BREAKING: Stop stomping View.layoutParams, new parameter for `repla…

…ceViewInParent`

`WorkflowViewStub.replaceViewInParent` now can be configured not to propagate `layoutParams`, by setting new property `propagatesLayoutParams` to `false`. When it's `true` (the default), the stub's `layoutParams` are passed as a new third argument to the (customizable) `replaceViewInParent` function, to make it clearer that this function bears responsibility for applying them.

Motivated because `BodyAndOverlaysContainer` and `WorkflowLayout` were being dictatorial about the body view's layout params for no clear reason, leading to layout surprises. They're the first to opt out of `propagatesLayoutParams`.

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

@@ -270,13 +270,15 @@ public final class com/squareup/workflow1/ui/WorkflowViewStub : android/view/Vie
 	public synthetic fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;IIILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun getActual ()Landroid/view/View;
 	public final fun getInflatedId ()I
-	public final fun getReplaceOldViewInParent ()Lkotlin/jvm/functions/Function2;
+	public final fun getPropagatesLayoutParams ()Z
+	public final fun getReplaceOldViewInParent ()Lkotlin/jvm/functions/Function3;
 	public final fun getUpdatesVisibility ()Z
 	public fun getVisibility ()I
 	public fun setBackground (Landroid/graphics/drawable/Drawable;)V
 	public fun setId (I)V
 	public final fun setInflatedId (I)V
-	public final fun setReplaceOldViewInParent (Lkotlin/jvm/functions/Function2;)V
+	public final fun setPropagatesLayoutParams (Z)V
+	public final fun setReplaceOldViewInParent (Lkotlin/jvm/functions/Function3;)V
 	public final fun setUpdatesVisibility (Z)V
 	public fun setVisibility (I)V
 	public final fun show (Lcom/squareup/workflow1/ui/Screen;Lcom/squareup/workflow1/ui/ViewEnvironment;)V

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

@@ -20,7 +20,6 @@ import com.squareup.workflow1.ui.container.EnvironmentScreen
  *    by ScreenViewFactory(
  *      buildView = { environment, context, _ ->
  *        val view = MyBackStackContainer(context)
- *          .apply { layoutParams = (LayoutParams(MATCH_PARENT, MATCH_PARENT)) }
  *        ScreenViewHolder(environment, view) { rendering, environment ->
  *          view.update(rendering, environment)
  *        }

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

@@ -8,8 +8,6 @@ import android.os.Parcelable.Creator
 import android.util.AttributeSet
 import android.util.SparseArray
 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.Lifecycle.State
@@ -51,7 +49,8 @@ public class WorkflowLayout(
 
   private val showing: WorkflowViewStub = WorkflowViewStub(context).also { rootStub ->
     rootStub.updatesVisibility = false
-    addView(rootStub, ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT))
+    rootStub.propagatesLayoutParams = false
+    addView(rootStub)
   }
 
   private var restoredChildState: SparseArray<Parcelable>? = null

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

@@ -5,6 +5,7 @@ import android.graphics.drawable.Drawable
 import android.util.AttributeSet
 import android.view.View
 import android.view.ViewGroup
+import android.view.ViewGroup.LayoutParams
 import androidx.annotation.IdRes
 import androidx.savedstate.SavedStateRegistryOwner
 import androidx.savedstate.findViewTreeSavedStateRegistryOwner
@@ -85,6 +86,14 @@ public class WorkflowViewStub @JvmOverloads constructor(
    */
   public var updatesVisibility: Boolean = true
 
+  /**
+   * If true, the [layoutParams][getLayoutParams] of this stub will be applied
+   * to new views as they are added to the stub's original parent.
+   * Specifically, the third parameter passed to [replaceOldViewInParent]
+   * will be non-null.
+   */
+  public var propagatesLayoutParams: Boolean = true
+
   /**
    * The id to be assigned to new views created by [update]. If the inflated id is
    * [View.NO_ID] (its default value), new views keep their original ids.
@@ -121,15 +130,19 @@ public class WorkflowViewStub @JvmOverloads constructor(
   /**
    * Function called from [update] to replace this stub, or the current [actual],
    * with a new view. Can be updated to provide custom transition effects.
+   * The default implementation simply calls [ViewGroup.addView], including
+   * the `layoutParams` parameter if it is non-null.
    *
-   * Note that this method is responsible for copying the [layoutParams][getLayoutParams]
-   * from the stub to the new view. Also note that in a [WorkflowViewStub] that has never
-   * been updated, [actual] is the stub itself.
+   * @see propagatesLayoutParams
    */
-  public var replaceOldViewInParent: (ViewGroup, View) -> Unit = { parent, newView ->
+  public var replaceOldViewInParent: (
+    parent: ViewGroup,
+    newView: View,
+    layoutParams: LayoutParams?
+  ) -> Unit = { parent, newView, layoutParams ->
     val index = parent.indexOfChild(actual)
     parent.removeView(actual)
-    actual.layoutParams
+    layoutParams
       ?.let { parent.addView(newView, index, it) }
       ?: run { parent.addView(newView, index) }
   }
@@ -241,7 +254,7 @@ public class WorkflowViewStub @JvmOverloads constructor(
         if (updatesVisibility) newView.visibility = visibility
         background?.let { newView.background = it }
         propagateSavedStateRegistryOwner(newView)
-        replaceOldViewInParent(parent, newView)
+        replaceOldViewInParent(parent, newView, layoutParams?.takeIf { propagatesLayoutParams })
       }
   }
 

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

@@ -9,7 +9,6 @@ import android.os.Parcelable.Creator
 import android.util.AttributeSet
 import android.view.KeyEvent
 import android.view.MotionEvent
-import android.view.ViewGroup
 import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.widget.FrameLayout
 import com.squareup.workflow1.ui.Compatible
@@ -42,8 +41,9 @@ internal class BodyAndOverlaysContainer @JvmOverloads constructor(
    */
   private lateinit var savedStateParentKey: String
 
-  private val baseViewStub: WorkflowViewStub = WorkflowViewStub(context).also {
-    addView(it, ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT))
+  private val baseViewStub: WorkflowViewStub = WorkflowViewStub(context).apply {
+    propagatesLayoutParams = false
+    addView(this)
   }
 
   private val dialogs = LayeredDialogSessions.forView(