AppRootUi

Marks a @Composable function as the application's root host composable, so the codegen processor can emit a provider interface and an extension that the activity's dependency graph implements.

Without this annotation the activity has to invoke the root composable with one argument for each shared dependency the composable accepts. With this annotation the processor reads the composable's parameter list, emits an AppRootProvider interface declaring one val for each non-modifier parameter, and emits a @Composable AppRootProvider.AppRootContent(modifier) extension that invokes the annotated composable using the receiver's properties. The activity call site collapses from one argument per dependency to one extension call.

Example

@Composable
@AppRootUi(presenter = RootPresenter::class, parentScope = ActivityScope::class)
fun RootScreen(
    rootPresenter: RootPresenter,
    screenContents: Set<ScreenContent>,
    sheetContents: Set<SheetContent>,
    modifier: Modifier = Modifier,
) {
    // ... compose UI here
}

The processor emits one file (<FunctionName>AppRootUiBinding.kt) into the same module's <package>.di sub package. The file contains the AppRootProvider interface and the AppRootContent extension. The consumer makes its activity-scope @DependencyGraph extend AppRootProvider, then calls graph.AppRootContent() from the activity.

Composable signature requirement

The annotated function must:

• Be @Composable.

• Declare at least one non-modifier parameter.

• Declare its first non-modifier parameter as the presenter type.

The processor reads the parameter list in order and skips any parameter named modifier whose type is androidx.compose.ui.Modifier. Every other parameter becomes a property on the generated AppRootProvider interface.

Validation

The processor reports a compile error if any of the following hold:

• The annotated symbol is not a function.

• The function lives in the default (empty) package.

• The function has no non-modifier parameters.

• The first non-modifier parameter type does not equal presenter.

• More than one @AppRootUi is declared in the same compilation round.