Add the KeepAnnotationsSample.

KeepAnnotationsSample/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

KeepAnnotationsSample/README.md

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+# KeepAnnotations Sample
+
+This examples shows the use of the `androidx.annotation.keep` Gradle plugin.
+
+- This programmatically generates `keep` rules when an `app` / `android library` / `java library` module uses `androidx.annotation:annotation-keep`.
+
+
+## Testing
+
+```kotlin
+
+// For app modules
+
+./gradlew <variantName>ExtractKeepRules
+
+// For android library modules
+
+./gradlew <variantName>KeepRulesTransformAar
+
+```
+
+The generated keep rules end up in `build/generated/variantName/androidx.annotation.keep.rules.pro`.

KeepAnnotationsSample/app/.gitignore

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+/build

KeepAnnotationsSample/app/build.gradle.kts

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+import kotlin.math.sign
+
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.androidx.annotation.keep)
+}
+
+android {
+    namespace = "org.example"
+    compileSdk {
+        version = release(37)
+    }
+
+    defaultConfig {
+        applicationId = "org.example"
+        minSdk = 24
+        targetSdk = 37
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            optimization {
+                enable = true
+            }
+            signingConfig = signingConfigs.getByName("debug")
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+    buildFeatures {
+        compose = true
+    }
+}
+
+dependencies {
+    implementation(libs.androidx.annotation.keep)
+    implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.activity.compose)
+    implementation(libs.androidx.compose.material3)
+    implementation(libs.androidx.compose.ui)
+    implementation(libs.androidx.compose.ui.graphics)
+    implementation(libs.androidx.compose.ui.tooling.preview)
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.lifecycle.runtime.ktx)
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.compose.ui.test.junit4)
+    androidTestImplementation(libs.androidx.espresso.core)
+    androidTestImplementation(libs.androidx.junit)
+    debugImplementation(libs.androidx.compose.ui.test.manifest)
+    debugImplementation(libs.androidx.compose.ui.tooling)
+}

KeepAnnotationsSample/app/src/androidTest/java/org/example/ExampleInstrumentedTest.kt

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+package org.example
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("org.example", appContext.packageName)
+    }
+}

KeepAnnotationsSample/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Example">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:theme="@style/Theme.Example"
+            android:windowSoftInputMode="adjustResize">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

KeepAnnotationsSample/app/src/main/java/org/example/MainActivity.kt

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+package org.example
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.tooling.preview.Preview
+import org.example.ui.theme.ExampleTheme
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContent {
+            ExampleTheme {
+                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
+                    Greeting(
+                        name = "Android",
+                        modifier = Modifier.padding(innerPadding)
+                    )
+                }
+            }
+        }
+        val locator = ResourceLocator.load()
+        println(locator)
+    }
+}
+
+@Composable
+fun Greeting(name: String, modifier: Modifier = Modifier) {
+    Text(
+        text = "Hello $name!",
+        modifier = modifier
+    )
+}
+
+@Preview(showBackground = true)
+@Composable
+fun GreetingPreview() {
+    ExampleTheme {
+        Greeting("Android")
+    }
+}

KeepAnnotationsSample/app/src/main/java/org/example/ResourceLocator.kt

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+package org.example
+
+import androidx.annotation.keep.UsesReflectionToConstruct
+
+interface ResourceLocator {
+    companion object {
+        @UsesReflectionToConstruct(classConstant = ResourceLocatorImpl::class)
+        fun load(): ResourceLocator {
+            val klass = Class.forName(ResourceLocatorImpl::class.java.name)
+            @Suppress("DEPRECATION")
+            return klass.newInstance() as ResourceLocator
+        }
+    }
+}
+
+private class ResourceLocatorImpl : ResourceLocator

KeepAnnotationsSample/app/src/main/java/org/example/ui/theme/Color.kt

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+package org.example.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple80 = Color(0xFFD0BCFF)
+val PurpleGrey80 = Color(0xFFCCC2DC)
+val Pink80 = Color(0xFFEFB8C8)
+
+val Purple40 = Color(0xFF6650a4)
+val PurpleGrey40 = Color(0xFF625b71)
+val Pink40 = Color(0xFF7D5260)

KeepAnnotationsSample/app/src/main/java/org/example/ui/theme/Theme.kt

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+package org.example.ui.theme
+
+import android.app.Activity
+import android.os.Build
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.platform.LocalContext
+
+private val DarkColorScheme = darkColorScheme(
+    primary = Purple80,
+    secondary = PurpleGrey80,
+    tertiary = Pink80
+)
+
+private val LightColorScheme = lightColorScheme(
+    primary = Purple40,
+    secondary = PurpleGrey40,
+    tertiary = Pink40
+
+    /* Other default colors to override
+    background = Color(0xFFFFFBFE),
+    surface = Color(0xFFFFFBFE),
+    onPrimary = Color.White,
+    onSecondary = Color.White,
+    onTertiary = Color.White,
+    onBackground = Color(0xFF1C1B1F),
+    onSurface = Color(0xFF1C1B1F),
+    */
+)
+
+@Composable
+fun ExampleTheme(
+    darkTheme: Boolean = isSystemInDarkTheme(),
+    // Dynamic color is available on Android 12+
+    dynamicColor: Boolean = true,
+    content: @Composable () -> Unit
+) {
+    val colorScheme = when {
+        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
+            val context = LocalContext.current
+            if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+        }
+
+        darkTheme -> DarkColorScheme
+        else -> LightColorScheme
+    }
+
+    MaterialTheme(
+        colorScheme = colorScheme,
+        typography = Typography,
+        content = content
+    )
+}

KeepAnnotationsSample/app/src/main/java/org/example/ui/theme/Type.kt

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+package org.example.ui.theme
+
+import androidx.compose.material3.Typography
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.sp
+
+// Set of Material typography styles to start with
+val Typography = Typography(
+    bodyLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 16.sp,
+        lineHeight = 24.sp,
+        letterSpacing = 0.5.sp
+    )
+    /* Other default text styles to override
+    titleLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 22.sp,
+        lineHeight = 28.sp,
+        letterSpacing = 0.sp
+    ),
+    labelSmall = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Medium,
+        fontSize = 11.sp,
+        lineHeight = 16.sp,
+        letterSpacing = 0.5.sp
+    )
+    */
+)

KeepAnnotationsSample/app/src/main/keepRules/rules.keep

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+# Add project specific R8 rules here.
+# AGP will combine all keep rule files in src/main/keepRules to pass to R8
+#
+# For more details, see
+#   https://d.android.com/r/tools/r8/keep-rules
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}