square · rjrjr · Oct 1, 2020 · Oct 1, 2020
@@ -24,7 +24,6 @@ import com.squareup.sample.container.overviewdetail.OverviewDetailConfig.Overvie
 import com.squareup.sample.container.overviewdetail.OverviewDetailConfig.Single
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.LayoutRunner
-import com.squareup.workflow1.ui.LayoutRunnerViewFactory
 import com.squareup.workflow1.ui.ViewFactory
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowViewStub
@@ -98,9 +97,8 @@ class OverviewDetailContainer(view: View) : LayoutRunner<OverviewDetailScreen> {
     stub.update(combined, viewEnvironment + (OverviewDetailConfig to Single))
   }
 
-  companion object : ViewFactory<OverviewDetailScreen> by LayoutRunnerViewFactory(
-      type = OverviewDetailScreen::class,
+  companion object : ViewFactory<OverviewDetailScreen> by LayoutRunner.bind(
       layoutId = R.layout.overview_detail,
-      runnerConstructor = ::OverviewDetailContainer
+      constructor = ::OverviewDetailContainer
   )
 }
@@ -105,18 +105,13 @@ public abstract interface class com/squareup/workflow1/ui/ViewRegistry {
 	public static final field Companion Lcom/squareup/workflow1/ui/ViewRegistry$Companion;
 	public abstract fun getFactoryFor (Lkotlin/reflect/KClass;)Lcom/squareup/workflow1/ui/ViewFactory;
 	public abstract fun getKeys ()Ljava/util/Set;
-	public abstract fun hasViewBeenBound (Landroid/view/View;)Z
 }
 
 public final class com/squareup/workflow1/ui/ViewRegistry$Companion : com/squareup/workflow1/ui/ViewEnvironmentKey {
 	public fun getDefault ()Lcom/squareup/workflow1/ui/ViewRegistry;
 	public synthetic fun getDefault ()Ljava/lang/Object;
 }
 
-public final class com/squareup/workflow1/ui/ViewRegistry$DefaultImpls {
-	public static fun hasViewBeenBound (Lcom/squareup/workflow1/ui/ViewRegistry;Landroid/view/View;)Z
-}
-
 public final class com/squareup/workflow1/ui/ViewRegistryKt {
 	public static final fun ViewRegistry ()Lcom/squareup/workflow1/ui/ViewRegistry;
 	public static final fun ViewRegistry ([Lcom/squareup/workflow1/ui/ViewFactory;)Lcom/squareup/workflow1/ui/ViewRegistry;

@@ -1,18 +1,3 @@
-/*
- * Copyright 2019 Square Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
 package com.squareup.workflow1.ui
 
 import android.content.Context
@@ -32,54 +17,8 @@ typealias ViewBindingInflater<BindingT> = (LayoutInflater, ViewGroup?, Boolean)
  * by a [ViewRegistry]. (Use [BuilderViewFactory] if you want to build views from code rather
  * than layouts.)
  *
- * Typical usage is to have a [LayoutRunner]'s `companion object` implement
- * [ViewFactory] by delegating to [LayoutRunner.bind], specifying the layout resource
- * it expects to drive.
- *
- *   class HelloLayoutRunner(view: View) : LayoutRunner<Rendering> {
- *     private val messageView: TextView = view.findViewById(R.id.hello_message)
- *
- *     override fun showRendering(rendering: Rendering) {
- *       messageView.text = rendering.message
- *       messageView.setOnClickListener { rendering.onClick(Unit) }
- *     }
- *
- *     companion object : ViewFactory<Rendering> by bind(
- *         R.layout.hello_goodbye_layout, ::HelloLayoutRunner
- *     )
- *   }
- *
- * This pattern allows us to assemble a [ViewRegistry] out of the [LayoutRunner] classes
- * themselves.
- *
- *    val TicTacToeViewBuilders = ViewRegistry(
- *        NewGameLayoutRunner, GamePlayLayoutRunner, GameOverLayoutRunner
- *    )
- *
- * ## AndroidX ViewBinding
- *
- * [AndroidX ViewBinding][ViewBinding] is supported in two ways.
- * In most cases, you can use the `bind` function that takes a function and avoid implementing
- * [LayoutRunner] at all.
- *
- * If you need to perform some set up before [showRendering] is called, use the
- * `bind` overload that takes:
- *  - a reference to a `ViewBinding.inflate` method and
- *  - a [LayoutRunner] constructor that accepts a [ViewBinding]
- *
- *   class HelloLayoutRunner(private val binding: HelloGoodbyeLayoutBinding) : LayoutRunner<Rendering> {
- *
- *     override fun showRendering(rendering: Rendering) {
- *       binding.messageView.text = rendering.message
- *       binding.messageView.setOnClickListener { rendering.onClick(Unit) }
- *     }
- *
- *     companion object : ViewFactory<Rendering> by bind(
- *         HelloGoodbyeLayoutBinding::inflate, ::HelloLayoutRunner
- *     )
- *   }
- *
- * If the view does not need to be initialized, the [bind] function can be used instead.
+ * If you're using [AndroidX ViewBinding][ViewBinding] you likely won't need to
+ * implement this interface at all. For details, see the three overloads of [LayoutRunner.bind].
  */
 @WorkflowUiExperimentalApi
 interface LayoutRunner<RenderingT : Any> {
@@ -90,28 +29,18 @@ interface LayoutRunner<RenderingT : Any> {
 
   companion object {
     /**
-     * Creates a [ViewFactory] that inflates [layoutId] to show renderings of type [RenderingT],
-     * using a [LayoutRunner] created by [constructor].
-     */
-    inline fun <reified RenderingT : Any> bind(
-      @LayoutRes layoutId: Int,
-      noinline constructor: (View) -> LayoutRunner<RenderingT>
-    ): ViewFactory<RenderingT> = LayoutRunnerViewFactory(RenderingT::class, layoutId, constructor)
-
-    /**
-     * Creates a [ViewFactory] that [inflates][bindingInflater] a [ViewBinding] ([BindingT]) to show
-     * renderings of type [RenderingT], using [showRendering].
+     * Creates a [ViewFactory] that [inflates][bindingInflater] a [ViewBinding] ([BindingT])
+     * to show renderings of type [RenderingT], using [a lambda][showRendering].
      *
-     * ```
-     * val HelloBinding: ViewFactory<Rendering> =
-     *   bindViewBinding(HelloGoodbyeLayoutBinding::inflate) { rendering, viewEnvironment ->
-     *     helloMessage.text = rendering.message
-     *     helloMessage.setOnClickListener { rendering.onClick(Unit) }
-     *   }
-     * ```
+     *    val HelloBinding: ViewFactory<Rendering> =
+     *      LayoutRunner.bind(HelloGoodbyeLayoutBinding::inflate) { rendering, viewEnvironment ->
+     *        helloMessage.text = rendering.message
+     *        helloMessage.setOnClickListener { rendering.onClick(Unit) }
+     *      }
      *
-     * If you need to initialize your view before [showRendering] is called, create a [LayoutRunner]
-     * and create a binding using `LayoutRunner.bind` instead.
+     * If you need to initialize your view before [showRendering] is called,
+     * implement [LayoutRunner] and create a binding using the `bind` variant
+     * that accepts a `(ViewBinding) -> LayoutRunner` function, below.
      */
     inline fun <BindingT : ViewBinding, reified RenderingT : Any> bind(
       noinline bindingInflater: ViewBindingInflater<BindingT>,
@@ -126,22 +55,46 @@ interface LayoutRunner<RenderingT : Any> {
     }
 
     /**
-     * Creates a [ViewFactory] that [inflates][bindingInflater] a [BindingT] to show renderings of
-     * type [RenderingT], using a [LayoutRunner] created by [constructor].
+     * Creates a [ViewFactory] that [inflates][bindingInflater] a [ViewBinding] ([BindingT])
+     * to show renderings of type [RenderingT], using a [LayoutRunner] created by [constructor].
+     * Handy if you need to perform some set up before [showRendering] is called.
+     *
+     *   class HelloLayoutRunner(
+     *     private val binding: HelloGoodbyeLayoutBinding
+     *   ) : LayoutRunner<Rendering> {
+     *
+     *     override fun showRendering(rendering: Rendering) {
+     *       binding.messageView.text = rendering.message
+     *       binding.messageView.setOnClickListener { rendering.onClick(Unit) }
+     *     }
+     *
+     *     companion object : ViewFactory<Rendering> by bind(
+     *         HelloGoodbyeLayoutBinding::inflate, ::HelloLayoutRunner
+     *     )
+     *   }
      *
      * If the view doesn't need to be initialized before [showRendering] is called,
-     * [bind] can be used instead, which just takes a lambda instead requiring a whole
-     * [LayoutRunner] class.
+     * use the variant above which just takes a lambda.
      */
     inline fun <BindingT : ViewBinding, reified RenderingT : Any> bind(
       noinline bindingInflater: ViewBindingInflater<BindingT>,
       noinline constructor: (BindingT) -> LayoutRunner<RenderingT>
     ): ViewFactory<RenderingT> =
       ViewBindingViewFactory(RenderingT::class, bindingInflater, constructor)
 
+    /**
+     * Creates a [ViewFactory] that inflates [layoutId] to show renderings of type [RenderingT],
+     * using a [LayoutRunner] created by [constructor]. Avoids any use of
+     * [AndroidX ViewBinding][ViewBinding].
+     */
+    inline fun <reified RenderingT : Any> bind(
+      @LayoutRes layoutId: Int,
+      noinline constructor: (View) -> LayoutRunner<RenderingT>
+    ): ViewFactory<RenderingT> = LayoutRunnerViewFactory(RenderingT::class, layoutId, constructor)
+
     /**
      * Creates a [ViewFactory] that inflates [layoutId] to "show" renderings of type [RenderingT],
-     * with a no-op [LayoutRunner]. Handy for showing static views.
+     * with a no-op [LayoutRunner]. Handy for showing static views, e.g. when prototyping.
      */
     inline fun <reified RenderingT : Any> bindNoRunner(
       @LayoutRes layoutId: Int

@@ -12,7 +12,8 @@ import kotlin.reflect.KClass
  * details.
  */
 @WorkflowUiExperimentalApi
-class LayoutRunnerViewFactory<RenderingT : Any>(
+@PublishedApi
+internal class LayoutRunnerViewFactory<RenderingT : Any>(
   override val type: KClass<RenderingT>,
   @LayoutRes private val layoutId: Int,
   private val runnerConstructor: (View) -> LayoutRunner<RenderingT>

@@ -34,10 +34,10 @@ internal val defaultViewFactories = ViewRegistry(NamedViewFactory)
  *
  * Two concrete [ViewFactory] implementations are provided:
  *
- *  - [LayoutRunner.Binding], allowing the easy pairing of Android XML layout resources with
- *    [LayoutRunner]s to drive them.
+ *  - The various [bind][LayoutRunner.bind] methods on [LayoutRunner] allow easy use of
+ *    Android XML layout resources and [AndroidX ViewBinding][androidx.viewbinding.ViewBinding].
  *
- *  - [BuilderViewFactory], which can build views from code.
+ *  - [BuilderViewFactory] allows views to be built from code.
  *
  *  Registries can be assembled via concatenation, making it easy to snap together screen sets.
  *  For example:
@@ -54,8 +54,7 @@ internal val defaultViewFactories = ViewRegistry(NamedViewFactory)
  *         AuthViewFactories + TicTacToeViewFactories
  *
  * In the above example, note that the `companion object`s of the various [LayoutRunner] classes
- * honor a convention of implementing [ViewFactory], in aid of this kind of assembly. See the
- * class doc on [LayoutRunner] for details.
+ * honor a convention of implementing [ViewFactory], in aid of this kind of assembly.
  */
 @WorkflowUiExperimentalApi
 interface ViewRegistry {
@@ -79,14 +78,6 @@ interface ViewRegistry {
     renderingType: KClass<out RenderingT>
   ): ViewFactory<RenderingT>
 
-  /**
-   * This method is not for general use, it's called by [buildView] to validate views returned by
-   * [ViewFactory]s.
-   *
-   * Returns true iff [view] has been bound to a [ShowRenderingTag] by calling [bindShowRendering].
-   */
-  fun hasViewBeenBound(view: View): Boolean = view.getRendering<Any>() != null
-
   companion object : ViewEnvironmentKey<ViewRegistry>(ViewRegistry::class) {
     override val default: ViewRegistry
       get() = error("There should always be a ViewRegistry hint, this is bug in Workflow.")
@@ -118,8 +109,8 @@ fun ViewRegistry(): ViewRegistry = TypedViewRegistry()
  *
  * @throws IllegalArgumentException if no factory can be find for type [RenderingT]
  *
- * @throws IllegalStateException if [ViewRegistry.hasViewBeenBound] returns false (i.e. if the
- * matching [ViewFactory] fails to call [View.bindShowRendering] when constructing the view)
+ * @throws IllegalStateException if the matching [ViewFactory] fails to call
+ * [View.bindShowRendering] when constructing the view
  */
 @WorkflowUiExperimentalApi
 fun <RenderingT : Any> ViewRegistry.buildView(
@@ -136,7 +127,7 @@ fun <RenderingT : Any> ViewRegistry.buildView(
           container
       )
       .apply {
-        check(hasViewBeenBound(this)) {
+        check(this.getRendering<Any>() != null) {
           "View.bindShowRendering should have been called for $this, typically by the " +
               "${ViewFactory::class.java.name} that created it."
         }