A minimal NativeActivity shim (no Gradle, no Java — android:hasCode="false") that links any native_sdk.addMobileLib static library into a single shared object and shows its canvas scene on an Android device or emulator. Presentation: AChoreographer pumps native_sdk_app_frame (the CADisplayLink twin), and each frame whose canvas revision changed is rendered over the ABI (native_sdk_app_render_pixels, CPU reference renderer, RGBA8) and row-copied into the locked ANativeWindow buffer — WINDOW_FORMAT_RGBA_8888 matches the renderer's byte order, so unlike the iOS Metal path there is no swizzle, only stride-aware copies. Input: AMotionEvent sequences forward through the same touch-slop state machine as the iOS shim (under-slop tap = pointer_down+up, over-slop on an overflowing scrollable widget = wheel deltas through the scroll reconciliation, over-slop elsewhere = pointer drag), with coordinates converted from device pixels to view points by the density scale. Safe-area insets are approximated from onContentRectChanged and reported through native_sdk_app_viewport. Not wired (deliberately, this shim ships zero Java): the soft keyboard / IME path — Android IME needs an InputConnection on the Java side, which is future work — and platform text metrics (layout uses the deterministic estimator; the native_sdk_app_set_text_measure seam is exported and ready).

The C ABI header is shared with the iOS shim (../ios/native_sdk_app.h); run.sh adds it to the include path so the two shims cannot drift.

Run

# mobile-canvas on the attached device / first emulator AVD, arm64-v8a
./run.sh

# ui-inbox through the same shim
./run.sh --example-dir ../../ui-inbox --build-arg -Dmobile=true

# options
./run.sh --abi x86_64        # x86_64 emulator image
./run.sh --lib-only          # stop after the zig static lib + nm symbol check
./run.sh --build-only        # stop after the signed APK

The script cross-compiles the example's embed library (zig build lib -Dtarget=aarch64-linux-android — plain Zig, no NDK sysroot: the static lib links no libc), verifies the shim-required ABI symbols with nm, compiles + links main.c with the NDK's clang into libnative_sdk_shim.so, assembles and signs an APK with aapt2/zipalign/apksigner (no Gradle), installs it with adb, and then verifies three rungs: a non-blank screenshot, an automation snapshot.txt published into the app's files dir (adb shell setprop debug.native_sdk.automation 1 before launch; read back with adb shell run-as), and an injected adb shell input tap on the first button that must change the snapshot.

Requirements past the --lib-only rung: Android SDK (build-tools, platform-tools, a platforms/android-* jar), NDK r23+, and Java for signing. minSdkVersion is 29 — the embed library is built PIC and its thread-locals use TLSDESC relocations, which bionic supports on arm64 from API 29 (also the floor for AChoreographer_postFrameCallback64).

Files

main.c — NativeActivity callbacks + AChoreographer frame pump + ANativeWindow presenter + touch-slop forwarding + automation dir wiring.
AndroidManifest.xml.in — manifest template (__APP_NAME__/__PACKAGE__/__LIB_NAME__ substituted by run.sh).
run.sh — build, link, package, sign, install, launch, screenshot, snapshot, injected tap.