Add a new project for DataStore

datastore/.gitignore

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+/build

datastore/build.gradle.kts

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+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.compose.compiler)
+
+    // [START android_datastore_proto_plugin]
+    alias(libs.plugins.google.protobuf)
+    // [END android_datastore_proto_plugin]
+
+    // [START android_datastore_serialization_plugin]
+    alias(libs.plugins.kotlin.serialization)
+    // [END android_datastore_serialization_plugin]
+}
+
+android {
+    namespace = "com.example.datastore.snippets"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "com.example.datastore.snippets"
+        minSdk = 23
+        targetSdk = 36
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+    kotlinOptions {
+        jvmTarget = "11"
+    }
+    buildFeatures {
+        compose = true
+    }
+}
+
+dependencies {
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.lifecycle.runtime)
+    implementation(libs.androidx.activity.compose)
+    implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.compose.ui)
+    implementation(libs.androidx.compose.ui.graphics)
+    implementation(libs.androidx.compose.ui.tooling.preview)
+    implementation(libs.androidx.compose.material3)
+
+    // [START android_datastore_dependency]
+    // Typed DataStore (Typed API surface, such as Proto)
+    implementation(libs.androidx.datastore)
+
+    // Alternatively - without an Android dependency.
+    implementation(libs.androidx.datastore.core)
+    // [END android_datastore_dependency]
+
+    // [START android_datastore_preferences_dependency]
+    // Preferences DataStore (SharedPreferences like APIs)
+    implementation(libs.androidx.datastore.preferences)
+
+    // Alternatively - without an Android dependency.
+    implementation(libs.androidx.datastore.preferences.core)
+    // [END android_datastore_preferences_dependency]
+
+    // [START android_datastore_preferences_dependency_rxjava]
+    // optional - RxJava2 support
+    implementation(libs.androidx.datastore.preferences.rxjava2)
+
+    // optional - RxJava3 support
+    implementation(libs.androidx.datastore.preferences.rxjava3)
+    // [END android_datastore_preferences_dependency_rxjava]
+
+    implementation(libs.androidx.navigation3.ui)
+    implementation(libs.androidx.navigation3.runtime)
+
+    // [START android_datastore_proto_dependency]
+    implementation(libs.google.protobuf.kotlin.lite)
+    // [END android_datastore_proto_dependency]
+
+    // [START android_datastore_json_dependency]
+    implementation(libs.kotlinx.serialization.json)
+    // [END android_datastore_json_dependency]
+
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.test.ext.junit)
+    androidTestImplementation(libs.androidx.test.espresso.core)
+    androidTestImplementation(platform(libs.androidx.compose.bom))
+    androidTestImplementation(libs.androidx.compose.ui.test.junit4)
+    debugImplementation(libs.androidx.compose.ui.tooling)
+    debugImplementation(libs.androidx.compose.ui.test.manifest)
+}
+
+// [START android_datastore_proto_task]
+protobuf {
+    protoc {
+        artifact = "com.google.protobuf:protoc:4.32.1"
+    }
+    generateProtoTasks {
+        all().forEach { task ->
+            task.builtins {
+                create("java") {
+                    option("lite")
+                }
+                create("kotlin")
+            }
+        }
+    }
+}
+// [END android_datastore_proto_task]

datastore/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# 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 *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

datastore/src/androidTest/java/com/example/datastore/snippets/DataStoreSnippetsTest.kt

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+/*
+ * Copyright 2025 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.datastore.snippets
+
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.example.datastore.snippets.json.JsonDataStoreScreen
+import com.example.datastore.snippets.multiprocess.MultiProcessDataStoreScreen
+import com.example.datastore.snippets.preferences.PreferencesDataStoreScreen
+import com.example.datastore.snippets.proto.ProtoDataStoreScreen
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class DataStoreSnippetsTest {
+    @get:Rule
+    val rule = createComposeRule()
+
+    @Test
+    fun launchPreferencesDataStore() {
+        rule.setContent { PreferencesDataStoreScreen() }
+        rule.onNodeWithText("Preferences DataStore").assertExists()
+    }
+
+    @Test
+    fun launchProtoDataStore() {
+        rule.setContent { ProtoDataStoreScreen() }
+        rule.onNodeWithText("Proto DataStore").assertExists()
+    }
+
+    @Test
+    fun launchJsonDataStore() {
+        rule.setContent { JsonDataStoreScreen() }
+        rule.onNodeWithText("Json DataStore").assertExists()
+    }
+
+    @Test
+    fun launchMultiProcessDataStore() {
+        rule.setContent { MultiProcessDataStoreScreen() }
+        rule.onNodeWithText("Multi-process DataStore").assertExists()
+    }
+}

datastore/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright 2025 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">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Snippets">
+        <!-- // [START android_datastore_multiprocess_manifest] -->
+        <service
+            android:name=".TimestampUpdateService"
+            android:process=":my_process_id" />
+        <!-- // [END android_datastore_multiprocess_manifest] -->
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:theme="@style/Theme.Snippets">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

datastore/src/main/java/com/example/datastore/snippets/Home.kt

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+/*
+ * Copyright 2025 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.datastore.snippets
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+
+@Composable
+internal fun Home(backStack: MutableList<MainActivity.Snippets>) {
+    Column {
+        Item("Preferences Data Store") {
+            backStack.add(MainActivity.Snippets.PreferencesDataStore)
+        }
+        Item("Proto Data Store") {
+            backStack.add(MainActivity.Snippets.ProtoDataStore)
+        }
+        Item("Json Data Store") {
+            backStack.add(MainActivity.Snippets.JsonDataStore)
+        }
+        Item("Multi process Data Store") {
+            backStack.add(MainActivity.Snippets.MultiProcessDataStore)
+        }
+    }
+}
+
+@Composable
+private fun Item(text: String, onClick: () -> Unit) {
+    Box(
+        Modifier
+            .fillMaxWidth()
+            .clickable(onClick = onClick)
+            .padding(10.dp)
+    ) {
+        Text(fontSize = 30.sp, text = text)
+    }
+}