wip: getting nav consistent, pause to improve BackStackScreen types

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/RootWorkflow.kt → samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/RootNavigationWorkflow.kt

@@ -7,14 +7,13 @@ import com.squareup.workflow1.renderChild
 import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.container.BackStackScreen
-import com.squareup.workflow1.ui.container.toBackStackScreen
-import workflow.tutorial.RootWorkflow.State
-import workflow.tutorial.RootWorkflow.State.Todo
-import workflow.tutorial.RootWorkflow.State.Welcome
-import workflow.tutorial.TodoWorkflow.TodoProps
+import workflow.tutorial.RootNavigationWorkflow.State
+import workflow.tutorial.RootNavigationWorkflow.State.Todo
+import workflow.tutorial.RootNavigationWorkflow.State.Welcome
+import workflow.tutorial.TodoNavigationWorkflow.TodoProps
 
 @OptIn(WorkflowUiExperimentalApi::class)
-object RootWorkflow : StatefulWorkflow<Unit, State, Nothing, BackStackScreen<Screen>>() {
+object RootNavigationWorkflow : StatefulWorkflow<Unit, State, Nothing, BackStackScreen<*>>() {
 
   sealed class State {
     object Welcome : State()
@@ -31,37 +30,29 @@ object RootWorkflow : StatefulWorkflow<Unit, State, Nothing, BackStackScreen<Scr
     renderProps: Unit,
     renderState: State,
     context: RenderContext
-  ): BackStackScreen<Screen> {
-
-    // Our list of back stack items. Will always include the "WelcomeScreen".
-    val backstackScreens = mutableListOf<Screen>()
-
+  ): BackStackScreen<*> {
     // Render a child workflow of type WelcomeWorkflow. When renderChild is called, the
     // infrastructure will create a child workflow with state if one is not already running.
     val welcomeScreen = context.renderChild(WelcomeWorkflow) { output ->
       // When WelcomeWorkflow emits LoggedIn, turn it into our login action.
       login(output.username)
     }
-    backstackScreens += welcomeScreen
 
-    when (renderState) {
+    return when (renderState) {
       // When the state is Welcome, defer to the WelcomeWorkflow.
       is Welcome -> {
-        // We always add the welcome screen to the backstack, so this is a no op.
+        BackStackScreen(welcomeScreen)
       }
 
       // When the state is Todo, defer to the TodoListWorkflow.
       is Todo -> {
-        val todoListScreens = context.renderChild(TodoWorkflow, TodoProps(renderState.username)) {
+        val todoBackStack = context.renderChild(TodoNavigationWorkflow, TodoProps(renderState.username)) {
           // When receiving a Back output, treat it as a logout action.
           logout
         }
-        backstackScreens.addAll(todoListScreens)
+        BackStackScreen(welcomeScreen) + todoBackStack
       }
     }
-
-    // Finally, return the BackStackScreen with a list of BackStackScreen.Items
-    return backstackScreens.toBackStackScreen()
   }
 
   override fun snapshotState(state: State): Snapshot? = null

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoEditRunner.kt

@@ -16,8 +16,8 @@ class TodoEditRunner(
     rendering: TodoEditScreen,
     environment: ViewEnvironment
   ) {
-    binding.root.setBackHandler(rendering.onBackClick)
-    binding.save.setOnClickListener { rendering.onSaveClick() }
+    binding.root.setBackHandler(rendering.onBackPressed)
+    binding.save.setOnClickListener { rendering.onSavePressed() }
     rendering.title.control(binding.todoTitle)
     rendering.note.control(binding.todoNote)
   }

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoEditScreen.kt

@@ -13,8 +13,8 @@ data class TodoEditScreen(
   /** The contents, or "note" of the todo. */
   val note: TextController,
 
-  val onBackClick: () -> Unit,
-  val onSaveClick: () -> Unit
+  val onBackPressed: () -> Unit,
+  val onSavePressed: () -> Unit
 ) : AndroidScreen<TodoEditScreen> {
   override val viewFactory =
     ScreenViewFactory.fromViewBinding(TodoEditViewBinding::inflate, ::TodoEditRunner)

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoEditWorkflow.kt

@@ -56,8 +56,8 @@ object TodoEditWorkflow : StatefulWorkflow<EditProps, State, Output, TodoEditScr
     return TodoEditScreen(
         title = renderState.todo.title,
         note = renderState.todo.note,
-        onSaveClick = { context.actionSink.send(postSave) },
-        onBackClick = { context.actionSink.send(postDiscard) }
+        onSavePressed = { context.actionSink.send(postSave) },
+        onBackPressed = { context.actionSink.send(postDiscard) }
     )
   }
 

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoListScreen.kt

@@ -16,8 +16,8 @@ data class TodoListScreen(
   val username: String,
   val todoTitles: List<String>,
   val onTodoSelected: (Int) -> Unit,
-  val onBackClick: () -> Unit,
-  val onAddClick: () -> Unit
+  val onBackPressed: () -> Unit,
+  val onAddPressed: () -> Unit
 ): AndroidScreen<TodoListScreen> {
   override val viewFactory =
     ScreenViewFactory.fromViewBinding(TodoListViewBinding::inflate, ::TodoListScreenRunner)

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoListScreenRunner.kt

@@ -24,8 +24,8 @@ class TodoListScreenRunner(
     rendering: TodoListScreen,
     environment: ViewEnvironment
   ) {
-    todoListBinding.root.setBackHandler(rendering.onBackClick)
-    todoListBinding.add.setOnClickListener { rendering.onAddClick() }
+    todoListBinding.root.setBackHandler(rendering.onBackPressed)
+    todoListBinding.add.setOnClickListener { rendering.onAddPressed() }
 
     with(todoListBinding.todoListWelcome) {
       text =

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoListWorkflow.kt

@@ -32,8 +32,8 @@ object TodoListWorkflow : StatelessWorkflow<ListProps, Output, TodoListScreen>()
       username = renderProps.username,
       todoTitles = titles.map { it.textValue },
       onTodoSelected = { context.actionSink.send(selectTodo(it)) },
-      onBackClick = { context.actionSink.send(postGoBack) },
-      onAddClick = { context.actionSink.send(postNewTodo) }
+      onBackPressed = { context.actionSink.send(postGoBack) },
+      onAddPressed = { context.actionSink.send(postNewTodo) }
     )
   }
 

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoWorkflow.kt → samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TodoNavigationWorkflow.kt

@@ -5,20 +5,21 @@ import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.action
 import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
+import com.squareup.workflow1.ui.container.BackStackScreen
 import workflow.tutorial.TodoEditWorkflow.EditProps
 import workflow.tutorial.TodoEditWorkflow.Output.Discard
 import workflow.tutorial.TodoEditWorkflow.Output.Save
 import workflow.tutorial.TodoListWorkflow.ListProps
 import workflow.tutorial.TodoListWorkflow.Output
 import workflow.tutorial.TodoListWorkflow.Output.NewTodo
 import workflow.tutorial.TodoListWorkflow.Output.SelectTodo
-import workflow.tutorial.TodoWorkflow.Back
-import workflow.tutorial.TodoWorkflow.State
-import workflow.tutorial.TodoWorkflow.State.Step
-import workflow.tutorial.TodoWorkflow.TodoProps
+import workflow.tutorial.TodoNavigationWorkflow.Back
+import workflow.tutorial.TodoNavigationWorkflow.State
+import workflow.tutorial.TodoNavigationWorkflow.State.Step
+import workflow.tutorial.TodoNavigationWorkflow.TodoProps
 
 @OptIn(WorkflowUiExperimentalApi::class)
-object TodoWorkflow : StatefulWorkflow<TodoProps, State, Back, List<Screen>>() {
+object TodoNavigationWorkflow : StatefulWorkflow<TodoProps, State, Back, BackStackScreen<Screen>>() {
 
   data class TodoProps(val name: String)
 
@@ -58,7 +59,7 @@ object TodoWorkflow : StatefulWorkflow<TodoProps, State, Back, List<Screen>>() {
     renderProps: TodoProps,
     renderState: State,
     context: RenderContext
-  ): List<Screen> {
+  ): BackStackScreen<Screen> {
     val todoListScreen = context.renderChild(
       TodoListWorkflow,
       props = ListProps(
@@ -75,7 +76,7 @@ object TodoWorkflow : StatefulWorkflow<TodoProps, State, Back, List<Screen>>() {
 
     return when (val step = renderState.step) {
       // On the "list" step, return just the list screen.
-      Step.List -> listOf(todoListScreen)
+      Step.List -> BackStackScreen(todoListScreen)
       is Step.Edit -> {
         // On the "edit" step, return both the list and edit screens.
         val todoEditScreen = context.renderChild(
@@ -89,7 +90,7 @@ object TodoWorkflow : StatefulWorkflow<TodoProps, State, Back, List<Screen>>() {
             is Save -> saveChanges(output.todo, step.index)
           }
         }
-        return listOf(todoListScreen, todoEditScreen)
+        return BackStackScreen(todoListScreen, todoEditScreen)
       }
     }
   }

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/TutorialActivity.kt

@@ -32,7 +32,7 @@ class TutorialActivity : AppCompatActivity() {
   class TutorialViewModel(savedState: SavedStateHandle) : ViewModel() {
     val renderings: StateFlow<Screen> by lazy {
       renderWorkflowIn(
-        workflow = RootWorkflow,
+        workflow = RootNavigationWorkflow,
         scope = viewModelScope,
         savedStateHandle = savedState
       )

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/WelcomeScreen.kt

@@ -11,7 +11,7 @@ data class WelcomeScreen(
   /** The current name that has been entered. */
   val username: TextController,
   /** Callback when the login button is tapped. */
-  val onLoginTapped: () -> Unit
+  val onLogInPressed: () -> Unit
 ) : AndroidScreen<WelcomeScreen> {
   override val viewFactory =
     ScreenViewFactory.fromViewBinding(WelcomeViewBinding::inflate, ::WelcomeScreenRunner)

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/WelcomeScreenRunner.kt

@@ -18,6 +18,6 @@ class WelcomeScreenRunner(
     // TextController is a helper provided by the workflow library that takes
     // care of the complexity of correctly interacting with EditTexts in a declarative manner.
     rendering.username.control(welcomeBinding.username)
-    welcomeBinding.login.setOnClickListener { rendering.onLoginTapped() }
+    welcomeBinding.login.setOnClickListener { rendering.onLogInPressed() }
   }
 }

samples/tutorial/tutorial-final/src/main/java/workflow/tutorial/WelcomeWorkflow.kt

@@ -28,13 +28,13 @@ object WelcomeWorkflow : StatefulWorkflow<Unit, State, LoggedIn, WelcomeScreen>(
     context: RenderContext
   ): WelcomeScreen = WelcomeScreen(
     username = renderState.name,
-    onLoginTapped = {
-      // Whenever the login button is tapped, emit the onLogin action.
-      context.actionSink.send(onLogin())
+    onLogInPressed = {
+      // Whenever the log in button is tapped, enqueue the logInAction.
+      context.actionSink.send(logInAction())
     }
   )
 
-  internal fun onLogin() = action {
+  internal fun logInAction() = action {
     // Don't log in if the name isn't filled in.
     state.name.textValue.takeIf { it.isNotEmpty() }?.let {
       setOutput(LoggedIn(it))

samples/tutorial/tutorial-final/src/test/java/workflow/tutorial/RootWorkflowTest.kt → samples/tutorial/tutorial-final/src/test/java/workflow/tutorial/RootNavigationWorkflowTest.kt

@@ -7,29 +7,29 @@ import com.squareup.workflow1.testing.testRender
 import com.squareup.workflow1.ui.TextController
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.container.BackStackScreen
-import workflow.tutorial.RootWorkflow.State.Todo
-import workflow.tutorial.RootWorkflow.State.Welcome
+import workflow.tutorial.RootNavigationWorkflow.State.Todo
+import workflow.tutorial.RootNavigationWorkflow.State.Welcome
 import workflow.tutorial.WelcomeWorkflow.LoggedIn
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
 @OptIn(WorkflowUiExperimentalApi::class)
-class RootWorkflowTest {
+class RootNavigationWorkflowTest {
 
   // region Render
 
   @Test fun `welcome rendering`() {
-    RootWorkflow
+    RootNavigationWorkflow
         // Start in the Welcome state
         .testRender(initialState = Welcome, props = Unit)
         // The `WelcomeWorkflow` is expected to be started in this render.
         .expectWorkflow(
             workflowType = WelcomeWorkflow::class,
             rendering = WelcomeScreen(
                 username = TextController("Ada"),
-                onLoginTapped = {}
+                onLogInPressed = {}
             )
         )
         // Now, validate that there is a single item in the BackStackScreen, which is our welcome
@@ -48,15 +48,15 @@ class RootWorkflowTest {
   }
 
   @Test fun `login event`() {
-    RootWorkflow
+    RootNavigationWorkflow
         // Start in the Welcome state
         .testRender(initialState = Welcome, props = Unit)
         // The WelcomeWorkflow is expected to be started in this render.
         .expectWorkflow(
             workflowType = WelcomeWorkflow::class,
             rendering = WelcomeScreen(
                 username = TextController("Ada"),
-                onLoginTapped = {}
+                onLogInPressed = {}
             ),
             // Simulate the WelcomeWorkflow sending an output of LoggedIn as if the "log in" button
             // was tapped.
@@ -82,15 +82,15 @@ class RootWorkflowTest {
   // region Integration
 
   @Test fun `app flow`() {
-    RootWorkflow.launchForTestingFromStartWith {
+    RootNavigationWorkflow.launchForTestingFromStartWith {
       // First rendering is just the welcome screen. Update the name.
       awaitNextRendering().let { rendering ->
         assertEquals(1, rendering.frames.size)
         val welcomeScreen = rendering.frames[0] as WelcomeScreen
 
         // Enter a name and tap login
         welcomeScreen.username.textValue = "Ada"
-        welcomeScreen.onLoginTapped()
+        welcomeScreen.onLogInPressed()
       }
 
       // Expect the todo list to be rendered. Edit the first todo.
@@ -113,7 +113,7 @@ class RootWorkflowTest {
 
         // Enter a title and save.
         editScreen.title.textValue = "New Title"
-        editScreen.onSaveClick()
+        editScreen.onSavePressed()
       }
 
       // Expect the todo list. Validate the title was updated.

samples/tutorial/tutorial-final/src/test/java/workflow/tutorial/TodoWorkflowTest.kt → samples/tutorial/tutorial-final/src/test/java/workflow/tutorial/TodoNavigationWorkflowTest.kt

@@ -7,20 +7,20 @@ import com.squareup.workflow1.ui.TextController
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import workflow.tutorial.TodoEditWorkflow.Output.Save
 import workflow.tutorial.TodoListWorkflow.Output.SelectTodo
-import workflow.tutorial.TodoWorkflow.State
-import workflow.tutorial.TodoWorkflow.State.Step.Edit
-import workflow.tutorial.TodoWorkflow.State.Step.List
-import workflow.tutorial.TodoWorkflow.TodoProps
+import workflow.tutorial.TodoNavigationWorkflow.State
+import workflow.tutorial.TodoNavigationWorkflow.State.Step.Edit
+import workflow.tutorial.TodoNavigationWorkflow.State.Step.List
+import workflow.tutorial.TodoNavigationWorkflow.TodoProps
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 @OptIn(WorkflowUiExperimentalApi::class)
-class TodoWorkflowTest {
+class TodoNavigationWorkflowTest {
 
   @Test fun `selecting todo`() {
     val todos = listOf(TodoModel(title = "Title", note = "Note"))
 
-    TodoWorkflow
+    TodoNavigationWorkflow
       .testRender(
         props = TodoProps(name = "Ada"),
         // Start from the list step to validate selecting a todo.
@@ -36,8 +36,8 @@ class TodoWorkflowTest {
           username = "",
           todoTitles = listOf("Title"),
           onTodoSelected = {},
-          onBackClick = {},
-          onAddClick = {}
+          onBackPressed = {},
+          onAddPressed = {}
         ),
         // Simulate selecting the first todo.
         output = WorkflowOutput(SelectTodo(index = 0))
@@ -62,7 +62,7 @@ class TodoWorkflowTest {
   @Test fun `saving todo`() {
     val todos = listOf(TodoModel(title = "Title", note = "Note"))
 
-    TodoWorkflow
+    TodoNavigationWorkflow
       .testRender(
         props = TodoProps(name = "Ada"),
         // Start from the edit step so we can simulate saving.
@@ -78,8 +78,8 @@ class TodoWorkflowTest {
           username = "",
           todoTitles = listOf("Title"),
           onTodoSelected = {},
-          onBackClick = {},
-          onAddClick = {}
+          onBackPressed = {},
+          onAddPressed = {}
         )
       )
       // Expect the TodoEditWorkflow to be rendered as well (as we're on the edit step).
@@ -88,8 +88,8 @@ class TodoWorkflowTest {
         rendering = TodoEditScreen(
           title = TextController("Title"),
           note = TextController("Note"),
-          onBackClick = {},
-          onSaveClick = {}
+          onBackPressed = {},
+          onSavePressed = {}
         ),
         // Simulate it emitting an output of `.save` to update the state.
         output = WorkflowOutput(