Basic initialization

Start with NativeUIProjection when a plugin owns a native view and a corresponding
Web container. Registration starts the runtime, binds that container and coordinates
image handoff and restoration. You do not need the renderer APIs for this route.

Use the Capacitor or Cordova guide for
dependency installation, plugin lifecycle hooks and notification forwarding.
The examples below show the smallest registration within those hooks, followed by
required inputs. After initialization, the configuration guide lists optional
behavior; advanced APIs have their own entry point.

For example, a plugin already draws a native tab bar, but an application opens a
Web settings sheet above it. Register the bar and its fallback navigation host so
the Engine can put the captured bar beneath that sheet and restore native input
when it closes. The plugin keeps its existing tab selection API.

Minimal initialization

Create and retain one registration after your renderer has attached its native
view. The selector may match a DOM container added later, but native presentation
waits until that container exists. Give it a supported layout box.

In a Capacitor Swift plugin, inside load() or the existing renderer initializer:

projection = try NativeUIProjection(
    webView: bridge?.webView,
    plugin: jsName,
    projectionSelector: "#native-ui-fallback",
    view: { [weak self] in self?.nativeView }
)

In a Capacitor Kotlin plugin, install the shared channel in load() before the
first WebView navigation. The registration may be created later when its view is ready:

NativeUIProjection.install(bridge.webView)
projection = NativeUIProjection(
    window = activity.window,
    webView = bridge.webView,
    plugin = pluginHandle.id,
    projectionSelector = "#native-ui-fallback",
    view = { nativeView }
)

Both snippets belong inside the integration guide's error boundary; retain the
existing Web fallback if initialization fails. projection and nativeView are
properties of your plugin. Dispose the registration with destroy() on iOS or
close() on Android when that renderer is retired. All native lifecycle calls
run on the UI thread.

Cordova uses the same registration with runtime: .cordova / runtime = Runtime.CORDOVA
and its own WebView and plugin identity. Follow the Cordova guide
for those hooks and Android's resource handler.

Required inputs

These inputs establish ownership. They do not tell the Engine when content
changes or when an application transition should change presentation.

Next: configure changing UI

The minimal registration establishes ownership. Continue with optional settings
for event wiring, value reflection, capture and failure policy. Each setting lists
its default and when it is needed. See advanced APIs only when
your renderer already manages batches, placement or update reconciliation.

Documentation overview