Delay adding SharedBounds / SharedElement

Jetsnack/app/src/main/java/com/example/jetsnack/ui/home/Feed.kt

@@ -40,6 +40,9 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.semantics.testTag
+import androidx.compose.ui.semantics.testTagsAsResourceId
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import com.example.jetsnack.model.Filter
@@ -108,7 +111,12 @@ private fun SnackCollectionList(
     sharedTransitionScope: SharedTransitionScope,
     modifier: Modifier = Modifier,
 ) {
-    LazyColumn(modifier = modifier) {
+    LazyColumn(
+        modifier = modifier.semantics {
+            testTag = "feed_list"
+            testTagsAsResourceId = true
+        },
+    ) {
         item {
             Spacer(
                 Modifier.windowInsetsTopHeight(

Jetsnack/benchmark/build.gradle.kts

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2024 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.
+ */
+
+
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.test)
+}
+
+android {
+    compileSdk = libs.versions.compileSdk.get().toInt()
+    namespace = "com.example.jetsnack.benchmark"
+
+    defaultConfig {
+        minSdk = libs.versions.minSdk.get().toInt()
+        targetSdk = libs.versions.targetSdk.get().toInt()
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        // This benchmark build type is matching the type in the target application
+        create("benchmark") {
+            signingConfig = signingConfigs.getByName("debug")
+            matchingFallbacks.add("release")
+        }
+    }
+
+    kotlin {
+        compilerOptions {
+            jvmTarget = JvmTarget.fromTarget("17")
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    targetProjectPath = ":app"
+    experimentalProperties["android.experimental.self-instrumenting"] = true
+}
+
+dependencies {
+    implementation(libs.androidx.test.rules)
+    implementation(libs.androidx.test.runner)
+    implementation(libs.androidx.test.ext.junit)
+    implementation(libs.androidx.test.uiautomator)
+    implementation(libs.androidx.benchmark.macro.junit4)
+}

Jetsnack/benchmark/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+</manifest>

Jetsnack/benchmark/src/main/java/com/example/jetsnack/benchmark/JetsnackBenchmarks.kt

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2024 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.example.jetsnack.benchmark
+
+import android.content.Intent
+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.platform.app.InstrumentationRegistry
+import androidx.test.uiautomator.By
+import androidx.test.uiautomator.Direction
+import androidx.test.uiautomator.Until
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class JetsnackBenchmarks {
+    @get:Rule
+    val benchmarkRule = MacrobenchmarkRule()
+
+    private val targetPackageName = "com.example.jetsnack"
+
+    @Test
+    fun scrollFeedFrameTiming() = benchmarkRule.measureRepeated(
+        packageName = targetPackageName,
+        metrics = listOf(FrameTimingMetric()),
+        compilationMode = CompilationMode.DEFAULT,
+        startupMode = StartupMode.COLD,
+        iterations = 10,
+        setupBlock = {
+            pressHome()
+            val context = InstrumentationRegistry.getInstrumentation().context
+            val intent = context.packageManager.getLaunchIntentForPackage(packageName)!!
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
+            context.startActivity(intent)
+            device.wait(Until.hasObject(By.pkg(packageName).depth(0)), 15000)
+            device.wait(Until.hasObject(By.res("feed_list")), 15000)
+        },
+    ) {
+        val listSelector = By.res("feed_list")
+
+        // Scroll down through feed
+        repeat(3) {
+            val list = device.findObject(listSelector) ?: device.findObject(By.scrollable(true))
+            requireNotNull(list) { "Feed list not found!" }
+            list.setGestureMargin(device.displayWidth / 5)
+            list.fling(Direction.DOWN)
+            device.waitForIdle()
+        }
+
+        // Scroll back up
+        repeat(3) {
+            val list = device.findObject(listSelector) ?: device.findObject(By.scrollable(true))
+            requireNotNull(list) { "Feed list not found!" }
+            list.setGestureMargin(device.displayWidth / 5)
+            list.fling(Direction.UP)
+            device.waitForIdle()
+        }
+    }
+
+    @Test
+    fun navigateSnackDetailFrameTiming() = benchmarkRule.measureRepeated(
+        packageName = targetPackageName,
+        metrics = listOf(FrameTimingMetric()),
+        compilationMode = CompilationMode.DEFAULT,
+        startupMode = StartupMode.COLD,
+        iterations = 10,
+        setupBlock = {
+            pressHome()
+            val context = InstrumentationRegistry.getInstrumentation().context
+            val intent = context.packageManager.getLaunchIntentForPackage(packageName)!!
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
+            context.startActivity(intent)
+            device.wait(Until.hasObject(By.pkg(packageName).depth(0)), 15000)
+            device.wait(Until.hasObject(By.res("feed_list")), 15000)
+            device.wait(Until.hasObject(By.res("highlight_snack_item")), 10000)
+            device.waitForIdle()
+        },
+    ) {
+        val listSelector = By.res("feed_list")
+
+        // Find snack item to click and trigger shared element transition
+        val snackItem = device.wait(Until.findObject(By.text("Cupcake")), 10000)
+            ?: device.wait(Until.findObject(By.text("Donut")), 5000)
+            ?: device.wait(Until.findObject(By.res("highlight_snack_item")), 5000)
+            ?: device.findObject(By.res("snack_item"))
+            ?: device.findObject(By.clickable(true))
+        requireNotNull(snackItem) { "Snack item not found on feed!" }
+
+        // Click snack to navigate into detail with shared element transition
+        snackItem.click()
+
+        // Wait for detail screen to appear
+        val detailLoaded = device.wait(Until.hasObject(By.desc("Back")), 10000) ||
+            device.wait(Until.hasObject(By.text("Details")), 5000) ||
+            device.wait(Until.hasObject(By.textContains("CART")), 5000)
+        check(detailLoaded) { "Detail screen not loaded!" }
+        device.waitForIdle()
+
+        // Return to feed with reverse shared transition
+        device.pressBack()
+        device.wait(Until.hasObject(listSelector), 10000)
+        device.waitForIdle()
+    }
+}

Jetsnack/build.gradle.kts

@@ -18,6 +18,7 @@ plugins {
     alias(libs.plugins.gradle.versions)
     alias(libs.plugins.version.catalog.update)
     alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.android.test) apply false
     alias(libs.plugins.kotlin.parcelize) apply false
     alias(libs.plugins.compose) apply false
     alias(libs.plugins.spotless) apply false

Jetsnack/gradle/libs.versions.toml

@@ -4,6 +4,7 @@ android-material3 = "1.14.0"
 androidGradlePlugin = "9.3.1"
 androidx-activity-compose = "1.13.0"
 androidx-appcompat = "1.8.0"
+androidx-benchmark = "1.3.3"
 androidx-compose-bom = "2026.08.00"
 androidx-core-splashscreen = "1.2.0"
 androidx-corektx = "1.19.0"
@@ -110,6 +111,7 @@ androidx-test-ext-truth = { module = "androidx.test.ext:truth", version.ref = "a
 androidx-test-rules = { module = "androidx.test:rules", version.ref = "androidx-test" }
 androidx-test-runner = { module = "androidx.test:runner", version.ref = "androidx-test" }
 androidx-test-uiautomator = { module = "androidx.test.uiautomator:uiautomator", version.ref = "androix-test-uiautomator" }
+androidx-benchmark-macro-junit4 = { module = "androidx.benchmark:benchmark-macro-junit4", version.ref = "androidx-benchmark" }
 androidx-tv-foundation = { module = "androidx.tv:tv-foundation", version.ref = "androidx-tv-foundation" }
 androidx-tv-material = { module = "androidx.tv:tv-material", version.ref = "androidx-tv-material" }
 androidx-wear-compose-foundation = { module = "androidx.wear.compose:compose-foundation", version.ref = "androidx-wear-compose" }

Jetsnack/settings.gradle.kts

@@ -38,3 +38,4 @@ dependencyResolutionManagement {
 }
 rootProject.name = "Jetsnack"
 include(":app")
+include(":benchmark")