Merge pull request #380 from android/ben/topics_recomposition

Allow InterestsItem to be skipped on recomposition

benchmark/src/main/java/com/google/samples/apps/nowinandroid/interests/InterestsActions.kt

@@ -19,6 +19,7 @@ package com.google.samples.apps.nowinandroid.interests
 import androidx.benchmark.macro.MacrobenchmarkScope
 import androidx.test.uiautomator.By
 import androidx.test.uiautomator.Direction
+import androidx.test.uiautomator.Until
 
 fun MacrobenchmarkScope.interestsScrollTopicsDownUp() {
     val topicsList = device.findObject(By.res("interests:topics"))
@@ -33,3 +34,14 @@ fun MacrobenchmarkScope.interestsScrollPeopleDownUp() {
     device.waitForIdle()
     peopleList.fling(Direction.UP)
 }
+
+fun MacrobenchmarkScope.interestsWaitForTopics() {
+    device.wait(Until.hasObject(By.text("Accessibility")), 30_000)
+}
+
+fun MacrobenchmarkScope.interestsToggleBookmarked() {
+    val topicsList = device.findObject(By.res("interests:topics"))
+    val checkable = topicsList.findObject(By.checkable(true))
+    checkable.click()
+    device.waitForIdle()
+}

benchmark/src/main/java/com/google/samples/apps/nowinandroid/interests/TopicsScreenRecompositionBenchmark.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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.google.samples.apps.nowinandroid.interests
+
+import androidx.benchmark.macro.CompilationMode
+import androidx.benchmark.macro.FrameTimingMetric
+import androidx.benchmark.macro.StartupMode
+import androidx.benchmark.macro.junit4.MacrobenchmarkRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.uiautomator.By
+import com.google.samples.apps.nowinandroid.PACKAGE_NAME
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class TopicsScreenRecompositionBenchmark {
+    @get:Rule
+    val benchmarkRule = MacrobenchmarkRule()
+
+    @Test
+    fun benchmarkStateChangeCompilationBaselineProfile() =
+        benchmarkStateChange(CompilationMode.Partial())
+
+    private fun benchmarkStateChange(compilationMode: CompilationMode) =
+        benchmarkRule.measureRepeated(
+            packageName = PACKAGE_NAME,
+            metrics = listOf(FrameTimingMetric()),
+            compilationMode = compilationMode,
+            iterations = 10,
+            startupMode = StartupMode.WARM,
+            setupBlock = {
+                // Start the app
+                pressHome()
+                startActivityAndWait()
+
+                // Navigate to interests screen
+                device.findObject(By.text("Interests")).click()
+                device.waitForIdle()
+            }
+        ) {
+            interestsWaitForTopics()
+            repeat(3) {
+                interestsToggleBookmarked()
+            }
+        }
+}

feature/interests/src/main/java/com/google/samples/apps/nowinandroid/feature/interests/TabContent.kt

@@ -46,14 +46,15 @@ fun TopicsTabContent(
         contentPadding = PaddingValues(top = 8.dp)
     ) {
         topics.forEach { followableTopic ->
-            item {
+            val topicId = followableTopic.topic.id
+            item(key = topicId) {
                 InterestsItem(
                     name = followableTopic.topic.name,
                     following = followableTopic.isFollowed,
                     description = followableTopic.topic.shortDescription,
                     topicImageUrl = followableTopic.topic.imageUrl,
-                    onClick = { onTopicClick(followableTopic.topic.id) },
-                    onFollowButtonClick = { onFollowButtonClick(followableTopic.topic.id, it) }
+                    onClick = { onTopicClick(topicId) },
+                    onFollowButtonClick = { onFollowButtonClick(topicId, it) }
                 )
             }
         }