WorkflowLayout.start now requires a Lifecycle parameter.

On a lot of Samsung devices running Anroid 12 / API 30, the sketchy `WorkflowLayout.takeWhileAttached` method at the heart of `WorkflowLayout.start` was having surprising effects -- we'd see redundant calls to `View.onAttachedToWindow`. The problem goes away if we get more conventional and use the new `repeatOnLifecycle` function as described in [this blog post](https://medium.com/androiddevelopers/a-safer-way-to-collect-flows-from-android-uis-23080b1f8bda).

The old methods are deprecated and will be deleted soon.

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposebinding/HelloBindingActivity.kt

@@ -35,22 +35,19 @@ class HelloBindingActivity : AppCompatActivity() {
 
     val model: HelloBindingModel by viewModels()
     setContentView(
-        WorkflowLayout(this).apply {
-          start(
-              renderings = model.renderings,
-              environment = viewEnvironment
-          )
-        }
+      WorkflowLayout(this).apply {
+        start(lifecycle, model.renderings, viewEnvironment)
+      }
     )
   }
 
   class HelloBindingModel(savedState: SavedStateHandle) : ViewModel() {
     @OptIn(WorkflowUiExperimentalApi::class)
     val renderings: StateFlow<Any> by lazy {
       renderWorkflowIn(
-          workflow = HelloWorkflow,
-          scope = viewModelScope,
-          savedStateHandle = savedState
+        workflow = HelloWorkflow,
+        scope = viewModelScope,
+        savedStateHandle = savedState
       )
     }
   }

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposeworkflow/HelloComposeWorkflowActivity.kt

@@ -17,7 +17,7 @@ class HelloComposeWorkflowActivity : AppCompatActivity() {
     super.onCreate(savedInstanceState)
     val model: HelloComposeModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings) }
     )
   }
 

samples/compose-samples/src/main/java/com/squareup/sample/compose/inlinerendering/InlineRenderingActivity.kt

@@ -21,9 +21,7 @@ class InlineRenderingActivity : AppCompatActivity() {
 
     val model: HelloBindingModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply {
-        start(renderings = model.renderings)
-      }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings) }
     )
   }
 

samples/compose-samples/src/main/java/com/squareup/sample/compose/nestedrenderings/NestedRenderingsActivity.kt

@@ -38,10 +38,7 @@ class NestedRenderingsActivity : AppCompatActivity() {
     val model: NestedRenderingsModel by viewModels()
     setContentView(
       WorkflowLayout(this).apply {
-        start(
-          renderings = model.renderings,
-          environment = viewEnvironment
-        )
+        start(lifecycle, model.renderings, viewEnvironment)
       }
     )
   }

samples/containers/app-poetry/src/main/java/com/squareup/sample/poetryapp/PoetryActivity.kt

@@ -26,7 +26,7 @@ class PoetryActivity : AppCompatActivity() {
 
     val model: PoetryModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings, viewRegistry) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings, viewRegistry) }
     )
   }
 

samples/containers/app-raven/src/main/java/com/squareup/sample/ravenapp/RavenActivity.kt

@@ -30,7 +30,7 @@ class RavenActivity : AppCompatActivity() {
 
     val model: RavenModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings, viewRegistry) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings, viewRegistry) }
     )
 
     lifecycleScope.launch {

samples/containers/hello-back-button/src/main/java/com/squareup/sample/hellobackbutton/HelloBackButtonActivity.kt

@@ -27,7 +27,7 @@ class HelloBackButtonActivity : AppCompatActivity() {
 
     val model: HelloBackButtonModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings, viewRegistry) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings, viewRegistry) }
     )
 
     lifecycleScope.launch {

samples/dungeon/app/src/main/java/com/squareup/sample/dungeon/DungeonActivity.kt

@@ -17,7 +17,7 @@ class DungeonActivity : AppCompatActivity() {
     val model: TimeMachineModel by viewModels { component.timeMachineModelFactory }
 
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings, component.viewRegistry) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings, component.viewRegistry) }
     )
   }
 }

samples/hello-workflow-fragment/src/main/java/com/squareup/sample/helloworkflowfragment/HelloWorkflowFragment.kt

@@ -23,10 +23,10 @@ class HelloWorkflowFragment : Fragment() {
     // This ViewModel will survive configuration changes. It's instantiated
     // by the first call to ViewModelProvider.get(), and that original instance is returned by
     // succeeding calls, until this Fragment session ends.
-    val model: HelloViewModel = ViewModelProvider(this).get(HelloViewModel::class.java)
+    val model: HelloViewModel = ViewModelProvider(this)[HelloViewModel::class.java]
 
     return WorkflowLayout(inflater.context).apply {
-      start(model.renderings)
+      start(lifecycle, model.renderings)
     }
   }
 }

samples/hello-workflow/src/main/java/com/squareup/sample/helloworkflow/HelloWorkflowActivity.kt

@@ -21,7 +21,7 @@ class HelloWorkflowActivity : AppCompatActivity() {
     // succeeding calls.
     val model: HelloViewModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings) }
     )
   }
 }

samples/stub-visibility/src/main/java/com/squareup/sample/stubvisibility/StubVisibilityActivity.kt

@@ -18,7 +18,7 @@ class StubVisibilityActivity : AppCompatActivity() {
 
     val model: StubVisibilityModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings) }
     )
   }
 }

samples/tictactoe/app/src/main/java/com/squareup/sample/mainactivity/TicTacToeActivity.kt

@@ -31,7 +31,7 @@ class TicTacToeActivity : AppCompatActivity() {
     idlingResource = component.idlingResource
 
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings, viewRegistry) }
+      WorkflowLayout(this).apply { start(lifecycle, model.renderings, viewRegistry) }
     )
 
     lifecycleScope.launch {

samples/todo-android/app/src/main/java/com/squareup/sample/todo/ToDoActivity.kt

@@ -26,7 +26,7 @@ class ToDoActivity : AppCompatActivity() {
 
     setContentView(
       WorkflowLayout(this).apply {
-        start(model.ensureWorkflow(traceFilesDir = filesDir), viewRegistry)
+        start(lifecycle, model.ensureWorkflow(traceFilesDir = filesDir), viewRegistry)
       }
     )
   }

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

@@ -203,8 +203,11 @@ public abstract interface class com/squareup/workflow1/ui/ViewStarter {
 public final class com/squareup/workflow1/ui/WorkflowLayout : android/widget/FrameLayout {
 	public fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
 	public synthetic fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun start (Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;)V
+	public final fun start (Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewRegistry;)V
 	public final fun start (Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;)V
 	public final fun start (Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewRegistry;)V
+	public static synthetic fun start$default (Lcom/squareup/workflow1/ui/WorkflowLayout;Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;ILjava/lang/Object;)V
 	public static synthetic fun start$default (Lcom/squareup/workflow1/ui/WorkflowLayout;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;ILjava/lang/Object;)V
 	public final fun update (Ljava/lang/Object;Lcom/squareup/workflow1/ui/ViewEnvironment;)V
 }

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

@@ -10,12 +10,17 @@ import android.view.View
 import android.view.ViewGroup
 import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.widget.FrameLayout
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.coroutineScope
+import androidx.lifecycle.repeatOnLifecycle
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
 
 /**
  * A view that can be driven by a stream of renderings (and an optional [ViewRegistry])
@@ -47,7 +52,8 @@ public class WorkflowLayout(
    * Calls [WorkflowViewStub.update] on the [WorkflowViewStub] that is the only
    * child of this view.
    *
-   * This is the method called from [start]. It is exposed to allow clients to
+   * It's more common for a `Workflow`-based `Activity` or `Fragment` to use
+   * [start] than to call this method directly. It is exposed to allow clients to
    * make their own choices about how exactly to consume a stream of renderings.
    */
   public fun update(
@@ -61,26 +67,60 @@ public class WorkflowLayout(
     }
   }
 
+  @Deprecated(
+    "Use a variant that takes a Lifecycle argument",
+    ReplaceWith("start(lifecycle, renderings, environment)")
+  )
+  public fun start(
+    renderings: Flow<Any>,
+    environment: ViewEnvironment = ViewEnvironment()
+  ) {
+    @Suppress("DEPRECATION")
+    takeWhileAttached(renderings) { update(it, environment) }
+  }
+
+  @Deprecated(
+    "Use a variant that takes a Lifecycle argument",
+    ReplaceWith("start(lifecycle, renderings, registry)")
+  )
+  public fun start(
+    renderings: Flow<Any>,
+    registry: ViewRegistry
+  ) {
+    @Suppress("DEPRECATION")
+    start(renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
+  }
+
   /**
    * This is the most common way to bootstrap a [Workflow][com.squareup.workflow1.Workflow]
-   * driven UI. Collects [renderings], and calls [start] with each one and [environment].
+   * driven UI. Collects [renderings], and calls [update] with each one and [environment].
+   *
+   * @param [lifecycle] the lifecycle that defines when and how this view should be updated.
+   * Typically this comes from `ComponentActivity.lifecycle` or  `Fragment.lifecycle`.
    */
   public fun start(
+    lifecycle: Lifecycle,
     renderings: Flow<Any>,
     environment: ViewEnvironment = ViewEnvironment()
   ) {
-    takeWhileAttached(renderings) { update(it, environment) }
+    // Just like https://medium.com/androiddevelopers/a-safer-way-to-collect-flows-from-android-uis-23080b1f8bda
+    lifecycle.coroutineScope.launch {
+      lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
+        renderings.collect { update(it, environment) }
+      }
+    }
   }
 
   /**
    * A convenience overload that builds a [ViewEnvironment] around [registry],
    * for a bit less boilerplate.
    */
   public fun start(
+    lifecycle: Lifecycle,
     renderings: Flow<Any>,
     registry: ViewRegistry
   ) {
-    start(renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
+    start(lifecycle, renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
   }
 
   override fun onSaveInstanceState(): Parcelable {
@@ -136,6 +176,7 @@ public class WorkflowLayout(
   /**
    * Subscribes [update] to [source] only while this [View] is attached to a window.
    */
+  @Deprecated("this was a mistake")
   private fun <S : Any> View.takeWhileAttached(
     source: Flow<S>,
     update: (S) -> Unit