snapshot of https://github.com/flutter/samples.git (main, 2026-09-16; blobs > 131072B omitted)

add_to_app/books/android_books/.gitignore

@@ -0,0 +1,14 @@
+*.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

add_to_app/books/android_books/README.md

@@ -0,0 +1,14 @@
+# android_books
+
+An example Android application used in the Flutter add-to-app samples. For more
+information on how to use it, see the [README](../README.md) file located in the
+[/add_to_app](/add_to_app) directory of this repo.
+
+## Getting Started
+
+For more information about Flutter, check out
+[flutter.dev](https://flutter.dev).
+
+For instructions on how to integrate Flutter modules into your existing
+applications, see Flutter's
+[add-to-app documentation](https://flutter.dev/docs/development/add-to-app).

add_to_app/books/android_books/app/.gitignore

@@ -0,0 +1 @@
+/build

add_to_app/books/android_books/app/build.gradle

@@ -0,0 +1,53 @@
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion 31
+    buildToolsVersion "29.0.3"
+
+    defaultConfig {
+        applicationId "dev.flutter.example.books"
+        minSdkVersion 21
+        targetSdkVersion 29
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        profile {
+            initWith debug
+        }
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+            signingConfig debug.signingConfig
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: "libs", include: ["*.jar"])
+    implementation "com.squareup.okhttp3:okhttp:4.7.2"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation 'androidx.core:core-ktx:1.3.0'
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation "androidx.activity:activity-ktx:1.1.0"
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    implementation 'com.google.android.material:material:1.1.0'
+    implementation 'com.google.code.gson:gson:2.8.6'
+    implementation project(path: ':flutter')
+    testImplementation 'junit:junit:4.13'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+
+}

add_to_app/books/android_books/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# 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

add_to_app/books/android_books/app/src/androidTest/java/dev/flutter/example/books/ExampleInstrumentedTest.kt

@@ -0,0 +1,27 @@
+package dev.flutter.example.books
+
+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 MainActivityTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("dev.flutter.example.books", appContext.packageName)
+    }
+
+    // The app should be hermetic (with offline books JSON) before adding
+    // more tests.
+}

add_to_app/books/android_books/app/src/main/AndroidManifest.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="dev.flutter.example.books">
+
+    <application
+        android:name=".BookApplication"
+        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/AppTheme">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+        <activity
+            android:name=".FlutterBookActivity"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize" />
+    </application>
+    <uses-permission android:name="android.permission.INTERNET" />
+
+</manifest>

add_to_app/books/android_books/app/src/main/java/dev/flutter/example/books/Api.java

@@ -0,0 +1,252 @@
+// Autogenerated from Pigeon (v1.0.1), do not edit directly.
+// See also: https://pub.dev/packages/pigeon
+
+package dev.flutter.example.books;
+
+import io.flutter.plugin.common.BasicMessageChannel;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.MessageCodec;
+import io.flutter.plugin.common.StandardMessageCodec;
+import java.io.ByteArrayOutputStream;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/** Generated class from Pigeon. */
+@SuppressWarnings(
+    {"unused", "unchecked", "CodeBlock2Expr", "RedundantSuppression"})
+public class Api {
+
+  /** Generated class from Pigeon that represents data sent in messages. */
+  public static class Book {
+    private String title;
+    public String getTitle() { return title; }
+    public void setTitle(String setterArg) { this.title = setterArg; }
+
+    private String subtitle;
+    public String getSubtitle() { return subtitle; }
+    public void setSubtitle(String setterArg) { this.subtitle = setterArg; }
+
+    private String author;
+    public String getAuthor() { return author; }
+    public void setAuthor(String setterArg) { this.author = setterArg; }
+
+    private String summary;
+    public String getSummary() { return summary; }
+    public void setSummary(String setterArg) { this.summary = setterArg; }
+
+    private String publishDate;
+    public String getPublishDate() { return publishDate; }
+    public void setPublishDate(String setterArg) {
+      this.publishDate = setterArg;
+    }
+
+    private Long pageCount;
+    public Long getPageCount() { return pageCount; }
+    public void setPageCount(Long setterArg) { this.pageCount = setterArg; }
+
+    private Thumbnail thumbnail;
+    public Thumbnail getThumbnail() { return thumbnail; }
+    public void setThumbnail(Thumbnail setterArg) {
+      this.thumbnail = setterArg;
+    }
+
+    Map<String, Object> toMap() {
+      Map<String, Object> toMapResult = new HashMap<>();
+      toMapResult.put("title", title);
+      toMapResult.put("subtitle", subtitle);
+      toMapResult.put("author", author);
+      toMapResult.put("summary", summary);
+      toMapResult.put("publishDate", publishDate);
+      toMapResult.put("pageCount", pageCount);
+      toMapResult.put("thumbnail",
+                      (thumbnail == null) ? null : thumbnail.toMap());
+      return toMapResult;
+    }
+    static Book fromMap(Map<String, Object> map) {
+      Book fromMapResult = new Book();
+      Object title = map.get("title");
+      fromMapResult.title = (String)title;
+      Object subtitle = map.get("subtitle");
+      fromMapResult.subtitle = (String)subtitle;
+      Object author = map.get("author");
+      fromMapResult.author = (String)author;
+      Object summary = map.get("summary");
+      fromMapResult.summary = (String)summary;
+      Object publishDate = map.get("publishDate");
+      fromMapResult.publishDate = (String)publishDate;
+      Object pageCount = map.get("pageCount");
+      fromMapResult.pageCount =
+          (pageCount == null)
+              ? null
+              : ((pageCount instanceof Integer) ? (Integer)pageCount
+                                                : (Long)pageCount);
+      Object thumbnail = map.get("thumbnail");
+      fromMapResult.thumbnail = Thumbnail.fromMap((Map)thumbnail);
+      return fromMapResult;
+    }
+  }
+
+  /** Generated class from Pigeon that represents data sent in messages. */
+  public static class Thumbnail {
+    private String url;
+    public String getUrl() { return url; }
+    public void setUrl(String setterArg) { this.url = setterArg; }
+
+    Map<String, Object> toMap() {
+      Map<String, Object> toMapResult = new HashMap<>();
+      toMapResult.put("url", url);
+      return toMapResult;
+    }
+    static Thumbnail fromMap(Map<String, Object> map) {
+      Thumbnail fromMapResult = new Thumbnail();
+      Object url = map.get("url");
+      fromMapResult.url = (String)url;
+      return fromMapResult;
+    }
+  }
+  private static class FlutterBookApiCodec extends StandardMessageCodec {
+    public static final FlutterBookApiCodec INSTANCE =
+        new FlutterBookApiCodec();
+    private FlutterBookApiCodec() {}
+    @Override
+    protected Object readValueOfType(byte type, ByteBuffer buffer) {
+      switch (type) {
+      case (byte)128:
+        return Book.fromMap((Map<String, Object>)readValue(buffer));
+
+      default:
+        return super.readValueOfType(type, buffer);
+      }
+    }
+    @Override
+    protected void writeValue(ByteArrayOutputStream stream, Object value) {
+      if (value instanceof Book) {
+        stream.write(128);
+        writeValue(stream, ((Book)value).toMap());
+      } else {
+        super.writeValue(stream, value);
+      }
+    }
+  }
+
+  /**
+   * Generated class from Pigeon that represents Flutter messages that can be
+   * called from Java.
+   */
+  public static class FlutterBookApi {
+    private final BinaryMessenger binaryMessenger;
+    public FlutterBookApi(BinaryMessenger argBinaryMessenger) {
+      this.binaryMessenger = argBinaryMessenger;
+    }
+    public interface Reply<T> {
+      void reply(T reply);
+    }
+    static MessageCodec<Object> getCodec() {
+      return FlutterBookApiCodec.INSTANCE;
+    }
+
+    public void displayBookDetails(Book bookArg, Reply<Void> callback) {
+      BasicMessageChannel<Object> channel = new BasicMessageChannel<>(
+          binaryMessenger,
+          "dev.flutter.pigeon.FlutterBookApi.displayBookDetails", getCodec());
+      channel.send(new ArrayList<Object>(Arrays.asList(bookArg)),
+                   channelReply -> { callback.reply(null); });
+    }
+  }
+  private static class HostBookApiCodec extends StandardMessageCodec {
+    public static final HostBookApiCodec INSTANCE = new HostBookApiCodec();
+    private HostBookApiCodec() {}
+    @Override
+    protected Object readValueOfType(byte type, ByteBuffer buffer) {
+      switch (type) {
+      case (byte)128:
+        return Book.fromMap((Map<String, Object>)readValue(buffer));
+
+      default:
+        return super.readValueOfType(type, buffer);
+      }
+    }
+    @Override
+    protected void writeValue(ByteArrayOutputStream stream, Object value) {
+      if (value instanceof Book) {
+        stream.write(128);
+        writeValue(stream, ((Book)value).toMap());
+      } else {
+        super.writeValue(stream, value);
+      }
+    }
+  }
+
+  /**
+   * Generated interface from Pigeon that represents a handler of messages from
+   * Flutter.
+   */
+  public interface HostBookApi {
+    void cancel();
+    void finishEditingBook(Book book);
+
+    /** The codec used by HostBookApi. */
+    static MessageCodec<Object> getCodec() { return HostBookApiCodec.INSTANCE; }
+
+    /**
+     * Sets up an instance of `HostBookApi` to handle messages through the
+     * `binaryMessenger`.
+     */
+    static void setup(BinaryMessenger binaryMessenger, HostBookApi api) {
+      {
+        BasicMessageChannel<Object> channel = new BasicMessageChannel<>(
+            binaryMessenger, "dev.flutter.pigeon.HostBookApi.cancel",
+            getCodec());
+        if (api != null) {
+          channel.setMessageHandler((message, reply) -> {
+            Map<String, Object> wrapped = new HashMap<>();
+            try {
+              api.cancel();
+              wrapped.put("result", null);
+            } catch (Error | RuntimeException exception) {
+              wrapped.put("error", wrapError(exception));
+            }
+            reply.reply(wrapped);
+          });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
+      {
+        BasicMessageChannel<Object> channel = new BasicMessageChannel<>(
+            binaryMessenger, "dev.flutter.pigeon.HostBookApi.finishEditingBook",
+            getCodec());
+        if (api != null) {
+          channel.setMessageHandler((message, reply) -> {
+            Map<String, Object> wrapped = new HashMap<>();
+            try {
+              ArrayList<Object> args = (ArrayList<Object>)message;
+              Book bookArg = (Book)args.get(0);
+              if (bookArg == null) {
+                throw new NullPointerException("bookArg unexpectedly null.");
+              }
+              api.finishEditingBook(bookArg);
+              wrapped.put("result", null);
+            } catch (Error | RuntimeException exception) {
+              wrapped.put("error", wrapError(exception));
+            }
+            reply.reply(wrapped);
+          });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
+    }
+  }
+  private static Map<String, Object> wrapError(Throwable exception) {
+    Map<String, Object> errorMap = new HashMap<>();
+    errorMap.put("message", exception.toString());
+    errorMap.put("code", exception.getClass().getSimpleName());
+    errorMap.put("details", null);
+    return errorMap;
+  }
+}

add_to_app/books/android_books/app/src/main/java/dev/flutter/example/books/BookApplication.kt

@@ -0,0 +1,28 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package dev.flutter.example.books
+
+import android.app.Application
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.embedding.engine.FlutterEngineCache
+import io.flutter.embedding.engine.dart.DartExecutor
+
+class BookApplication: Application() {
+    companion object {
+        const val ENGINE_ID = "book_engine"
+    }
+
+    private lateinit var flutterEngine: FlutterEngine
+
+    override fun onCreate() {
+        super.onCreate()
+        // This application reuses a single FlutterEngine instance throughout.
+        // Create the FlutterEngine on application start.
+        flutterEngine = FlutterEngine(this).apply{
+            dartExecutor.executeDartEntrypoint(DartExecutor.DartEntrypoint.createDefault())
+        }
+        FlutterEngineCache.getInstance().put(ENGINE_ID, flutterEngine)
+    }
+}

add_to_app/books/android_books/app/src/main/java/dev/flutter/example/books/FlutterBookActivity.kt

@@ -0,0 +1,101 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package dev.flutter.example.books
+
+import android.app.Activity
+import android.content.Context
+import android.content.Intent
+import dev.flutter.example.books.BookApplication.Companion.ENGINE_ID
+import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+import java.util.HashMap
+
+/**
+ * This {@link FlutterActivity} class repackages Kotlin-Dart interop using the Pigeon IPC mechanism.
+ * It repackages Flutter/Dart-side functionalities in standard Android API style, passing
+ * arguments in and out of the activity using 'startActivityForResult' intents and
+ * 'onActivityResult' intents.
+ */
+class FlutterBookActivity: FlutterActivity() {
+    companion object {
+        const val EXTRA_BOOK = "book"
+
+        /**
+         * Static intent factory to start {@link FlutterBookActivity} with the singleton
+         * {@link FlutterEngine} the application started.
+         *
+         * The activity launched from this intent shows the details of the {@link Api.Book}
+         * supplied.
+         */
+        fun withBook(context: Context, book: Api.Book): Intent {
+            // In a more realistic app, there should be some dependency injection mechanism to
+            // determine which engine to use.
+            return CachedEngineBookIntentBuilder(ENGINE_ID)
+                .build(context)
+                .putExtra(
+                    // The Pigeon data class is useful not only between Kotlin/Java and Dart
+                    // but also within Kotlin/Java where activities must communicate with
+                    // each other via serializable data. The Pigeon data class is a
+                    // serializable class by definition.
+                    EXTRA_BOOK,
+                    // TODO(gaaclarke): the Pigeon generated data class should just implement
+                    // Serializable so we won't need 'toMap()' here
+                    // https://github.com/flutter/flutter/issues/58909
+                    HashMap(book.toMap())
+                )
+        }
+
+        /**
+         *  A static helper method to parse a result intent from this activity into a {@link Book}.
+         *
+         * @param resultIntent an {@link Intent} that must be the data intent returned by this
+         *                     activity's {@code onActivityResult}.
+         */
+        fun getBookFromResultIntent(resultIntent: Intent): Api.Book {
+            return Api.Book.fromMap((resultIntent.getSerializableExtra(FlutterBookActivity.EXTRA_BOOK) as HashMap<String, Any>));
+        }
+    }
+
+    // Intent builder class to build a FlutterBookActivity instance instead of the default FlutterActivity.
+    class CachedEngineBookIntentBuilder(engineId: String): CachedEngineIntentBuilder(FlutterBookActivity::class.java, engineId) { }
+
+    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+        // Called shortly after the activity is created, when the activity is bound to a
+        // FlutterEngine responsible for rendering the Flutter activity's content.
+        super.configureFlutterEngine(flutterEngine)
+
+        // The book to give to Flutter is passed in from the MainActivity via this activity's
+        // source intent getter. The intent contains the book serialized as on extra.
+        val bookToShow = Api.Book.fromMap(intent.getSerializableExtra(EXTRA_BOOK) as HashMap<String, Any>)
+
+        // Register the HostBookApiHandler callback class to get results from Flutter.
+        Api.HostBookApi.setup(flutterEngine.dartExecutor, HostBookApiHandler())
+
+        // Send in the book instance to Flutter.
+        Api.FlutterBookApi(flutterEngine.dartExecutor).displayBookDetails(bookToShow) {
+            // We don't care about the callback
+        }
+    }
+
+    // This {@link Api.HostBookApi} subclass will be called by Pigeon when the corresponding
+    // APIs are invoked on the Dart side.
+    inner class HostBookApiHandler: Api.HostBookApi {
+        override fun cancel() {
+            // Flutter called cancel. Finish the activity with a cancel result.
+            setResult(Activity.RESULT_CANCELED)
+            finish()
+        }
+
+        override fun finishEditingBook(book: Api.Book?) {
+            if (book == null) {
+                throw IllegalArgumentException("finishedEditingBook cannot be called with a null argument")
+            }
+            // Flutter returned an edited book instance. Return it to the MainActivity via the
+            // standard Android Activity set result mechanism.
+            setResult(Activity.RESULT_OK, Intent().putExtra(EXTRA_BOOK, HashMap(book.toMap())))
+            finish()
+        }
+    }
+}

add_to_app/books/android_books/app/src/main/java/dev/flutter/example/books/MainActivity.kt

@@ -0,0 +1,169 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package dev.flutter.example.books
+
+import android.app.Activity
+import android.content.Intent
+import androidx.appcompat.app.AppCompatActivity
+import android.os.Bundle
+import android.view.View
+import android.widget.LinearLayout
+import android.widget.ProgressBar
+import android.widget.TextView
+import com.google.android.material.button.MaterialButton
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonParser
+import okhttp3.Call
+import okhttp3.Callback
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.Response
+import java.io.IOException
+import java.lang.Exception
+import java.lang.RuntimeException
+
+class MainActivity : AppCompatActivity() {
+    companion object {
+        const val BOOKS_QUERY = "https://www.googleapis.com/books/v1/volumes?q=greenwood+tulsa&maxResults=15"
+    }
+
+    private lateinit var books: MutableList<Api.Book>
+    private lateinit var list: LinearLayout
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+        list = findViewById<LinearLayout>(R.id.list)
+
+        // OkHttp is arbitrarily chosen here to represent an existing middleware constraint that's
+        // already present in an existing application's infrastructure.
+        val httpClient = OkHttpClient()
+        val bookRequest = Request.Builder()
+            // Retrieve data from Google Books API (arbitrarily chosen). This represents existing
+            // data sources that an existing application is already interfacing with.
+            .url(BOOKS_QUERY)
+            .build()
+
+        httpClient.newCall(bookRequest).enqueue(object : Callback {
+            override fun onFailure(call: Call, e: IOException) {
+                throw e
+            }
+
+            override fun onResponse(call: Call, response: Response) {
+                response.use {
+                    if (!response.isSuccessful) throw IOException("Unexpected code $response")
+                    books = parseGoogleBooksJsonToBooks(response.body!!.string())
+
+                    val spinner = findViewById<ProgressBar>(R.id.spinner)
+
+                    runOnUiThread {
+                        // Showed a spinner while network call is in progress. Remove it when
+                        // response is received.
+                        spinner.visibility = View.GONE
+                        populateBookCards()
+                    }
+                }
+            }
+        })
+    }
+
+    // Take a top level Google Books query's response JSON and create a list of Book Pigeon data
+    // classes that will be used both as a model here on the Kotlin side and also in the IPCs
+    // to Dart.
+    private fun parseGoogleBooksJsonToBooks(jsonBody: String): MutableList<Api.Book> {
+        // Here we're arbitrarily using GSON to represent another existing middleware constraint
+        // that already exists in your existing application's infrastructure.
+        val jsonBooks = JsonParser.parseString(jsonBody).asJsonObject.getAsJsonArray("items")
+        val books = mutableListOf<Api.Book>()
+        for (jsonBook in jsonBooks.map { it.asJsonObject }) {
+            try {
+                // Here we're using GSON to populate a Pigeon data class directly. The Pigeon data
+                // class can be used not just as part of your IPC API's signature but also as a
+                // normal data class in your existing application.
+                //
+                // We could either push the Pigeon data class usage higher into the existing GSON
+                // "middleware" or lower, closer to the IPC.
+                val book = Api.Book()
+                val volumeInfoJson = jsonBook.getAsJsonObject("volumeInfo")
+                book.title = volumeInfoJson.get("title").asString
+                book.subtitle = volumeInfoJson.get("subtitle")?.asString
+                // Sorry co-authors, we're trying to keep this simple.
+                book.author = volumeInfoJson.getAsJsonArray("authors")[0].asString
+                book.summary = volumeInfoJson.get("description").asString
+                book.publishDate = volumeInfoJson.get("publishedDate").asString
+                book.pageCount = volumeInfoJson.get("pageCount").asLong
+                val thumbnail = Api.Thumbnail()
+                thumbnail.url = volumeInfoJson.getAsJsonObject("imageLinks").get("thumbnail").asString
+                book.thumbnail = thumbnail
+                books.add(book)
+            } catch (e: Exception) {
+                println("Failed to parse book:")
+                println(GsonBuilder().setPrettyPrinting().create().toJson(jsonBook))
+                println("Parsing error:")
+                println(e)
+            }
+        }
+        return books
+    }
+
+    // Given a populated books list, create a Material Design card in a scroll view for each book.
+    private fun populateBookCards() {
+        for ((index, book) in books.withIndex()) {
+            val card = layoutInflater.inflate(R.layout.book_card, null)
+            updateCardWithBook(card, book)
+            card.findViewById<MaterialButton>(R.id.edit).setOnClickListener {
+                // When the edit button is clicked in a book's card, launch a Flutter activity
+                // showing the details of the book.
+                startActivityForResult(
+                    // We're using our own 'FlutterActivity' subclass which wraps Pigeon API usages
+                    // into an idiomatic Android activity interface with intent extras as input and
+                    // with activity 'setResult' as output.
+                    //
+                    // This lets activity-level feature developers abstract their Flutter usage
+                    // and present a standard Android API to their upstream application developers.
+                    //
+                    // No Flutter-specific concepts are leaked outside the Flutter activity itself
+                    // into the consuming class.
+                    FlutterBookActivity
+                        // Re-read from the 'books' list rather than just capturing the iterated
+                        // 'book' instance since we change it when Dart updates it in onActivityResult.
+                        .withBook(this, books[index]),
+                    // The index lets us know which book we're returning the result for when we
+                    // return from the Flutter activity.
+                    index)
+            }
+            list.addView(card)
+        }
+    }
+
+    // Given a Material Design card and a book, update the card content to reflect the book model.
+    private fun updateCardWithBook(card: View, book: Api.Book) {
+        card.findViewById<TextView>(R.id.title).text = book.title
+        card.findViewById<TextView>(R.id.subtitle).text = book.subtitle
+        card.findViewById<TextView>(R.id.author).text = resources.getString(R.string.author_prefix, book.author)
+    }
+
+    // Callback when the Flutter activity started with 'startActivityForResult' above returns.
+    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+        super.onActivityResult(requestCode, resultCode, data)
+
+        // The Flutter activity may cancel the edit. If so, don't update anything.
+        if (resultCode == Activity.RESULT_OK) {
+            if (data == null) {
+                throw RuntimeException("The FlutterBookActivity returning RESULT_OK should always have a return data intent")
+            }
+
+            // If the book was edited in Flutter, the Flutter activity finishes and returns an
+            // activity result in an intent (the 'data' argument). The intent has an extra which is
+            // the edited book in serialized form.
+            val returnedBook = FlutterBookActivity.getBookFromResultIntent(data)
+            // Update our book model list.
+            books[requestCode] = returnedBook
+
+            // Refresh the UI here on the Kotlin side.
+            updateCardWithBook(list.getChildAt(requestCode), returnedBook)
+        }
+    }
+}

add_to_app/books/android_books/app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

add_to_app/books/android_books/app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#3DDC84"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>

add_to_app/books/android_books/app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <com.google.android.material.appbar.AppBarLayout
+        android:id="@+id/appbar"
+        app:liftOnScroll="true"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <androidx.core.widget.NestedScrollView
+        android:id="@+id/nestedScrollView"
+        android:layout_width="match_parent"
+
+
+        android:layout_height="match_parent"
+        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
+
+        <LinearLayout
+            android:id="@+id/list"
+            android:orientation="vertical"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            tools:context=".MainActivity" />
+
+    </androidx.core.widget.NestedScrollView>
+
+    <ProgressBar
+        android:id="@+id/spinner"
+        style="?android:attr/progressBarStyle"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:indeterminate="true"
+        app:layout_anchor="@+id/nestedScrollView"
+        app:layout_anchorGravity="center" />
+
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

add_to_app/books/android_books/app/src/main/res/layout/book_card.xml

@@ -0,0 +1,69 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    >
+
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="21dp"
+        android:layout_marginStart="21dp"
+        android:layout_marginEnd="21dp"
+        android:layout_marginBottom="2dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp">
+
+            <TextView
+                android:id="@+id/title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:textAppearance="?attr/textAppearanceHeadline5"
+                tools:text="Title" />
+
+            <TextView
+                android:id="@+id/subtitle"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:textAppearance="?attr/textAppearanceSubtitle1"
+                android:textColor="?android:attr/textColorSecondary"
+                tools:text="subtitle" />
+
+            <TextView
+                android:id="@+id/author"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="16dp"
+                android:textAppearance="?attr/textAppearanceBody1"
+                android:textColor="?android:attr/textColorSecondary"
+                tools:text="Author" />
+
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_margin="8dp"
+                android:orientation="horizontal"
+                android:layout_gravity="end">
+                <com.google.android.material.button.MaterialButton
+                    android:id="@+id/edit"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="@string/edit"
+                    style="?attr/borderlessButtonStyle"
+                    />
+            </LinearLayout>
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+</FrameLayout>
+

add_to_app/books/android_books/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

add_to_app/books/android_books/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

add_to_app/books/android_books/app/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="colorPrimary">#6200EE</color>
+    <color name="colorPrimaryDark">#3700B3</color>
+    <color name="colorAccent">#03DAC5</color>
+</resources>

add_to_app/books/android_books/app/src/main/res/values/strings.xml

@@ -0,0 +1,5 @@
+<resources>
+    <string name="app_name">Books</string>
+    <string name="edit">Edit</string>
+    <string name="author_prefix">By: %1$s</string>
+</resources>

add_to_app/books/android_books/app/src/main/res/values/styles.xml

@@ -0,0 +1,10 @@
+<resources>
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+</resources>

add_to_app/books/android_books/build.gradle

@@ -0,0 +1,26 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+buildscript {
+    ext.kotlin_version = "1.6.0"
+    repositories {
+        google()
+        mavenCentral()
+    }
+    dependencies {
+        classpath "com.android.tools.build:gradle:7.4.2"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

add_to_app/books/android_books/gradle.properties

@@ -0,0 +1,21 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx2048m
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app"s APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Automatically convert third-party libraries to use AndroidX
+android.enableJetifier=true
+# Kotlin code style for this project: "official" or "obsolete":
+kotlin.code.style=official

add_to_app/books/android_books/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

add_to_app/books/android_books/gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# 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.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

add_to_app/books/android_books/gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

add_to_app/books/android_books/settings.gradle

@@ -0,0 +1,7 @@
+include ':app'
+setBinding(new Binding([gradle: this]))
+evaluate(new File(
+  settingsDir,
+  '../flutter_module_books/.android/include_flutter.groovy'
+))
+rootProject.name = "android_books"