Android Developers Blog: January 2022

Improving App Performance with Baseline Profiles

28 January 2022

Or how to improve startup time by up to 40%

Posted by Kateryna Semenova, DevRel Engineer; Rahul Ravikumar, Software Engineer; Chris Craik, Software Engineer

Why is startup time important? A lot of apps find correlation between app performance and user engagement. People expect apps to be responsive and fast to load. Startup time is one of the major metrics for app performance and quality. Some of our partners have already invested a lot of time and resources for app startup optimizations. For example, check out the Facebook story. In this blog post we’ll discuss Baseline Profiles and how they improve app and library performance, including startup time by up to 40%. While this blogpost focuses on startup, baseline profiles also significantly improve jank as well. History Android 9 (API level 28) introduced ART optimizing profiles in Play Cloud to improve app startup time. On average, we’ve seen that apps' cold starts are at least 15% faster across a variety of devices when Cloud Profiles are available. How do Profiles work? When the app is first launched after install or update, its code runs in an interpreted mode until it is JITted. In an APK, Java and Kotlin code is compiled as dex bytecode, but not fully compiled to machine code (since Android 6), due to the cost of storing and loading fully compiled apps. Classes and methods that are frequently used in the app, as well as those used for app startup, are recorded into a profile file. Once the device enters idle mode, ART compiles the apps based on these profiles. This speeds up subsequent app launches. Starting with Android 9 (API level 28), Google Play also provides Cloud Profiles. When an app runs on a device, the profiles generated by ART are uploaded by the Play Store app and aggregated in the cloud. Once there are enough profiles uploaded for an application, the Play app uses the aggregated profile for subsequent installs. Problem While Cloud Profiles are great when they are available, they aren't always ready to be used when an app is installed. Collecting and aggregating the profiles usually takes several days, which is a problem when many apps update on a weekly basis. Many users will install an update before the Cloud Profile is available. The Google Android team started looking for other ways to improve the latency of profiles. Solution Baseline Profiles are a new mechanism to provide profiles which can be used on Android 7 (API level 24) and higher. A baseline profile is an ART profile generated by the Android Gradle plugin using a human readable profile format that can be provided by apps and libraries. An example might look like this: HSPLandroidx/compose/runtime/ComposerImpl;->updateValue(Ljava/lang/Object;)V HSPLandroidx/compose/runtime/ComposerImpl;->updatedNodeCount(I)I HLandroidx/compose/runtime/ComposerImpl;->validateNodeExpected()V PLandroidx/compose/runtime/CompositionImpl;->applyChanges()V HLandroidx/compose/runtime/ComposerKt;->findLocation(Ljava/util/List;I)I

Example for Compose library.

The binary profile is stored in a specific location in the APK assets directory (assets/dexopt/baseline.prof). Baseline Profiles are created during build time, shipped as part of the APK to Play, and then sent from Play to users when an app is downloaded. They fill the gap in the ART Cloud Profile pipeline, when Cloud Profiles are not yet available, and automatically merge with Cloud Profiles when they are.

This diagram displays the baseline profile workflow from creation through end-user delivery.

One of the biggest benefits of Baseline Profiles is that they can be developed and evaluated locally so developers can see realistic end-user performance improvements. They are also supported on a lower version of Android(7 and higher) than Cloud Profiles, which are only available starting in Android 9. Impact App devs In early 2021, Google Maps switched from a two-week to a one-week release cycle. More frequent updates meant more frequently discarding local pre-compilation, and more users experiencing slow launches without Play Cloud Profiles. By using Baseline Profiles, Google Maps improved their average startup time by 30% and saw a corresponding increase in searches by 2.4%, an immense gain for such an established app. Library devs Code in a library is just like that of an app - it's not fully compiled by default, which can be a problem if it does significant work on the critical path of startup. Jetpack Compose is a UI library that is not a part of the Android system image and thus not fully compiled when installed, unlike much of the Android View toolkit code. This was causing performance problems, especially for the first few cold launches of the app. To solve this problem, Compose uses profile installer. It ships baseline profile rules which reduce startup time and jank in Compose apps. Google PlayStore’s search results page has been re-written with Compose. After incorporating the Baseline Profile rules from Compose, time to render the initial search results page with images improved by ~40%. The Android team has also added Baseline Profiles to relevant AndroidX libraries. This benefits all Android apps using these libraries. Constraint Layout has found shipping profile rules reduces animation frame times by more than one millisecond. How to use Baseline Profiles
Create a custom Baseline Profile All apps and library developers can benefit from including Baseline Profiles. Ideally, developers create profiles for their most critical user journeys to ensure that those journeys have consistently fast performance regardless of whether cloud profiles are available. Check out the detailed guide on how to set up Baseline Profiles for both app and library developers.
Update dependencies If you are not ready to generate Baseline Profiles for your app right now, you can still benefit from them by updating your dependencies. If you build with Android Gradle Plugin 7.1.0-alpha05 or newer, you'll get Baseline Profiles included in your APK that are already provided by libraries (such as Jetpack). Google Play compiles your app with these profiles at install time. You can supplement these profiles as part of building your application.
Measure Improvements Don’t forget to measure improvements. Follow the steps on how to measure startup with the generated profile locally. Provide feedback Please share your feedback and let us know your experience!

Building apps for Android Automotive OS

27 January 2022

Posted by Madan Ankapura, Product Manager Today we’re announcing the availability of version 1.2 beta of the Car App Library, enabling app developers to start building their navigation, parking, and charging apps for Android Automotive OS. Now, developers can begin building and testing apps for these categories using the Automotive OS emulator across both Android Automotive OS and Android Auto. For the entire list of changes in v1.2 beta, please see the release notes. To start building your app for the car, check out our updated developer documentation, car quality guidelines, and design guidelines. As announced earlier, drivers of Polestar 2 and Volvo cars can now download charging (ChargePoint, PlugShare), parking (Spothero, Parkwhiz), and navigation (Flitsmeister, Sygic) apps developed with the Car App Library by joining the Google Group and opting-in to each app's beta on the Google Play store, with your Gmail account.

Car App Library apps on Android Automotive OS are automatically rendered to be consistent with the rest of the experience within each car, without additional work needed from developers.. For example,

Polestar 2

Volvo

Polestar 2 setting with labeled On / Off switches for PlugShare

Volvo settings with sliding switches for PlugShare

Polestar 2 sign-in screen for SpotHero

Volvo sign-in screen for SpotHero

Example of app customization on Android Automotive OS

Experience for yourself how your app will look within the different systems, by accessing the OEM emulator system images downloadable in Android Studio. You can begin developing your charging, parking and navigation apps for Android Automotive OS today, and we are working to enable you to publish your apps to the Google Play store in the coming months (stay tuned!). Beyond navigation, rideshare drivers spend a lot of time in their vehicles and will benefit from safer interactions if those apps can be brought to the car’s screen. We are working with Lyft and Kakao Mobility to bring their driver app experiences into the car in the coming months.

We are also pleased to announce that we are expanding support to all Points of Interest apps. Beyond charging and parking, this allows any app that will help users discover and search for interesting locations on a map, and optionally enable them to navigate to such points. We are partnering with MochiMochi, Fuelio, Prezzi Benzina, and NAVITIME JAPAN as our early access partners. If you’re interested in joining our Early Access Program in the future, please fill out this interest form. You can get started with the Android for Cars App Library today, by visiting g.co/androidforcars.

Announcing Glance: Tiles for Wear OS made simple

26 January 2022

Posted by Anna Bernbaum, Associate Product Manager
Last year we announced the Wear Tiles API. To complement that Java API, we are excited to announce that support for Wear OS Tiles has been added to Glance, a new framework built on top of Jetpack Compose designed to make it easier to build for surfaces outside your app on Android. We'd love to get your feedback on this alpha version. Tiles provide Wear OS users easy access to the information and actions they need in order to get things done quickly. They also are one of the most used surfaces on Wear OS. Just one swipe away from the Watch Face, users can quickly access the most important information or actions from an app, like start a timer or get the latest weather forecast.

Let's see how we can create a Tile with Glance: class HelloTileService : GlanceTileService() { @Composable override fun Content() { Text(text = "Hello Glance") } } The simple code above generates the Tile below.

“Hello Glance” Tile sample with Glance

Note: Using Glance-wear-tiles requires`minSdkVersion`>= 26.How it works Glance creates “glanceable” experiences across Android surfaces using a base-set of Composables. For Tiles on Wear OS, Glance translates Composables into Tiles.

Diagram: Glance structure

Glance requires Compose to be enabled and depends on Runtime, Graphics, and Unit UI Compose layers, but it’s not directly interoperable with other existing Jetpack Compose UI elements, like Compose for Wear OS. What’s in the Alpha This initial release introduces the main APIs to build wear Tiles:

GlanceTileService - A service to create your tile in the composable Content() function.

Initial set of Glance Composables: Box, Row, Column, Text, Image, Spacer, CurvedRow, CurvedText.

GlanceModifier - Plays the same role as androidx.compose.ui.Modifier but for the Glance composables.

actionStartActivity - Starts an Activity from a user interaction.

TimelineMode.SingleEntry and TimelineMode.TimeBoundEntries - Handle single-entry and time bound timeline entries.

GlanceStateDefinition - Persistent tile state

LocalTimeInterval - Local compositions (similar to LocalState)

We are working on bringing even more functionality with default theming, further Android Studio support, and more. Stay tuned for new releases. Get started with Glance For a quick start, take a look at the samples in the AndroidX repository. Glance works with the latest stable Android Studio, although since Glance relies on Compose Runtime, follow the steps on the Jetpack Compose docs to set it up first. The Alpha version is your opportunity to influence the APIs, so please share your feedback and let us know your experience! Happy Composing with Glance!

Android Studio Bumblebee (2021.1.1) Stable

25 January 2022

Posted by Adarsh Fernando, Product Manager, Android

The Android Studio team has been abuzz with the stable release of Android Studio Bumblebee (2021.1.1) 🐝 and Android Gradle plugin (AGP) 7.1.0; the latest versions of Android official IDE and build system. We’ve improved functionality across a broad area of the typical developer workflow: Build and Deploy, Profiling and Inspection, and Design. Some notable additions include a unified test execution between Android Studio and your continuous integration (CI) server ✅, convenient pairing flows to support ADB over Wi-Fi 📲, Improved Profiler tools to help you identify and analyze jank in your app 🕵️, and new ways to preview animations 🎥 and UI interactions without deploying your app to a device. As always, this release wouldn’t be possible without the early feedback from our Preview users. So read on or watch below for further highlights and new features you can find in this stable version. If you’re ready to jump in and see for yourself, head over to the official website to download Android Studio Bumblebee (2021.1.1).What’s in Android Studio Bumblebee (2021.1.1) Below is a full list of new features in Android Studio Bumblebee (2021.1.1), organized by the three major themes. Build and Deploy

New Device Manager: This new tool window in Bumblebee makes it easier to see and manage your virtual and physical test devices, and you can open it by selecting View > Tool Windows > Device Manager from the main menu bar. In the Virtual tab, create a new device, review device details, delete a device, or anything else you used to do from the now removed AVD Manager. In the Physical tab, quickly pair to a new device using ADB Wi-Fi and see details of each physical device at a glance, or quickly inspect each device’s file system using the Device File Explorer with a click of a button. Learn more about the New Device Manager in the release notes.

Device Manager

ADB over Wi-Fi: Bumblebee includes a simplified flow to connect to your Android 11 and higher devices over Wi-Fi for deployment and debugging using ADB. After you enable debugging over Wi-Fi on your device, select the Pair using Wi-Fi action in the Physical tab of the new Device Manager to open the pairing wizard. Then follow the steps provided to pair to a device connected over the same network. Learn more.

Pairing a device with ADB over Wifi

Run Instrumented Tests in Android Studio using Gradle: Have you ever run tests in Android Studio with different results than the same tests running on your CI? This can be a frustrating issue that leads to lost productivity. To resolve this issue, we’ve introduced a new test runner to Android Gradle plugin (AGP) 7.1.0 that Android Studio Bumblebee uses by default when running instrumentation tests, so all your tests run through a unified test runner. This is a similar improvement to Android Studio Arctic Fox, where we started running all unit tests via Gradle by default. And, similarly, this improvement doesn’t require you to change how you write or run your tests!

Using different runners lead to inconsistent results

Android Studio now runs instrumentation tests via Gradle

Android Gradle Plugin Upgrade Assistant now updates API usage: Originally introduced in Android Studio 4.2, the AGP Upgrade Assistant helped users update their projects to the latest version, and improvements in Arctic Fox provided a new UI with the ability to review and select the upgrade version and steps. In Bumblebee, the Upgrade Assistant now also checks for and offers to update your DSL to help you avoid using deprecated APIs before they are deleted. For more information see the Android Gradle Plugin DSL/API migration timeline.

Non-Transitive R classes on for new projects: Android Studio Arctic Fox introduced new refactoring tools to help you use non-transitive R classes to enable faster builds for applications with multiple modules. When creating new projects using Bumblebee, the IDE configures your project to use non-transitive R classes, by default. While this does bring performance improvements, you now have to refer to R classes by their proper package name, and not by the package names of their parent modules, as they will no longer resolve transitively. For more information see Use non-transitive R classes.

Emulator tool window enabled by default: Introduced in Android Studio 4.1, the Emulator launches within an Android Studio tool window and allows you to deploy and interact with virtual Android devices while fully remaining within the context of the IDE. The changes ads an improved UX for extended controls and snapshot management. For more information see Run the Android Emulator directly in Android Studio.

Apple Silicon Support Update - For those using macOS on Apple Silicon (arm64) hardware, Android Studio Arctic Fox and the Android Emulator have supported this new architecture since last year. However, with this release, we have now updated the Android SDK platform tools v32.0.0 (which includes ADB and fastboot) and build tools v32.1.0 (which includes aapt) to be universal binaries so that your Android developer tools no longer need the Rosetta binary translator to run. Based on community feedback, those developers on this hardware platform have seen notable performance improvements. See release notes.

Profile and Inspect

Jank detection track in Profilers: When profiling your app using devices running Android 11 (API level 30) or higher, the CPU profiler now shows a new group of tracks that illustrate the stages of each frame under Frame Lifecycle: Application, Wait for GPU, Composition and Frames on display. Each track labels the frames with a frame number and color-codes the rectangle to make it easy for you to visualize where a particular frame is in its lifecycle, along with guides you can toggle to compare with Vsync events. You can use this data to understand where Jank might occur in your app and investigate the root causes. In the Analysis panel, there is now a Frames tab, which conveniently summarizes rendering information for all frames. For more information, see UI jank detection.

Detailed frame lifecycle information in the CPU Profiler

Profileable app profiling support in Studio Profilers: When profiling your app, it’s important to generate accurate data with the version of your app that most closely resembles what your users will install. To do so, you can now include the <profileable> property in your app’s manifest to profile apps that are not debuggable, as shown below.

<profileable android:shell="true"/>

Profileable is a manifest configuration introduced in Android 10, and is available for CPU and Memory profiling tasks. Using the profileable flag instead of the debuggable flag has the key advantage of lower overhead for performance measurement; however, certain profiling features are not available for Profileable builds, such as the Event timeline, API initiated CPU profiling, heap dumps, or live location recordings. For more information, see Profileable applications.

Inspect Jobs, Alarms, and Wakelocks: The Background Task Inspector has been expanded to allow you to inspect Jobs, Alarms, and Wakelocks. You can see live information on how these background tasks are being scheduled, and see detailed information about their execution, similar to how you can inspect Workers. Additionally, when inspecting Workers, you can track and inspect Jobs that your Workers schedule for you. If you used to use the Energy Profiler in previous versions of the IDE, you should now navigate to View > Tool Windows > App Inspection from the menu bar and select the Background Task Inspector to inspect Jobs, Alarms, and Wakelocks.

Inspect Jobs, Alarms, and Wakelocks in the Background Task Inspector

Network Inspection: The Network Profiler has now migrated to the App Inspection tool window, to allow for a lighter-weight experience for inspecting network traffic in your app. The look and feel of the Network Profiler has been maintained and works with any debuggable app on devices running API level 26 and higher. To use the new inspector, select View > Tool Windows > App Inspection from the menu bar and select the Network Inspector. For more information, see Inspect network traffic with the Network Inspector.

Capture Layout Inspector snapshots: You can now capture snapshots of your app’s layout hierarchy to save, share, or inspect later. Snapshots capture the data you would typically see when using the Layout Inspector, including a detailed 3D rendering of your layout, the component tree of your View, Compose, or hybrid layout, and detailed attributes for each component of your UI. When inspecting the layout of a live running app, click Export snapshot from the Layout Inspector toolbar and save the snapshot with an *.li extension. You can then load a Layout Inspector snapshot by selecting File > Open from the main menu bar, and opening a *.li file. The snapshot appears in a tab in the Editor window, so that you can easily compare it with your running app. Learn more at Capture layout hierarchy snapshots.

Support for Compose semantics in the Layout Inspector: In Compose, Semantics describe your UI in an alternative manner that is understandable for Accessibility services and for the Testing framework. In Android Studio Bumblebee, you can now use the Layout Inspector to inspect semantic information in your Compose layouts. When selecting a Compose node, use the Attributes window to check whether it declares semantic information directly, merges semantics from its children, or both. To quickly identify which nodes include semantics, either declared or merged, use select the View options dropdown in the Component Tree window and select Highlight Semantics Layers.

Design

Interactive Preview: Android Studio Arctic Fox launched with support to statically preview your composable functions in the Design / Split window of the Editor. In Bumblebee, we’ve expanded functionality to allow you to interact with certain components of your Compose layouts, to validate behavior without building and deploying the full app to a running device! To get started, navigate to a previewable compose function and click Start Interactive Mode in the Design / Split window. For more information see Interactive mode.

Interact with the Compose Preview to validate behavior

Animated Vector Drawables Preview: The Preview window is now also available when viewing vector drawables. When viewing a static drawable, you can use the preview window to change background options between “None”, “White”, “Black”, “Checkedered”, to view your drawable against different conditions. Animated drawables also provide the option to preview the animation at different speeds as well as backgrounds, to help you test animations before using them in your app. To learn more, see Animated Vector Drawables (AVD) preview.

Preview your animated vector drawables

Updated Device picker for design tools: To simplify designing your app for the diverse number of Android devices, we’ve updated the device picker in various design tool windows, such as Layout Editor and Layout Validation, with reference devices that reflect popular sizes of each device form factor. From phones to tablets, and Wear devices to Android TVs, it’s now easier to preview, validate, or edit your layout on screen sizes that are most representative of popular real-world devices. To learn more, see Change the preview appearance.

To recap, Android Studio Bumblebee (2021.1.1) includes these new enhancements & features: Build and Deploy

Run Instrumented Tests in Android Studio using Gradle

Android Gradle Plugin Upgrade Assistant now updates API usage

Non-Transitive R classes on for new projects

New Device Manager

ADB over Wi-Fi

Emulator tool window enabled by default

Apple Silicon Support Update

Profile and Inspect

Jank detection track in Profilers

Profileable app profiling support in Studio Profilers

Inspect Jobs, Alarms, and Wakelocks in the Background task Inspector

Capture Layout Inspector snapshots

Support for Compose semantics in the Layout Inspector

Design

Interactive Preview

Animated Vector Drawables Preview

Updated Device picker for design tools

Google Play Games beta launches on PC in Korea, Taiwan, and Hong Kong

20 January 2022

Posted by Arjun Dayal, Group Product Manager, Google Play Games

In December, we announced that Google Play Games will be coming to PCs. As part of our broader goal to make our products and services work better together, this product strives to meet players where they are and give them access to their games on as many devices as possible. We're excited to announce that we’ve opened sign-ups for Google Play Games as a beta in Korea, Taiwan, and Hong Kong.

Introduction video of Google Play Games beta

Users participating in the beta can play a catalog of Google Play games on their Windows PC via a standalone application built by Google. We’re excited to announce that some of the most popular mobile games in the world will be available at launch, including Mobile Legends: Bang Bang, Summoners War, State of Survival: The Joker Collaboration, and Three Kingdoms Tactics, which delight hundreds of millions of players globally each month.

This product brings the best of Google Play to more laptops and desktops, enabling immersive and seamless gameplay sessions between a phone, tablet, Chromebook, and Windows PC. Players can easily browse, download, and play their favorite mobile games on their PCs, while taking advantage of larger screens with mouse and keyboard inputs. No more losing your progress or achievements when switching between devices, it just works with your Google Play Games profile! Play Points can also be earned for Google Play Games activity on PCs.

Google Play Games gameplay on multiple devices including a phone, PC, and tablet.

We’re thrilled to expand our platform for players to enjoy their favorite Android games even more. To sign up for future announcements, or to access the beta in Korea, Taiwan, and Hong Kong, please go to g.co/googleplaygames. If you’re an Android developer looking to learn more about Google Play Games, please express interest on our developer site. We’ll have more to share on future beta releases and regional availability soon. Windows is a trademark of the Microsoft group of companies.
Game titles may vary by region.

Android Basics and Training Update

20 January 2022

Posted by Dan Galpin, Developer Relations Engineer

In October of 2021 we released the final unit of Android Basics in Kotlin, our free, self-paced programming course that makes Android development accessible to everyone. It teaches people with no programming experience how to build Android apps. Along the way, students learn the fundamentals of programming and the basics of the Kotlin programming language. In response to feedback from educators and learners, we've continued to iterate on our course material, adding projects that allow you to apply learnings along with new topics that can prepare students for more advanced material. A focus on basics With these updates, Android Basics in Kotlin now covers the key material covered in Android Kotlin Fundamentals, so we will be sunsetting the latter course. More advanced learners are encouraged to work through the Basics material, skipping sections that they are familiar with and moving straight to quizzes. Focusing on basics means that intermediate and advanced learners that might be missing a key concept will have what they need to succeed with this material. This also allows our team to focus on making sure our courseware continues to represent our most recent guidance. In addition to courseware, we're continuing to provide codelabs, code samples, documentation, and video content to serve learners at all levels. What's next? Our team is hard at work on the next course that will teach people how to program Android applications using Jetpack Compose. We're looking forward to teaching Android’s modern toolkit for building native UI because of all the ways that it simplifies and accelerates Android UI development. What to do now Taking the current course will teach you the fundamentals of app development, serving as a great starting point should you want to explore the existing Jetpack Compose Learning Pathway, or jump into the upcoming Android Basics with Compose course. You'll have a foundation that you can build on as you continue to explore the world of Android development. Both versions of Android Basics are planned to coexist, giving the option of learning Android with either UI toolkit. Whether you’ve never built an app before but want to learn how, or just want to brush up on some of our latest best practices, check out the Android Basics in Kotlin course.