Merge pull request #7 from square/zachklipp/compose-nesting

Add the ability to display nested renderings with bindCompose.

Author: zach-klippenstein

build.gradle.kts

@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import org.jetbrains.dokka.gradle.DokkaTask
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import org.jlleitschuh.gradle.ktlint.KtlintExtension
 import org.jlleitschuh.gradle.ktlint.reporter.ReporterType
@@ -38,6 +37,9 @@ buildscript {
   }
 }
 
+// See https://stackoverflow.com/questions/25324880/detect-ide-environment-with-gradle
+val isRunningFromIde get() = project.properties["android.injected.invoked.from.ide"] == "true"
+
 subprojects {
   repositories {
     google()
@@ -60,7 +62,10 @@ subprojects {
 
   tasks.withType<KotlinCompile>() {
     kotlinOptions {
-      kotlinOptions.allWarningsAsErrors = true
+      // Allow warnings when running from IDE, makes it easier to experiment.
+      if (!isRunningFromIde) {
+        allWarningsAsErrors = true
+      }
 
       jvmTarget = "1.8"
 

core-compose/api/core-compose.api

@@ -21,6 +21,11 @@ public final class com/squareup/workflow/ui/compose/ComposeViewFactory : com/squ
 	public fun getType ()Lkotlin/reflect/KClass;
 }
 
+public final class com/squareup/workflow/ui/compose/ViewEnvironmentsKt {
+	public static final fun showRendering (Lcom/squareup/workflow/ui/ViewEnvironment;Ljava/lang/Object;Landroidx/ui/core/Modifier;Landroidx/compose/Composer;)V
+	public static synthetic fun showRendering$default (Lcom/squareup/workflow/ui/ViewEnvironment;Ljava/lang/Object;Landroidx/ui/core/Modifier;Landroidx/compose/Composer;ILjava/lang/Object;)V
+}
+
 public final class com/squareup/workflow/ui/core/compose/BuildConfig {
 	public static final field BUILD_TYPE Ljava/lang/String;
 	public static final field DEBUG Z

core-compose/src/main/java/com/squareup/workflow/ui/compose/ComposeViewFactory.kt

@@ -56,17 +56,30 @@ import kotlin.reflect.KClass
  *
  * val viewRegistry = ViewRegistry(FooBinding, …)
  * ```
+ *
+ * ## Nesting child renderings
+ *
+ * Workflows can render other workflows, and renderings from one workflow can contain renderings
+ * from other workflows. These renderings may all be bound to their own [ViewFactory]s. Regular
+ * [ViewFactory]s and `LayoutRunner`s use
+ * [WorkflowViewStub][com.squareup.workflow.ui.WorkflowViewStub] to recursively show nested
+ * renderings using the [ViewRegistry][com.squareup.workflow.ui.ViewRegistry].
+ *
+ * View factories defined using this function may also show nested renderings. Doing so is as simple
+ * as calling [ViewEnvironment.showRendering] and passing in the nested rendering. See the kdoc on
+ * that function for an example.
  */
 inline fun <reified RenderingT : Any> bindCompose(
-  noinline showRendering: @Composable() (RenderingT, ViewEnvironment) -> Unit
-): ViewFactory<RenderingT> = ComposeViewFactory(RenderingT::class) { rendering, environment ->
-  showRendering(rendering, environment)
-}
+  noinline showRendering: @Composable() (
+    rendering: RenderingT,
+    environment: ViewEnvironment
+  ) -> Unit
+): ViewFactory<RenderingT> = ComposeViewFactory(RenderingT::class, showRendering)
 
 @PublishedApi
 internal class ComposeViewFactory<RenderingT : Any>(
   override val type: KClass<RenderingT>,
-  private val showRendering: @Composable() (RenderingT, ViewEnvironment) -> Unit
+  internal val showRendering: @Composable() (RenderingT, ViewEnvironment) -> Unit
 ) : ViewFactory<RenderingT> {
 
   override fun buildView(

core-compose/src/main/java/com/squareup/workflow/ui/compose/ViewEnvironments.kt

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2020 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.workflow.ui.compose
+
+import androidx.compose.Composable
+import androidx.compose.remember
+import androidx.ui.core.Modifier
+import com.squareup.workflow.ui.ViewEnvironment
+import com.squareup.workflow.ui.ViewRegistry
+
+/**
+ * Renders [rendering] into the composition using this [ViewEnvironment]'s
+ * [ViewRegistry][com.squareup.workflow.ui.ViewRegistry] to generate the view.
+ *
+ * This function fulfills a similar role as
+ * [WorkflowViewStub][com.squareup.workflow.ui.WorkflowViewStub], but is much more convenient to use
+ * from Composable functions.
+ *
+ * ## Example
+ *
+ * ```
+ * data class FramedRendering(
+ *   val borderColor: Color,
+ *   val child: Any
+ * )
+ *
+ * val FramedContainerViewFactory = bindCompose<FramedRendering> { rendering, environment ->
+ *   Surface(border = Border(rendering.borderColor, 8.dp)) {
+ *     environment.showRendering(rendering.child)
+ *   }
+ * }
+ * ```
+ *
+ * @param rendering The workflow rendering to display. May be of any type for which a
+ * [ViewFactory][com.squareup.workflow.ui.ViewFactory] has been registered in this
+ * environment's [ViewRegistry].
+ * @param modifier A [Modifier] that will be applied to composable used to show [rendering].
+ *
+ * @throws IllegalArgumentException if no factory can be found for [rendering]'s type.
+ */
+@Composable fun ViewEnvironment.showRendering(
+  rendering: Any,
+  modifier: Modifier = Modifier
+) {
+  val viewRegistry = remember(this) { this[ViewRegistry] }
+  viewRegistry.showRendering(rendering, this, modifier)
+}

core-compose/src/main/java/com/squareup/workflow/ui/compose/ViewFactories.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2020 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.workflow.ui.compose
+
+import android.content.Context
+import android.view.ViewGroup.LayoutParams.MATCH_PARENT
+import android.widget.FrameLayout
+import androidx.compose.Composable
+import androidx.ui.core.Modifier
+import androidx.ui.foundation.Box
+import com.squareup.workflow.ui.ViewEnvironment
+import com.squareup.workflow.ui.ViewFactory
+import com.squareup.workflow.ui.WorkflowViewStub
+import com.squareup.workflow.ui.compose.ComposableViewStubWrapper.Update
+
+/**
+ * Renders [rendering] into the composition using the `ViewRegistry` from the [ViewEnvironment] to
+ * determine how to draw it.
+ *
+ * To display a nested rendering from a [Composable view binding][bindCompose], use
+ * [ViewEnvironment.showRendering].
+ *
+ * @see ViewEnvironment.showRendering
+ * @see com.squareup.workflow.ui.ViewRegistry.showRendering
+ */
+// Bug: IR compiler pukes on ViewFactory<RenderingT> here.
+@Composable internal fun <RenderingT : Any> ViewFactory<Any>.showRendering(
+  rendering: RenderingT,
+  viewEnvironment: ViewEnvironment,
+  modifier: Modifier = Modifier
+) {
+  Box(modifier = modifier) {
+    // Fast path: If the child binding is also a Composable, we don't need to go through the legacy
+    // view system and can just invoke the binding's composable function directly.
+    if (this is ComposeViewFactory) {
+      showRendering(rendering, viewEnvironment)
+    } else {
+      // IntelliJ currently complains very loudly about this function call, but it actually compiles.
+      // The IDE tooling isn't currently able to recognize that the Compose compiler accepts this code.
+      ComposableViewStubWrapper(update = Update(rendering, viewEnvironment))
+    }
+  }
+}
+
+/**
+ * Wraps a [WorkflowViewStub] with an API that is more Compose-friendly.
+ *
+ * In particular, Compose will only generate `Emittable`s for views with a single constructor
+ * that takes a [Context].
+ *
+ * See [this slack message](https://kotlinlang.slack.com/archives/CJLTWPH7S/p1576264533012000?thread_ts=1576262311.008800&cid=CJLTWPH7S).
+ */
+private class ComposableViewStubWrapper(context: Context) : FrameLayout(context) {
+
+  data class Update(
+    val rendering: Any,
+    val viewEnvironment: ViewEnvironment
+  )
+
+  private val viewStub = WorkflowViewStub(context)
+
+  init {
+    addView(viewStub)
+  }
+
+  // Compose turns this into a parameter when you invoke this class as a Composable.
+  fun setUpdate(update: Update) {
+    viewStub.update(update.rendering, update.viewEnvironment)
+  }
+
+  override fun getLayoutParams(): LayoutParams = LayoutParams(MATCH_PARENT, MATCH_PARENT)
+}

core-compose/src/main/java/com/squareup/workflow/ui/compose/ViewRegistries.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020 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.workflow.ui.compose
+
+import androidx.compose.Composable
+import androidx.compose.remember
+import androidx.ui.core.Modifier
+import com.squareup.workflow.ui.ViewEnvironment
+import com.squareup.workflow.ui.ViewFactory
+import com.squareup.workflow.ui.ViewRegistry
+
+/**
+ * Renders [rendering] into the composition using this [ViewRegistry] to determine how to draw it.
+ *
+ * To display a nested rendering from a [Composable view binding][bindCompose], use
+ * [ViewEnvironment.showRendering].
+ *
+ * @see ViewEnvironment.showRendering
+ * @see ViewFactory.showRendering
+ */
+@Composable internal fun ViewRegistry.showRendering(
+  rendering: Any,
+  hints: ViewEnvironment,
+  modifier: Modifier = Modifier
+) {
+  val renderingType = rendering::class
+  val viewFactory = remember(renderingType) { getFactoryFor(renderingType) }
+  viewFactory.showRendering(rendering, hints, modifier)
+}

samples/nested-renderings/build.gradle.kts

@@ -0,0 +1,48 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+/*
+ * Copyright 2020 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.
+ */
+plugins {
+  id("com.android.application")
+  kotlin("android")
+}
+
+apply(from = rootProject.file(".buildscript/android-sample-app.gradle"))
+apply(from = rootProject.file(".buildscript/android-ui-tests.gradle"))
+
+android {
+  defaultConfig {
+    applicationId = "com.squareup.sample.nestedrenderings"
+  }
+}
+
+apply(from = rootProject.file(".buildscript/configure-compose.gradle"))
+tasks.withType<KotlinCompile> {
+  kotlinOptions.apiVersion = "1.3"
+}
+
+dependencies {
+  implementation(project(":core-compose"))
+  implementation(Dependencies.AndroidX.appcompat)
+  implementation(Dependencies.Compose.foundation)
+  implementation(Dependencies.Compose.layout)
+  implementation(Dependencies.Compose.material)
+  implementation(Dependencies.Workflow.UI.coreAndroid)
+
+  androidTestImplementation(Dependencies.Compose.test)
+  androidTestImplementation(Dependencies.Test.junit)
+  androidTestImplementation(Dependencies.Test.truth)
+}

samples/nested-renderings/src/androidTest/java/com/squareup/sample/nestedrenderings/NestedRenderingsTest.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2020 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.sample.nestedrenderings
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.ui.test.android.AndroidComposeTestRule
+import androidx.ui.test.assertIsDisplayed
+import androidx.ui.test.doClick
+import androidx.ui.test.findAllByText
+import androidx.ui.test.findByText
+import com.google.common.truth.Truth.assertThat
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+private const val ADD_BUTTON_TEXT = "Add Child"
+
+@RunWith(AndroidJUnit4::class)
+class NestedRenderingsTest {
+
+  // Launches the activity.
+  @Rule @JvmField val composeRule = AndroidComposeTestRule<NestedRenderingsActivity>()
+
+  @Test fun childrenAreAddedAndRemoved() {
+    val resetButton = findByText("Reset")
+
+    findByText(ADD_BUTTON_TEXT)
+        .assertIsDisplayed()
+        .doClick()
+
+    findAllByText(ADD_BUTTON_TEXT)
+        .also { addButtons ->
+          assertThat(addButtons).hasSize(2)
+          addButtons.forEach { it.doClick() }
+        }
+
+    findAllByText(ADD_BUTTON_TEXT)
+        .also { addButtons ->
+          assertThat(addButtons).hasSize(4)
+        }
+
+    resetButton.doClick()
+    assertThat(findAllByText(ADD_BUTTON_TEXT)).hasSize(1)
+  }
+}