Migrate View Row+Column away from subtype (#2442)

When widgets switch to abstract classes, this will no longer be allowed.

redwood-layout-view/src/main/kotlin/app/cash/redwood/layout/view/ViewFlexContainer.kt

@@ -27,8 +27,13 @@ import androidx.core.widget.NestedScrollView
 import androidx.core.widget.NestedScrollView.OnScrollChangeListener as OnScrollChangeListenerCompat
 import app.cash.redwood.Modifier
 import app.cash.redwood.layout.api.Constraint
+import app.cash.redwood.layout.api.CrossAxisAlignment
+import app.cash.redwood.layout.api.MainAxisAlignment
 import app.cash.redwood.layout.api.Overflow
+import app.cash.redwood.layout.widget.Column
+import app.cash.redwood.layout.widget.Row
 import app.cash.redwood.ui.Density
+import app.cash.redwood.ui.Margin
 import app.cash.redwood.ui.Px
 import app.cash.redwood.widget.ChangeListener
 import app.cash.redwood.widget.ViewGroupChildren
@@ -37,6 +42,46 @@ import app.cash.redwood.yoga.FlexDirection
 import app.cash.redwood.yoga.Node
 import app.cash.redwood.yoga.isHorizontal
 
+internal class ViewColumn(context: Context) :
+  Column<View>,
+  ChangeListener {
+  private val delegate = ViewFlexContainer(context, FlexDirection.Column)
+
+  override val value get() = delegate.value
+  override var modifier by delegate::modifier
+
+  override val children get() = delegate.children
+
+  override fun width(width: Constraint) = delegate.width(width)
+  override fun height(height: Constraint) = delegate.height(height)
+  override fun margin(margin: Margin) = delegate.margin(margin)
+  override fun overflow(overflow: Overflow) = delegate.overflow(overflow)
+  override fun horizontalAlignment(horizontalAlignment: CrossAxisAlignment) = delegate.crossAxisAlignment(horizontalAlignment)
+  override fun verticalAlignment(verticalAlignment: MainAxisAlignment) = delegate.mainAxisAlignment(verticalAlignment)
+  override fun onScroll(onScroll: ((Px) -> Unit)?) = delegate.onScroll(onScroll)
+  override fun onEndChanges() = delegate.onEndChanges()
+}
+
+internal class ViewRow(context: Context) :
+  Row<View>,
+  ChangeListener {
+  private val delegate = ViewFlexContainer(context, FlexDirection.Row)
+
+  override val value get() = delegate.value
+  override var modifier by delegate::modifier
+
+  override val children get() = delegate.children
+
+  override fun width(width: Constraint) = delegate.width(width)
+  override fun height(height: Constraint) = delegate.height(height)
+  override fun margin(margin: Margin) = delegate.margin(margin)
+  override fun overflow(overflow: Overflow) = delegate.overflow(overflow)
+  override fun horizontalAlignment(horizontalAlignment: MainAxisAlignment) = delegate.mainAxisAlignment(horizontalAlignment)
+  override fun verticalAlignment(verticalAlignment: CrossAxisAlignment) = delegate.crossAxisAlignment(verticalAlignment)
+  override fun onScroll(onScroll: ((Px) -> Unit)?) = delegate.onScroll(onScroll)
+  override fun onEndChanges() = delegate.onEndChanges()
+}
+
 internal class ViewFlexContainer(
   private val context: Context,
   private val direction: FlexDirection,
@@ -73,7 +118,7 @@ internal class ViewFlexContainer(
     },
   )
 
-  private var onScroll: ((Px) -> Unit)? = null
+  internal var onScroll: ((Px) -> Unit)? = null
 
   override var modifier: Modifier = Modifier
 

redwood-layout-view/src/main/kotlin/app/cash/redwood/layout/view/ViewRedwoodLayoutWidgetFactory.kt

@@ -22,16 +22,15 @@ import app.cash.redwood.layout.widget.Column
 import app.cash.redwood.layout.widget.RedwoodLayoutWidgetFactory
 import app.cash.redwood.layout.widget.Row
 import app.cash.redwood.layout.widget.Spacer
-import app.cash.redwood.yoga.FlexDirection
 
 public class ViewRedwoodLayoutWidgetFactory(
   private val context: Context,
 ) : RedwoodLayoutWidgetFactory<View> {
   override fun Box(): Box<View> = ViewBox(context)
 
-  override fun Column(): Column<View> = ViewFlexContainer(context, FlexDirection.Column)
+  override fun Column(): Column<View> = ViewColumn(context)
 
-  override fun Row(): Row<View> = ViewFlexContainer(context, FlexDirection.Row)
+  override fun Row(): Row<View> = ViewRow(context)
 
   override fun Spacer(): Spacer<View> = ViewSpacer(context)
 }

redwood-layout-view/src/test/kotlin/app/cash/redwood/layout/view/ViewFlexContainerTest.kt

@@ -21,6 +21,10 @@ import app.cash.paparazzi.DeviceConfig
 import app.cash.paparazzi.Paparazzi
 import app.cash.redwood.layout.AbstractFlexContainerTest
 import app.cash.redwood.layout.TestFlexContainer
+import app.cash.redwood.layout.api.Constraint
+import app.cash.redwood.layout.api.Overflow
+import app.cash.redwood.layout.widget.Column
+import app.cash.redwood.layout.widget.Row
 import app.cash.redwood.layout.widget.Spacer
 import app.cash.redwood.snapshot.testing.ViewSnapshotter
 import app.cash.redwood.snapshot.testing.ViewTestWidgetFactory
@@ -57,9 +61,15 @@ class ViewFlexContainerTest(
       .apply { (this as TestFlexContainer<*>).applyDefaults() }
   }
 
-  override fun row() = flexContainer(FlexDirection.Row)
+  override fun row(): Row<View> = ViewRow(paparazzi.context).apply {
+    value.setBackgroundColor(defaultBackgroundColor)
+    applyDefaults()
+  }
 
-  override fun column() = flexContainer(FlexDirection.Column)
+  override fun column(): Column<View> = ViewColumn(paparazzi.context).apply {
+    value.setBackgroundColor(defaultBackgroundColor)
+    applyDefaults()
+  }
 
   override fun spacer(backgroundColor: Int): Spacer<View> {
     return ViewSpacer(paparazzi.context)
@@ -75,16 +85,18 @@ class ViewFlexContainerTest(
   ) : TestFlexContainer<View>,
     YogaFlexContainer<View> by delegate,
     ChangeListener by delegate {
-    private var onScroll: ((Px) -> Unit)? = null
+    override val value: View get() = delegate.value
+    override var modifier by delegate::modifier
 
     override val children: ViewGroupChildren = delegate.children
 
-    override fun onScroll(onScroll: ((Px) -> Unit)?) {
-      this.onScroll = onScroll
-    }
+    override fun width(width: Constraint) = delegate.width(width)
+    override fun height(height: Constraint) = delegate.height(height)
+    override fun overflow(overflow: Overflow) = delegate.overflow(overflow)
+    override fun onScroll(onScroll: ((Px) -> Unit)?) = delegate.onScroll(onScroll)
 
     override fun scroll(offset: Px) {
-      onScroll?.invoke(offset)
+      delegate.onScroll?.invoke(offset)
     }
   }
 }