Splash-Android

Splash DSL rendered to native Android widgets from Rust — the Android peer of Splash-OH, which does the same against OpenHarmony's ArkUI.

probe/      the feasibility probe   — splash-render -> android.widget.*, framework widgets only
catalog/    the Material catalog    — 42 screens of Splash DSL -> com.google.android.material.*

Both run on device (OnePlus 6T, Android 11 / SDK 30).

The shape

.splash  ──►  makepad-script VM  ──►  node tree  ──►  flat buffer  ──►  Java builder  ──►  Views
              (via splash-render;        (Rust)      ONE JNI call      (owns every View)
               no makepad renderer)

Java owns every View; Rust owns integer ids and the card state. No jobject is ever held in Rust, so ART's 512-local-reference abort and the FindClass classloader trap are structurally unreachable.

There is no makepad renderer in the process — no makepad-platform, no makepad-draw, no makepad-widgets, no GL surface. The only makepad code linked in is makepad-script, the language VM, whose own dependencies are error_log, math, live_id, script-derive, smallvec, regex, html.

Why Android is not a port of Splash-OH

OpenHarmony ships arkui/native_node.h — a C NDK for widget construction. Android has no equivalent: 62 headers in the NDK's android/ directory, none of them a widget API. Every android.widget.* object must be constructed through JNI into ART, and unlike ArkUI there is no native tier beneath the managed object. So Splash-OH's 2.5–3× construction win does not transfer, and the design goal here is minimising boundary crossings, not avoiding managed-language objects.

See docs/ in octos-one (SPLASH-ANDROID-NATIVE-WIDGETS.md) for the full analysis.

catalog/

A reproduction of material-components-android's catalog: 42 screens, every one authored in the Splash DSL and evaluated on device. Includes real MaterialAlertDialogBuilder / Snackbar / MaterialDatePicker / MaterialTimePicker / BottomSheetDialog / SideSheetDialog / PopupMenu / DrawerLayout, a real Carousel, and live Material motion (MaterialContainerTransform, MaterialSharedAxis, MaterialFadeThrough).

It also carries octos-one's own makepad widgets ported to Android views — WeatherIconView, NavMapView, GlassPanelView — the ones previously written off as having no android.widget equivalent.

See catalog/README.md.

Build

Both need the Android NDK and a JDK. The catalog uses Gradle (which is what makes androidx and Material available at all); the probe builds an APK by hand with aapt2/javac/d8.

# catalog
cd catalog/rust && cargo build --release --target aarch64-linux-android
cp target/aarch64-linux-android/release/libsplash_catalog.so ../app/src/main/jniLibs/arm64-v8a/
cd .. && gradle assembleDebug && adb install -r app/build/outputs/apk/debug/app-debug.apk

# probe
cd probe && ./build.sh

catalog/rust also has a host-side check that needs no device:

cd catalog/rust && cargo run --release --example probe   # evaluates all 42 routes

Status

• ✅ feasibility probe — framework widgets, real IME, full accessibility tree
• ✅ Material catalog — 42 screens, 0 placeholders, 0 exceptions on device
• ✅ octos-one widget ports — WeatherIcon (8 conditions), MapView (3 nav modes), glass panels
• ⏳ the UiNode delta/event contract — construction is done; incremental updates are not
• ⏳ splash-render upstreaming: a Native/Custom node kind, a key attribute for reconciliation, and Serialize derives

Licence

MIT OR Apache-2.0, matching makepad.