Omolara Adejuwon, Brainspace VG @_larikraun Lagos Diving into Android App Bundle 

What is Android App Bundle? Lagos 

The Android App Bundle (.aab) is a new upload/publishing format. It mirrors the .apk format with a little bit of ‘stew’ ;) 

What is the need? ● It makes the support of different configurations better - Dynamic delivery ● Your users have a smaller APK to download ● It favors modularization i.e cleaner code base ● Leads us to dynamic features ● Google Play console handles the serving for you Lagos 

Image source What’s inside App Bundle? 

Dynamic Delivery Lagos 

Dynamic delivery serves only those files to the users which they need and this is what allows us to make apps smaller 

● A fundamental component of Dynamic Delivery. ● Available on L+. ● With split APKs Google Play can break up a large app into smaller packages that are installed on a user's device based on device’s configuration Split APKs 

● Base APK: contains all common code and resources ● Configuration APKs: contains resources based on device’s config i.e locale, architecture, screen density ● Dynamic Feature APKs: contains codes that can be downloaded at a later time. This will be discussed later in the presentation. 3 Kinds of Split APKs 

Image source Screen density Architecture Locale Base APK Configuration APKs 

Device Configuration = en + xxhdpi + arm64 BASE ARM64 XXHDPI EN 

12 android{ ... bundle { language { /* This property is set to true by default. Specifies that the app bundle should not support configuration APKs for language resources. These resources are instead packaged with each base and dynamic feature APK.*/ enableSplit = false } density { enableSplit = true } abi { enableSplit = true } } } Version 3.2+ + /app/build.gradle 

● Using Bundletool ● Google Play console - Internal test track Testing App Bundles * App Bundles are not installable until they are signed 

14 java -jar bundletool build-apks --bundle=PATH_TO_APP_BUNDLE \ --output=PATH_TO_OUTPUT_APKS --ks=PATH_TO_KEYSTORE \ --ks-pass=pass:KEYSTORE_PASSWORD --ks-key-alias=KEY_ALIAS \ --key-pass=pass:KEY_PASSWORD --overwrite Bundletool -> Generate APKs http://github.com/google/bundletool https://developer.android.com/studio/command-line/bundletool 

15 java -jar bundletool install-apks --apks=PATH_TO_OUTPUT_APKS Bundletool -> Install on connected device http://github.com/google/bundletool https://developer.android.com/studio/command-line/bundletool 

Enroll in Google Play App Signing Create and manage your releases - upload app bundle Google Play serves APKs to devices as required Publishing App Bundles 

Dynamic Features Lagos 

It allows you break your app into modules/features. Your app handles the download and installation of each module when the user needs it. The core of this mechanism is the Play core library. This further helps your initial app size really small 

● How many % of your users really need that feature? ● How large is the feature? ● Can your users wait a few seconds to download that feature? When to use dynamic features 

20 Image source 

Getting started with Dynamic Feature Lagos 

22 

23 

app/build.gradle dynamicFeatures = [":module_one",":module_two"] Generated content 

module/build.gradle apply plugin: 'com.android.dynamic-feature' dependencies { ... implementation project(':app') } Generated content 

26 module/src/AndroidManifest.xml : you can provide your feature module’s title and other configurations Generated content 

27 module/src/AndroidManifest.xml dist:onDemand=”true/false”: indication that this module is only available to the user when the user requests from the application Generated content 

28 module/src/AndroidManifest.xml : indication that this module should be available to Pre L devices at first installation Generated content 

Installing Dynamic Feature in app Lagos 

app/build.gradle api 'com.google.android.play:core:1.3.5' Play core library makes it possible to install and manage modules 

31 //create splitInstallManager val manager = SplitInstallManagerFactory.create(this) 

32 val manager = SplitInstallManagerFactory.create(this) //check if module has already been installed if (manager.installedModules.contains(module_name)) { //load the module } 

33 val manager = SplitInstallManagerFactory.create(this) if (manager.installedModules.contains(module_name)) { //load the module } // Create request to install a feature module by name. val request = SplitInstallRequest.newBuilder() .addModule(module_name) .build() 

34 val manager = SplitInstallManagerFactory.create(this) if (manager.installedModules.contains(module_name)) { //load the module } // Create request to install a feature module by name. val request = SplitInstallRequest.newBuilder() .addModule(module_name) .build() // Load and install the requested feature module. manager.startInstall(request) .addOnSuccessListener {} .addOnFailureListener {} 

35 val listener = SplitInstallStateUpdatedListener { state -> state.moduleNames().forEach { name -> // Handle changes in state. when (state.status()) { SplitInstallSessionStatus.DOWNLOADING -> {} SplitInstallSessionStatus.REQUIRES_USER_CONFIRMATION -> { /*This may occur when attempting to download a large module like 10MB */ startIntentSender(state.resolutionIntent()?.intentSender, null, 0, 0, 0) } SplitInstallSessionStatus.INSTALLED -> {} SplitInstallSessionStatus.INSTALLING -> {} SplitInstallSessionStatus.FAILED -> {} } } } 

36 //register the listener manager.registerListener(listener) //unregister the listener manager.unregisterListener(listener) 

37 //defer installation of some modules manager.deferredInstall(modules).addOnSuccessListener {} //uninstall modules that are no more needed val installedModules = manager.installedModules.toList() manager.deferredUninstall(installedModules).addOnSuccessListener {} 

38 ● https://developer.android.com/studio/projects/dynamic-delivery ● https://developer.android.com/studio/command-line/bundletool ● https://events.google.com/io/schedule/?section=may-8&sid=b9ea bde0-be05-492c-bf9e-c3f772f1db7e ● https://codelabs.developers.google.com/codelabs/your-first-dyn amic-app/index.html Useful Resources 

Lagos Thank you! Omolara Adejuwon, Brainspace VG @_larikraun