup.md](references/gradle-setup.md).

Result: root + app + core modules with version catalog and convention plugins applied.

New feature screen (Compose + ViewModel)

User goal: one new flow in a feature module.

Actions: [modularization.md](references/modularization.md) for module naming and dependency direction; [compose-patterns-quick.md](references/compose-patterns-quick.md) for Screen, state, effects; [kotlin-patterns.md](references/kotlin-patterns.md) + [coroutines-patterns-quick.md](references/coroutines-patterns-quick.md) for StateFlow / events; [architecture.md](references/architecture.md) for domain vs data boundaries.

Result: feature module with Screen composable, ViewModel, UiState, and DI aligned to existing graphs.

Offline-first list with Room 3 and remote API

User goal: cached list + network refresh.

Actions: [compose-patterns.md](references/compose-patterns.md#offline-first-paging-and-remotemediator) for Paging 3 + RemoteMediator; [architecture.md](references/architecture.md) for repository placement; Room 3 + SQLiteDriver per [workflows.md](references/workflows.md) (Working with databases) and [migration.md](references/migration.md#room-2x-to-room-3) if upgrading.

Result: single source of truth in Room, UI driven by PagingData or equivalent pattern from the guide.

Target SDK / compile SDK bump (e.g. API 37)

User goal: migrate toolchain and platform requirements.

Actions: walk [migration.md](references/migration.md#android-17-api-37-migration); pin AGP/Kotlin/KSP using [gradle-setup.md](references/gradle-setup.md) and [dependencies.md](references/dependencies.md); cross-check edge-to-edge, media, security per [workflows.md](references/workflows.md) (Migrating to target SDK 37).

Result: compileSdk / targetSdk raised with manifest, Gradle, and feature code adjusted per the migration doc.

Troubleshooting

| Symptom | Likely cause | Fix | |----------------------------------------------------------------------|--------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Gradle sync fails, plugin not found, or version catalog errors | Missing google() / mavenCentral(), wrong plugin id, or catalog alias drift | [gradle-setup.md](references/gradle-setup.md); align with assets/libs.versions.toml.template when bootstrapping

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Drjacky
• Source: Drjacky/claude-android-ninja
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.