Android

The Android host draws the render stream with Jetpack Compose and Material 3 and calls the core over JNI (crates/niso-android, built as libniso_android.so). It comes in two parts:

• hosts/android/niso, an Android library: the engine (Engine.kt), the renderer (NodeView.kt, RenderNode.kt), native controls (Controls.kt), the theme the page sees (Theme.kt) and media (MediaHost.kt). Apps build on it.
• hosts/android/app, the host app: an activity running one page, plus its home screen widget and notifications.

Build and run

hosts/android/build.sh                 # examples/counter on a running emulator or device
hosts/android/build.sh timer           # another example
hosts/android/build.sh --app LIB       # a native app library (arm64, exports niso_app_main)
hosts/android/build.sh --jvm DIR CLASS # a Java or Kotlin app on the dev.niso.dom binding

With no device attached, the script starts the AVD named in NISO_AVD. NISO_APK_LABEL builds a standalone APK instead (hosts/android/apk.sh), and NISO_ENGINE=porffor compiles the page’s script ahead of time with Porffor (Engines). Setup is in Android apps.

What a page gets

The host runs the page’s event loop on every display frame while it animates (niso_dom_needs_frame), and otherwise only when the user acts, a timer is due, or a worker or native module sends something, so an idle page costs nothing. Pages can import native modules written in Kotlin as niso:<name> (Native modules).

• Home screen widget: a Glance widget draws the page’s widget.small or widget.medium template, whichever fits (SurfaceWidget.kt).
• Ongoing notification: while the page has an activity surface, it’s an ongoing notification (Android 16 promotes it to a Live Update). The template maps onto the notification’s fixed slots: first text as the title, a timer as its chronometer, a progress bar, buttons as actions (Surfaces.kt).
• Media: the page’s media session keeps playing in the background with the system’s media notification (MediaHost.kt).

Wear OS, Android TV and Android Auto are planned, not built (Planned platforms).