Building#

Requirements#

The SDK is located through ANDROID_HOME, ANDROID_SDK_ROOT, the Homebrew android-commandlinetools prefix or ~/Library/Android/sdk, in that order (cmake/AndroidToolchain.cmake). There is no Gradle: the APK is assembled by CMake.

On macOS with Homebrew, put the JDK on the path before building:

export PATH="/opt/homebrew/opt/openjdk@17/bin:$PATH"

Presets#

cmake --preset android-release
cmake --build --preset android-release        # builds and packages the APK
cmake --build build/android-release --target apk-install
cmake --build build/android-release --target apk-run

apk-install runs adb install -r; apk-run also launches the activity. A debug keystore is created next to the build on first use if ~/.android/debug.keystore is missing.

Dependencies#

All third-party code is fetched with FetchContent and pinned in one place, cmake/Dependencies.cmake:

• simdjson: parses InnerTube responses.
• curl + mbedTLS (Android): HTTP transport. mbedTLS is built with its threading layer (cmake/MbedtlsConfig.h) because thumbnails, avatars and metadata are fetched concurrently.
• Dear ImGui: immediate-mode drawing and the text input widget.
• FreeType (Android): glyph rasterisation through imgui_freetype, including the named instances of variable fonts. Built without zlib, bzip2, PNG, HarfBuzz and Brotli.

Sources are collected with file(GLOB_RECURSE ... CONFIGURE_DEPENDS), so new files are picked up by re-running the build; no CMake list needs editing.

Packaging#

cmake/AndroidPackaging.cmake turns the shared library into an APK:

1. aapt2 compile builds the resources and aapt2 link links them with android/AndroidManifest.xml.in (SlopTubeActivity, a NativeActivity, and the playback service and upload job) against android.jar.
2. The Java bridge (android/java/*.java.in, configured with the application id as package) is compiled by javac --release 11 -Werror against android.jar, packed with jar and dexed by d8 into classes.dex.
3. The library is stored uncompressed (zip -0) so it can be mapped directly (extractNativeLibs="false"); classes.dex is added next to it.
4. zipalign -P 16 aligns it for 16 KB page devices.
5. apksigner signs with the debug keystore, or the release key for releases (see releasing.md).

Icon#

android/logo.svg is the only source of the logo. cmake/Logo.cmake reads its paths, stroke and gradient, and fills:

• the templates of android/res/ (an adaptive launcher icon with a monochrome layer for themed icons, and the theme whose background Android's splash screen uses; the colour comes from kBackground in Theme.hpp);
• src/app/ui/LogoShape.hpp.in, the shape drawn by the launch animation.

The SVG must keep its simple layout: one id per path (play, drips), absolute M/L/C/Z commands only, one stroke width and two gradient stops. Configuration fails otherwise.

The version code is derived from the project version: MAJOR * 10000 + MINOR * 100 + PATCH.

Continuous integration#

.github/workflows/ci.yml runs on every push to main, on v* tags and on pull requests:

Fetched dependencies are cached per hash of cmake/Dependencies.cmake.

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