--- title: "Code Push for Android add-to-app" description: "Use Code Push in an add-to-app scenario with an Android app" --- This guide explains how to use Shorebird in an Android add-to-app scenario (that is, your app embeds Flutter UI in non-Flutter UI). If you are new to this pattern, see the [Add Flutter to an existing app](/flutter-concepts/add-to-app/) Flutter Concepts article first. Note If your app is a pure Flutter app, follow the [standard Code Push guide](/code-push/initialize) instead. ## Prerequisites [Section titled “Prerequisites”](#prerequisites) This guide assumes you have already have an Android app and a Flutter module. The Android app will be named `android_app` and the Flutter module will be named `flutter_module`. This guide also assumes that you have created a Shorebird account. If you have not, see the [Code Push guide](/code-push/initialize) for instructions. The reference code for this guide is available at . ## Add Shorebird to your Flutter module [Section titled “Add Shorebird to your Flutter module”](#add-shorebird-to-your-flutter-module) First, run `shorebird init` in your Flutter module: ``` shorebird init ``` ## Create a Shorebird release [Section titled “Create a Shorebird release”](#create-a-shorebird-release) Create a Shorebird release for your Flutter module: ``` shorebird release aar --release-version 1.2.3+1 ``` The `release-version` parameter needs to match the version of the Android app that uses this module (i.e., `versionName+versionCode` from the app’s `app/build.gradle` file). Note Because Shorebird only works with release builds, this will only produce a release version of your archive. This is similar to running `flutter build aar --no-debug --no-profile`. Note This command creates an `aar` with a build number of `1.0`. As with the `flutter build aar` command, you may optionally provide a different build number using the `--build-number` argument, although this is not necessary. The build number is used to identify the Flutter module in your app’s `build.gradle` file, as you can see [below](#update-your-android-app-to-use-this-version-of-the-flutter-module). Shorebird does not use the build number, but **it should remain consistent between a release and patches to that release**. ## Update your Android app to use the `download.shorebird.dev` Maven repository [Section titled “Update your Android app to use the download.shorebird.dev Maven repository”](#update-your-android-app-to-use-the-downloadshorebirddev-maven-repository) In `settings.gradle`: ``` dependencyResolutionManagement { repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS) repositories { google() mavenCentral() + maven { + // This is a relative path from this settings.gradle file to the + // my_flutter_module/build/host/outputs/repo directory. + url '../my_flutter_module/release' + } + maven { - url 'https://storage.googleapis.com/download.flutter.io' + url 'https://download.shorebird.dev/download.flutter.io' + } } } ``` Note Even though is replaced with , any Flutter dependencies that are not unique to Shorebird will still be downloaded from . This will only work for versions of Flutter that Shorebird supports. ## Update your Android app to use this version of the Flutter module [Section titled “Update your Android app to use this version of the Flutter module”](#update-your-android-app-to-use-this-version-of-the-flutter-module) In `app/build.gradle`, add the following: ``` buildTypes { release { // ... + // The Dart compiler builds libapp.so directly (does not use clang),and already strips + // symbols. However when llvm-strip is run on libapp.so, the symbols are re-sorted + // causing the hash of the library to change (which can confuse Shorebird tools). + // This line tells gradle to skip the unnecessary llvm-strip step for libapp.so + // thus ensuring that the libapp.so that Shorebird sees is byte-identical to the one + // which ends up in the APK/AAR/AAB. + packaging.jniLibs.keepDebugSymbols.add("**/libapp.so") // ... } } dependencies { // ... + releaseImplementation 'com.example.my_flutter_module:flutter_release:1.0' // ... } ``` ## Verify that your app runs [Section titled “Verify that your app runs”](#verify-that-your-app-runs) In Android Studio, update the active build variant to release and run your app. Your app should work as before with no differences. To set the active build variant to release, click on the “Build Variants” tab in the lower left corner of Android Studio. Then select “release” from the “Active Build Variant” dropdown. ![Android Studio build variant set to release](/_astro/hybrid_android_screenshot.BaEBo9fG_ZItjf.webp) Attempting to build with a non-release build variant will not be able to resolve Flutter symbols in your app. ## Submit your app to the Play Store [Section titled “Submit your app to the Play Store”](#submit-your-app-to-the-play-store) This step isn’t covered in detail here, but this is where you would submit your app to the Play Store. For Code Push to work, it is important that you submit *with the same `aar` generated by the release command above*. ## Verify that Shorebird is working with a patch [Section titled “Verify that Shorebird is working with a patch”](#verify-that-shorebird-is-working-with-a-patch) Make an edit to the code in your Flutter module. Then run: ``` shorebird patch aar --release-version 1.2.3+1 ``` Note If you provided a build number to the `shorebird release aar` command using the `--build-number` argument, you must also provide that same build number to the `shorebird patch aar` command. As with the `release` command, the release version should be the version of the Android app that uses this module. Now relaunch the app, navigate to the Flutter screen, and verify that the patch is recognized and applied. In logcat, you should see output like the following: ``` [INFO:shorebird.cc(109)] Shorebird updater: no active patch. [INFO:shorebird.cc(113)] Starting Shorebird update updater::network: Sending patch check request: PatchCheckRequest { app_id: "baad0583-6810-44a7-9034-6aadb8127f29", channel: "stable", release_version: "1.0.0+8", patch_number: None, platform: "android", arch: "aarch64" } updater::updater: Patch 1 successfully installed. updater::updater: Update thread finished with status: Update installed ```