WIP performance skills testing

JetNews/app/build.gradle.kts

@@ -62,6 +62,14 @@ android {
                 "proguard-rules.pro",
             )
         }
+
+        create("benchmark") {
+            initWith(getByName("debug"))
+            isDebuggable = false
+            signingConfig = signingConfigs.getByName("debug")
+            matchingFallbacks.add("release")
+            matchingFallbacks.add("debug")
+        }
     }
     kotlin {
         compilerOptions {

JetNews/app/src/benchmark/AndroidManifest.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2026 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.
+  -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Required for macrobenchmark to write trace files on some API levels -->
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <application>
+        <profileable android:shell="true" />
+    </application>
+</manifest>

JetNews/app/src/main/java/com/example/jetnews/model/Post.kt

@@ -17,7 +17,9 @@
 package com.example.jetnews.model
 
 import androidx.annotation.DrawableRes
+import androidx.compose.runtime.Immutable
 
+@Immutable
 data class Post(
     val id: String,
     val title: String,
@@ -30,14 +32,19 @@ data class Post(
     @DrawableRes val imageThumbId: Int,
 )
 
+@Immutable
 data class Metadata(val author: PostAuthor, val date: String, val readTimeMinutes: Int)
 
+@Immutable
 data class PostAuthor(val name: String, val url: String? = null)
 
+@Immutable
 data class Publication(val name: String, val logoUrl: String)
 
+@Immutable
 data class Paragraph(val type: ParagraphType, val text: String, val markups: List<Markup> = emptyList())
 
+@Immutable
 data class Markup(val type: MarkupType, val start: Int, val end: Int, val href: String? = null)
 
 enum class MarkupType {

JetNews/app/src/main/java/com/example/jetnews/ui/home/HomeScreens.kt

@@ -37,6 +37,8 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.lazy.LazyRow
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.KeyboardActions
@@ -168,17 +170,33 @@ fun HomeScreen(
     // UiState of the HomeScreen
     val uiState by homeViewModel.uiState.collectAsStateWithLifecycle()
 
+    val onToggleFavorite = remember(homeViewModel) {
+        { postId: String -> homeViewModel.toggleFavourite(postId) }
+    }
+    val onSelectPost = remember(navigateToPost) {
+        { postId: String -> navigateToPost(postId) }
+    }
+    val onRefreshPosts = remember(homeViewModel) {
+        { homeViewModel.refreshPosts() }
+    }
+    val onErrorDismiss = remember(homeViewModel) {
+        { errorId: Long -> homeViewModel.errorShown(errorId) }
+    }
+    val onSearchInputChanged = remember(homeViewModel) {
+        { searchInput: String -> homeViewModel.onSearchInputChanged(searchInput) }
+    }
+
     HomeFeedScreen(
         uiState = uiState,
         showTopAppBar = !isExpandedScreen,
-        onToggleFavorite = { homeViewModel.toggleFavourite(it) },
-        onSelectPost = { navigateToPost(it) },
-        onRefreshPosts = { homeViewModel.refreshPosts() },
-        onErrorDismiss = { homeViewModel.errorShown(it) },
+        onToggleFavorite = onToggleFavorite,
+        onSelectPost = onSelectPost,
+        onRefreshPosts = onRefreshPosts,
+        onErrorDismiss = onErrorDismiss,
         openDrawer = openDrawer,
         homeListLazyListState = rememberLazyListState(),
         snackbarHostState = snackbarHostState,
-        onSearchInputChanged = { homeViewModel.onSearchInputChanged(it) },
+        onSearchInputChanged = onSearchInputChanged,
         searchInput = uiState.searchInput,
     )
 }
@@ -422,13 +440,14 @@ private fun PostList(
         }
         item { PostListTopSection(postsFeed.highlightedPost, onPostTapped) }
         if (postsFeed.recommendedPosts.isNotEmpty()) {
-            item {
-                PostListSimpleSection(
-                    postsFeed.recommendedPosts,
-                    onPostTapped,
-                    favorites,
-                    onToggleFavorite,
+            items(postsFeed.recommendedPosts) { post ->
+                PostCardSimple(
+                    post = post,
+                    navigateToPost = onPostTapped,
+                    isFavorite = favorites.contains(post.id),
+                    onToggleFavorite = { onToggleFavorite(post.id) }
                 )
+                PostListDivider()
             }
         }
         if (postsFeed.popularPosts.isNotEmpty() && !showExpandedSearch) {
@@ -439,7 +458,10 @@ private fun PostList(
             }
         }
         if (postsFeed.recentPosts.isNotEmpty()) {
-            item { PostListHistorySection(postsFeed.recentPosts, onPostTapped) }
+            items(postsFeed.recentPosts) { post ->
+                PostCardHistory(post, onPostTapped)
+                PostListDivider()
+            }
         }
     }
 }
@@ -478,33 +500,7 @@ private fun PostListTopSection(post: Post, navigateToPost: (String) -> Unit) {
     PostListDivider()
 }
 
-/**
- * Full-width list items for [PostList]
- *
- * @param posts (state) to display
- * @param navigateToPost (event) request navigation to Post screen
- * @param favorites (state) a set of favorite posts
- * @param onToggleFavorite (event) request that this post toggle its favorite state
- */
-@Composable
-private fun PostListSimpleSection(
-    posts: List<Post>,
-    navigateToPost: (String) -> Unit,
-    favorites: Set<String>,
-    onToggleFavorite: (String) -> Unit,
-) {
-    Column {
-        posts.forEach { post ->
-            PostCardSimple(
-                post = post,
-                navigateToPost = navigateToPost,
-                isFavorite = favorites.contains(post.id),
-                onToggleFavorite = { onToggleFavorite(post.id) },
-            )
-            PostListDivider()
-        }
-    }
-}
+
 
 /**
  * Horizontal scrolling cards for [PostList]
@@ -520,14 +516,13 @@ private fun PostListPopularSection(posts: List<Post>, navigateToPost: (String) -
             text = stringResource(id = R.string.home_popular_section_title),
             style = MaterialTheme.typography.titleLarge,
         )
-        Row(
+        LazyRow(
             modifier = Modifier
-                .horizontalScroll(rememberScrollState())
                 .height(IntrinsicSize.Max)
                 .padding(horizontal = 16.dp),
             horizontalArrangement = Arrangement.spacedBy(8.dp),
         ) {
-            for (post in posts) {
+            items(posts) { post ->
                 PostCardPopular(
                     post,
                     navigateToPost,
@@ -539,21 +534,7 @@ private fun PostListPopularSection(posts: List<Post>, navigateToPost: (String) -
     }
 }
 
-/**
- * Full-width list items that display "based on your history" for [PostList]
- *
- * @param posts (state) to display
- * @param navigateToPost (event) request navigation to Post screen
- */
-@Composable
-private fun PostListHistorySection(posts: List<Post>, navigateToPost: (String) -> Unit) {
-    Column {
-        posts.forEach { post ->
-            PostCardHistory(post, navigateToPost)
-            PostListDivider()
-        }
-    }
-}
+
 
 /**
  * Full-width divider with padding for [PostList]

JetNews/benchmark/build.gradle.kts

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2026 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.
+ */
+
+plugins {
+    alias(libs.plugins.android.test)
+}
+
+android {
+    compileSdk = libs.versions.compileSdk.get().toInt()
+    namespace = "com.example.jetnews.benchmark"
+
+    defaultConfig {
+        minSdk = 23
+        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")
+        }
+    }
+
+    targetProjectPath = ":app"
+    experimentalProperties["android.experimental.self-instrumenting"] = true
+}
+
+dependencies {
+    implementation(libs.androidx.test.rules)
+    implementation(libs.androidx.test.ext.junit)
+    implementation(libs.androidx.test.uiautomator)
+    implementation(libs.androidx.benchmark.macro.junit4)
+}

JetNews/benchmark/src/main/java/com/example/jetnews/benchmark/ExampleStartupBenchmark.kt

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2026 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.jetnews.benchmark
+
+import android.content.Intent
+import androidx.benchmark.macro.CompilationMode
+import androidx.benchmark.macro.StartupMode
+import androidx.benchmark.macro.StartupTimingMetric
+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.Until
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ExampleStartupBenchmark {
+    @get:Rule
+    val benchmarkRule = MacrobenchmarkRule()
+
+    private val targetPackageName = "com.example.jetnews"
+
+    @Test
+    fun startupCold() = benchmarkRule.measureRepeated(
+        packageName = targetPackageName,
+        metrics = listOf(StartupTimingMetric()),
+        compilationMode = CompilationMode.None(),
+        startupMode = StartupMode.COLD,
+        iterations = 5
+    ) {
+        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)
+    }
+
+    @Test
+    fun startupHot() = benchmarkRule.measureRepeated(
+        packageName = targetPackageName,
+        metrics = listOf(StartupTimingMetric()),
+        compilationMode = CompilationMode.None(),
+        startupMode = StartupMode.HOT,
+        iterations = 5
+    ) {
+        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)
+    }
+}