Introduces ScreenViewFactoryFinder

workflow-ui/core-android/api/core-android.api

@@ -95,6 +95,20 @@ public final class com/squareup/workflow1/ui/ScreenViewFactory$DefaultImpls {
 	public static synthetic fun buildView$default (Lcom/squareup/workflow1/ui/ScreenViewFactory;Lcom/squareup/workflow1/ui/Screen;Lcom/squareup/workflow1/ui/ViewEnvironment;Landroid/content/Context;Landroid/view/ViewGroup;ILjava/lang/Object;)Landroid/view/View;
 }
 
+public abstract interface class com/squareup/workflow1/ui/ScreenViewFactoryFinder {
+	public static final field Companion Lcom/squareup/workflow1/ui/ScreenViewFactoryFinder$Companion;
+	public abstract fun getViewFactoryForRendering (Lcom/squareup/workflow1/ui/ViewEnvironment;Lcom/squareup/workflow1/ui/Screen;)Lcom/squareup/workflow1/ui/ScreenViewFactory;
+}
+
+public final class com/squareup/workflow1/ui/ScreenViewFactoryFinder$Companion : com/squareup/workflow1/ui/ViewEnvironmentKey {
+	public fun getDefault ()Lcom/squareup/workflow1/ui/ScreenViewFactoryFinder;
+	public synthetic fun getDefault ()Ljava/lang/Object;
+}
+
+public final class com/squareup/workflow1/ui/ScreenViewFactoryFinder$DefaultImpls {
+	public static fun getViewFactoryForRendering (Lcom/squareup/workflow1/ui/ScreenViewFactoryFinder;Lcom/squareup/workflow1/ui/ViewEnvironment;Lcom/squareup/workflow1/ui/Screen;)Lcom/squareup/workflow1/ui/ScreenViewFactory;
+}
+
 public final class com/squareup/workflow1/ui/ScreenViewFactoryKt {
 	public static final fun buildView (Lcom/squareup/workflow1/ui/Screen;Lcom/squareup/workflow1/ui/ViewEnvironment;Landroid/content/Context;Landroid/view/ViewGroup;Lcom/squareup/workflow1/ui/ViewStarter;)Landroid/view/View;
 	public static synthetic fun buildView$default (Lcom/squareup/workflow1/ui/Screen;Lcom/squareup/workflow1/ui/ViewEnvironment;Landroid/content/Context;Landroid/view/ViewGroup;Lcom/squareup/workflow1/ui/ViewStarter;ILjava/lang/Object;)Landroid/view/View;

workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/AndroidViewRegistry.kt

@@ -8,7 +8,7 @@ import android.view.ViewGroup
 import com.squareup.workflow1.ui.container.BackStackScreen
 import kotlin.reflect.KClass
 
-@Deprecated("Use ViewEnvironment.getViewFactoryForRendering()")
+@Deprecated("Use ScreenViewFactoryFinder.getViewFactoryForRendering()")
 @WorkflowUiExperimentalApi
 public fun <RenderingT : Any>
   ViewRegistry.getFactoryForRendering(rendering: RenderingT): ViewFactory<RenderingT> {

workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactory.kt

@@ -3,12 +3,6 @@ package com.squareup.workflow1.ui
 import android.content.Context
 import android.view.View
 import android.view.ViewGroup
-import com.squareup.workflow1.ui.container.BackStackScreen
-import com.squareup.workflow1.ui.container.BackStackScreenViewFactory
-import com.squareup.workflow1.ui.container.BodyAndModalsContainer
-import com.squareup.workflow1.ui.container.BodyAndModalsScreen
-import com.squareup.workflow1.ui.container.EnvironmentScreen
-import com.squareup.workflow1.ui.container.EnvironmentScreenViewFactory
 
 /**
  * Factory for [View] instances that can show renderings of type [RenderingT] : [Screen].
@@ -63,7 +57,9 @@ public fun <ScreenT : Screen> ScreenT.buildView(
   container: ViewGroup? = null,
   viewStarter: ViewStarter? = null,
 ): View {
-  val viewFactory = viewEnvironment.getViewFactoryForRendering(this)
+  val viewFactory = viewEnvironment[ScreenViewFactoryFinder].getViewFactoryForRendering(
+    viewEnvironment, this
+  )
 
   return viewFactory.buildView(this, viewEnvironment, contextForNewView, container).also { view ->
     checkNotNull(view.workflowViewStateOrNull) {
@@ -97,28 +93,3 @@ public fun interface ViewStarter {
     doStart: () -> Unit
   )
 }
-
-@WorkflowUiExperimentalApi
-internal fun <ScreenT : Screen>
-  ViewEnvironment.getViewFactoryForRendering(rendering: ScreenT): ScreenViewFactory<ScreenT> {
-  val entry = get(ViewRegistry).getEntryFor(rendering::class)
-
-  @Suppress("UNCHECKED_CAST", "DEPRECATION")
-  return (entry as? ScreenViewFactory<ScreenT>)
-    ?: (rendering as? AndroidScreen<*>)?.viewFactory as? ScreenViewFactory<ScreenT>
-    ?: (rendering as? AsScreen<*>)?.let { AsScreenViewFactory as ScreenViewFactory<ScreenT> }
-    ?: (rendering as? BackStackScreen<*>)?.let {
-      BackStackScreenViewFactory as ScreenViewFactory<ScreenT>
-    }
-    ?: (rendering as? BodyAndModalsScreen<*, *>)?.let {
-      BodyAndModalsContainer as ScreenViewFactory<ScreenT>
-    }
-    ?: (rendering as? NamedScreen<*>)?.let { NamedScreenViewFactory as ScreenViewFactory<ScreenT> }
-    ?: (rendering as? EnvironmentScreen<*>)?.let {
-      EnvironmentScreenViewFactory as ScreenViewFactory<ScreenT>
-    }
-    ?: throw IllegalArgumentException(
-      "A ScreenViewFactory should have been registered to display $rendering, " +
-        "or that class should implement AndroidScreen. Instead found $entry."
-    )
-}

workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/ScreenViewFactoryFinder.kt

@@ -0,0 +1,85 @@
+package com.squareup.workflow1.ui
+
+import com.squareup.workflow1.ui.container.BackStackScreen
+import com.squareup.workflow1.ui.container.BackStackScreenViewFactory
+import com.squareup.workflow1.ui.container.BodyAndModalsContainer
+import com.squareup.workflow1.ui.container.BodyAndModalsScreen
+import com.squareup.workflow1.ui.container.EnvironmentScreen
+import com.squareup.workflow1.ui.container.EnvironmentScreenViewFactory
+
+/**
+ * [ViewEnvironment] service object used by [Screen.buildView] to find the right
+ * [ScreenViewFactory]. The default implementation makes [AndroidScreen] work
+ * and provides default bindings for [NamedScreen], [EnvironmentScreen], [BackStackScreen],
+ * etc.
+ *
+ * Here is how this hook could be used to provide a custom view to handle [BackStackScreen]:
+ *
+ *    object MyViewFactory : ScreenViewFactory<BackStackScreen<*>>
+ *    by ManualScreenViewFactory(
+ *      type = BackStackScreen::class,
+ *      viewConstructor = { initialRendering, initialEnv, context, _ ->
+ *        MyBackStackContainer(context)
+ *          .apply {
+ *            layoutParams = (LayoutParams(MATCH_PARENT, MATCH_PARENT))
+ *            bindShowRendering(initialRendering, initialEnv, ::update)
+ *          }
+ *      }
+ *    )
+ *
+ *    object MyFinder : ScreenViewFactoryFinder {
+ *      @Suppress("UNCHECKED_CAST")
+ *      if (rendering is BackStackScreen<*>)
+ *        return MyViewFactory as ScreenViewFactory<ScreenT>
+ *      return super.getViewFactoryForRendering(environment, rendering)
+ *    }
+ *
+ *    class MyViewModel(savedState: SavedStateHandle) : ViewModel() {
+ *      val renderings: StateFlow<MyRootRendering> by lazy {
+ *        val customized = ViewEnvironment() + (ScreenViewFactoryFinder to MyFinder)
+ *        renderWorkflowIn(
+ *          workflow = MyRootWorkflow.withEnvironment(customized),
+ *          scope = viewModelScope,
+ *          savedStateHandle = savedState
+ *        )
+ *      }
+ *    }
+ */
+
+@WorkflowUiExperimentalApi
+public interface ScreenViewFactoryFinder {
+  public fun <ScreenT : Screen> getViewFactoryForRendering(
+    environment: ViewEnvironment,
+    rendering: ScreenT
+  ): ScreenViewFactory<ScreenT> {
+    val entry = environment[ViewRegistry].getEntryFor(rendering::class)
+
+    @Suppress("UNCHECKED_CAST", "DEPRECATION")
+    return (entry as? ScreenViewFactory<ScreenT>)
+      ?: (rendering as? AndroidScreen<*>)?.viewFactory as? ScreenViewFactory<ScreenT>
+      ?: (rendering as? AsScreen<*>)?.let { AsScreenViewFactory as ScreenViewFactory<ScreenT> }
+      ?: (rendering as? BackStackScreen<*>)?.let {
+        BackStackScreenViewFactory as ScreenViewFactory<ScreenT>
+      }
+      ?: (rendering as? BodyAndModalsScreen<*, *>)?.let {
+        BodyAndModalsContainer as ScreenViewFactory<ScreenT>
+      }
+      ?: (rendering as? NamedScreen<*>)?.let {
+        NamedScreenViewFactory as ScreenViewFactory<ScreenT>
+      }
+      ?: (rendering as? EnvironmentScreen<*>)?.let {
+        EnvironmentScreenViewFactory as ScreenViewFactory<ScreenT>
+      }
+      ?: throw IllegalArgumentException(
+        "A ScreenViewFactory should have been registered to display $rendering, " +
+          "or that class should implement AndroidScreen. Instead found $entry."
+      )
+  }
+
+  public companion object : ViewEnvironmentKey<ScreenViewFactoryFinder>(
+    ScreenViewFactoryFinder::class
+  ) {
+    override val default: ScreenViewFactoryFinder
+      get() = object : ScreenViewFactoryFinder {}
+  }
+}

workflow-ui/core-android/src/test/java/com/squareup/workflow1/ui/ScreenViewFactoryTest.kt

@@ -74,7 +74,7 @@ internal class ScreenViewFactoryTest {
 
       return mock {
         on {
-          getTag(eq(com.squareup.workflow1.ui.R.id.workflow_ui_view_state))
+          getTag(eq(R.id.workflow_ui_view_state))
         } doReturn (WorkflowViewState.New(initialRendering, initialViewEnvironment, { _, _ -> }))
       }
     }