Android Developers Blog

Celebrating 5 years of Kotlin on Android

17 August 2022

Posted by Márton Braun, Developer Relations Engineer

Five years ago, at the 2017 Google I/O Keynote, we did something we had never done before: we announced official support for a new programming language to build Android apps with: Kotlin. It was great to see how excited the Android developer community was about this announcement.Kotlin Foundation As highlighted in those initial I/O announcements, Kotlin is interoperable, mature, production-ready, and open source. It also has outstanding IDE support, as JetBrains develops both the language and its tooling.

Now, five years have passed since the original announcement. To celebrate the amazing language that now powers modern Android app development, we’re taking a quick look at the journey of Kotlin on Android. This post includes quotes from a handful of people who were involved in making Kotlin on Android a success, who are joining us for this celebration.Early years

“The decision by Google to add support for Kotlin, I think we underestimate how wild of a notion that was at the time. The odds of another company that size making a similar decision based on community support and enthusiasm is very low.“ (Christina Lee, Android engineer at Pinterest, Kotlin and Android GDE)
launchedAndroid KTX librariesR8ARTreference documentation

Going Kotlin-first

At Google I/O 2019, we committed to Kotlin-first Android development, further increasing our investments in the language.

“If you look at a Kotlin new users graph, you immediately notice the two most significant spikes – one in May 2017 and another in May 2019. We have an inside joke about it: ‘Marketing a programming language is easy. All you have to do is make the largest operating system in the world call it an official language during the annual keynote’” (Egor Tolstoy, Kotlin Product Lead at JetBrains)

Being Kotlin-first means that we now design our documentation, samples, training content, new libraries and tools for the Kotlin language first, while still supporting users of the Java programming language.

”Now when we want to start a Jetpack Library, we are writing it in Kotlin unless we have a very, very, very good reason not to do that. It’s clear that Kotlin is the first-class language.” (Yigit Boyar, early proponent of Kotlin within Google, currently leading the development of a handful of Jetpack libraries)

Some examples of Kotlin-first Jetpack libraries are Paging 3 and DataStore, which are both powered by coroutines and Flows for asynchronous operations.

Jetpack Compose, Android’s modern UI toolkit is our greatest commitment to Kotlin so far, as it’s Kotlin-only. It’s powered by a Kotlin compiler plugin, and it makes extensive use of advanced language features like coroutines, top-level functions, and trailing lambdas.

“Kotlin is here to stay and Compose is our bet for the future. Right now, for developers that are starting to learn Android, we’re already recommending the Android Basics with Compose course.” (Florina Muntenescu, Jetpack Compose developer relations lead)

Kotlin beyond Android

Even though Kotlin is a great fit for Android, it’s a general-purpose language and not solely for use on Android. For teams within Google, Kotlin is now generally available to use for both Android and server-side projects. Thousands of Google engineers are writing Kotlin code, and our internal codebase contains more than 8.5 million lines of Kotlin code to date. This number has been increasing rapidly as well, doubling year over year.

“We’ve been working to bring Kotlin to Google engineers for the last few years by adding Kotlin support to all the tools they use. This includes the build system, static analysis tools, libraries and APIs. We’ve talked a lot about encouraging developers to use Kotlin for Android app development, and we strongly encourage using Kotlin for server-side development as well.” (Kevin Bierhoff, lead of the Kotlin at Google team, which supports Google engineers writing Kotlin code)

gRPC Kotlin and Kotlin for protocol buffers are examples of Kotlin projects Google uses both in Android apps and on servers that have been open sourced and are now receiving community adoption and contributions. Kotlin is also supported on Google Cloud.

Collaboration with JetBrains

There is close collaboration between JetBrains and Google around the development of Kotlin. The Kotlin Foundation was co-founded by the two companies, and it ensures that the language and ecosystem age well.

Google engineers have also been working on improving the compiler and on creating important tooling for the language.

“My team is helping JetBrains with rewriting the Kotlin compiler right now, and we also work on Kotlin Symbol Processing, which is the first compiler-related Kotlin project that’s been completely done at Google. We work more closely with JetBrains than some other parts of Google." (Jeffrey van Gogh, member of the Kotlin Foundation, lead of the Kotlin engineering team at Google)

JetBrains and Google also coordinate new releases of the language and the accompanying tooling so that developers are able to use the latest releases as smoothly as possible.

“The collaboration gets stronger over time, and I’m really excited to see its impact on Kotlin’s future. Our coordinated pre-release checks are getting better and better." (Liliia Abdulina, Kotlin QA team lead at JetBrains)

Learn more and share your own stories

You can read more stories about Kotlin from our interviewees in the accompanying Medium post. We’d also love to hear your stories of learning and adopting Kotlin for Android development! Share them on social media using the hashtag #Hi5KotlinOnAndroid!

Finally, let’s appreciate these kind words about Kotlin’s accomplishments to conclude our story.

“Technology can really change people's lives and it can really make people happier at work. We normally focus on ‘there's null safety’ or ‘there's type inference’ or all these other technical parts. But when you take a step back, there's a whole story in there about all of the people who had their passion for coding ignited or reignited because Kotlin is such a wonderful language. It's just so impressive that the team is able to do what they're able to do and that the community is as good as it is." (Christina Lee, Android engineer at Pinterest, GDE for Android and Kotlin)

Have a nice Kotlin on Android!

*Java is a trademark or registered trademark of Oracle and/or its affiliates.

Android 13 is in AOSP!

15 August 2022

Posted by Seang Chau, VP of Engineering

Today we’re pushing the Android 13 source to the Android Open Source Project (AOSP) and officially releasing the newest version of Android. For developers, Android 13 is focused on our core themes of privacy and security as well as developer productivity, making it easier for you to build great experiences for users. We’ve also continued to make Android an even better OS for tablets and large screens, giving you better tools to take advantage of the 270+ million of these devices in use across the world. You can read more about Android 13 for consumers in our Keyword blog postAndroid 13 is rolling out to Pixel devices starting today. Later this year, Android 13 will also roll out to more of your favorite devices from Samsung Galaxy, Asus, HMD (Nokia phones), iQOO, Motorola, OnePlus, Oppo, Realme, Sharp, Sony, Tecno, vivo, Xiaomi and more.

As always, we thank you for the feedback you’ve shared, and we appreciate the work you’ve done to make your apps compatible with today’s release. Your support and contributions are what make Android a great platform for everyone!

What’s in Android 13 for developers?

Here’s a look at some of what’s new in Android 13 - make sure to check out the Android 13 developer site for details on all of the new features.

Developer productivity and tools

Themed app icons - Android 13 extends Material You dynamic color to all app icons, letting users opt-in to icons that inherit the tint of their wallpaper and other theme preferences. All your app needs to supply is a monochromatic app icon and a tweak to the adaptive icon XML. More here.

Themed app icons adapting to wallpapers colors and dark theme (left).

Per-app language preferences - Android 13 makes it easier to support multilingual users who want to use your apps in a language that’s different from the system language. Android now provides a standard “App language” Settings panel for apps that have opted-in, and you can call a new platform API to get or set the user’s preferred locale at runtime, helping to reduce boilerplate code and improve compatibility. More here.

Per-app languages in Settings

Improved text support - Android 13 includes text and language improvements that help you deliver a more polished experience. Faster hyphenation optimizes hyphenation performance by as much as 200% so you can now enable it in your TextViews with almost no impact on rendering performance. Text conversion APIs make searching and autocompletion faster when using phonetic lettering input for languages like Japanese, Chinese, and others. Android 13 also improves line heights for non-latin scripts (such as Tamil, Burmese, Telugu, and Tibetan), eliminating clipping and making them easier to read. More here.

Improved line height for non-Latin scripts in apps targeting Android 13 (bottom).

Color vector fonts - Android 13 adds rendering support for COLR version 1 (spec, intro video) fonts and updates the system emoji to the COLRv1 format. COLRv1 is a new, highly compact, font format that renders quickly and crisply at any size. For most apps this will just work, and the system handles everything. More here.

COLRv1 vector emoji (left) and bitmap emoji.

Quick Settings Placement API - For apps that provide custom Quick Settings tiles, Android 13 makes it easier for users to discover and add your tiles. Using a new tile placement API, your app can now prompt the user to directly add your custom Quick Settings tile in a single step, without leaving your app. More here.

Programmable shaders - Android 13 introduces programmable RuntimeShader objects, with behavior defined using the Android Graphics Shading Language (AGSL). You can use these shaders to create ripple, blur, stretch, and similar advanced effects in your apps. More here.

Media controls derived from PlaybackState - For apps targeting Android 13, the system now derives media controls from PlaybackState actions, providing a richer set of controls that are consistent across phones and tablet devices and align with other Android platforms such as Android Auto and Android TV. More here.

Android 13 media controls are consistent on phones and tablets.

Bluetooth LE Audio - Low Energy (LE) Audio is the next-generation wireless audio built to enable new use cases like sharing and broadcasting audio to friends and family, or subscribing to public broadcasts for information, entertainment, or accessibility. It’s designed to ensure that users can receive high fidelity audio without sacrificing battery life, and lets them seamlessly switch between different use cases. Android 13 adds built-in support for LE Audio, so developers can use the new capabilities on compatible devices. More here.

MIDI 2.0 - Android 13 adds support for the new MIDI 2.0 standard, including the ability to connect MIDI 2.0 hardware through USB. This updated standard offers features such as increased resolution for controllers, better support for non-Western intonation, and more expressive performance using per-note controllers. More here.

OpenJDK 11 updates - Android 13 Core Libraries now align with the OpenJDK 11 LTS release, with both library updates and Java 11 programming language support for app and platform developers. We plan to bring these Core Library changes to more devices through Google Play system updates, as part of an ART module update for devices running Android 12 and higher. More here.

Predictive back gesture - Android 13 introduces new APIs that let your app tell the system that it will handle back events in advance, a practice we call the "ahead-of-time" model. This new approach is part of a multi-year effort to help you prepare your app to support the predictive back gesture, which is available for testing in this release through a developer option. More here.

Built for tablets

Android 13 extends the 12L update that we released earlier this year, and it delivers an even better experience on tablets. You’ll find features like an enhanced multitasking taskbar, more large-screen layouts and optimizations in system UI and apps, improved compatibility modes for apps, and more. We’re continuing to invest to give you the tools you need to build great experiences for tablets as well as Chromebooks and foldables. You can learn more about how to get started optimizing for large screens, and be sure to check out our large screens developer resources.

Multitasking on tablets with Android 13.

Privacy and security

Photo picker and APIs - A new system photo picker now gives users a standard, privacy-protecting way to share local and cloud-based photos. Photo picker extends Android’s long-standing document picker and makes it easy for users to share specific photos and videos with an app, without giving the app permission to view all media files on the device. Photo picker provides a dedicated experience for photos and videos and includes APIs for apps to access the shared media files. The photo picker experience is now available to users who receive Google Play system updates, on devices (excepting Go devices) running Android 11 and higher. More here.

Photo picker lets users share specific photos and videos with an app.

Notification permission - To help users focus on the notifications that are most important to them, Android 13 introduces a new notifications runtime permission. Apps now need to request the notification permission from the user before posting notifications. For apps targeting Android 12 or lower, the system will handle the upgrade flow on your behalf. More here.

Notification permission dialog in Android 13.

Nearby device permission for Wi-Fi - Android 13 introduces the NEARBY_WIFI_DEVICES runtime permission for apps that manage a device's connections to nearby access points over Wi-Fi. The new permission is required for many commonly-used Wi-Fi APIs and enables apps to discover and connect to nearby devices over Wi-Fi without also needing to acquire the location permission. More here.

Granular permissions for media file access - Photo picker is our recommended solution for user-friendly, permissionless sharing of photos and videos, but for apps that haven’t moved to photo picker yet or for audio use cases, Android 13 adds new granular media permissions. These new permissions replace the READ_EXTERNAL_STORAGE permission and provide access to specific types of media files, including images, video, or audio. We highly recommend moving your app to photo picker if possible; otherwise, use the granular media permissions when targeting Android 13. More here.

Requesting permission to access audio files.

Developer downgradable permissions - Starting in Android 13, apps that no longer require permissions previously granted by the user can use a new API to downgrade the permissions. By removing unused permissions, your app can show that it’s using the minimum permissions needed, which can improve user trust. More here.

Safer exported Intent filters - Android 13 applies stricter rules when delivering explicit intents to exported intent filters in another app that’s targeting Android 13. For intents that specify actions, the system now delivers the intents to the exported component only if the intent matches the receiver’s declared <intent-filter> elements. More here.

Performance for apps

Android 13 improves performance and efficiency for all apps through updates to the ART runtime. We plan to bring these improvements to more Android users through Google Play system updates, as part of our ongoing ART module updates for devices running Android 12 and higher.

Improved garbage collection - A new garbage collector based on the Linux kernel feature userfaultfd is coming to ART on Android 13 devices in an upcoming Google Play system update. The new garbage collector eliminates the read barrier and its fixed overhead per object loaded, reducing memory pressure and leading to as much as ~10% reduction in compiled code size. It’s more efficient at GC-time as well, since pages are freed as compaction progresses. Overall, the new garbage collector helps to save battery, avoid jank during GC operations, and protect apps from low-memory kills.

Optimizations throughout ART - In Android 13, ART makes switching to and from native code much faster, with JNI calls now up to 2.5x faster. We’ve also reworked the runtime’s reference processing to make it mostly non-blocking, which further reduces jank. We’ve exposed a new public API, Reference.refersTo(), which is useful in reclaiming unreachable objects sooner, and we’ve made the interpreter faster by optimizing class/method lookups. Lastly, ART now performs more byte-code verification at install time, avoiding the expense of verification at runtime and keeping app startup times fast. More here.

Get your apps ready!

Now with today’s public release of Android 13 to AOSP, we’re asking all Android developers to finish your compatibility testing and publish your updates as soon as possible, to give your users a smooth transition to Android 13.

To test your app for compatibility, just install it on a device running Android 13 and work through the app flows looking for any functional or UI issues. Review the Android 13 behavior changes for all apps first, to focus on areas where your current app could be affected. Here are some of the top changes to test:

Notifications runtime permission - Make sure you understand how this new permission works with your app’s notifications, and plan on targeting Android 13 (API 33) as soon as possible to help support users. More here.

Clipboard preview - Make sure your app hides sensitive data in Android 13’s new clipboard preview, such as passwords or credit card information. More here.

JobScheduler prefetch - JobScheduler now tries to anticipate the next time your app will be launched and will run any associated prefetch jobs ahead of that time. If you use prefetch jobs, test that they are working as expected. More here.

Remember to test the libraries and SDKs in your app for compatibility. If you find any SDK issues, try updating to the latest version of the SDK or reaching out to the developer for help.

Once you’ve published the compatible version of your current app, you can start the process to update your app's targetSdkVersion. Review the behavior changes for apps targeting Android 13 for this, and use the compatibility framework to help detect issues quickly.

Tablet and large-screens support

With Android 13 bringing a better experience to tablets, make sure your apps look their best. You can test large-screen features by setting up an Android emulator in Android Studio, or you can use a large screen device from our Android 13 Beta partners. Here are some areas to watch for:

Taskbar interaction - Check how your app responds when viewed with the new taskbar on large screens. Make sure your app's UI isn't cut off or blocked by the taskbar. More here.

Multi-window mode - Multi-window mode is now enabled by default for all apps, regardless of app configuration, so make sure the app handles split-screen appropriately. You can test by dragging and dropping your app into split-screen mode and adjusting the window size. More here.

Improved compatibility experience - if your app isn’t optimized for tablets yet, such as using a fixed orientation or not being resizable, check how your app responds to compatibility mode adjustments such as letterboxing. More here.

Media projection - If your app uses media projection, check how your app responds while playing back, streaming, or casting media on large screens. Be sure to account for device posture changes on foldable devices as well. More here.

Camera preview - For camera apps, check how your camera preview UI responds on large screens when your app is constrained to a portion of the screen in multi-window or split-screen mode. Also check how your app responds when a foldable device's posture changes. More here.

You can read more about the tablet features in Android 13 and what to test here.

What’s next?

Android 13 is rolling out to Pixel devices starting today.

If you’re currently enrolled in the Android Beta program, you’ll get the Android 13 final release and remain enrolled to receive ongoing Beta updates for Android 13 feature drops, starting later this year. If you’d like to opt out of ongoing Beta updates without needing to wipe your device, just visit the Android Beta site and opt out after you get the Android 13 final release and before taking the first beta for Android 13 feature drops.

System images for Pixel devices are available here for manual download and flash, and you can get the latest Android Emulator system images via the SDK Manager in Android Studio. If you're looking for the Android 13 source, you'll find it here in the Android Open Source Project repository under the Android 13 branches.

Thanks again for participating in our program of early previews and Betas! We're looking forward to seeing your apps on Android 13!

Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

Build apps for the new Samsung devices

11 August 2022

Posted by Diana Wong (Android Product Manager), Kseniia Shumelchyk (Developer Relations Engineer) and Sara Vickerman (Android Developer Marketing) This week, Samsung launched the latest devices to come to the Android ecosystem at their Galaxy Unpacked event. If you haven’t already, check out their two new foldables, the Galaxy Z Fold4 and Z Flip4, and their new lineup of watches running on Wear OS, the Galaxy Watch5 series. You can learn more about their announcements here.

Get your apps ready for foldables, like the Galaxy Z Fold4 and Z Flip4large screenlaunched Android 12LAndroid 13documentationmake your app fold awaretest your app on foldables
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Build exceptional Wear OS apps

The Wear OS platform expanded this week with the new and improved Galaxy Watch5 series. This lineup of devices builds on Samsung’s commitment to the wearable platform, which we saw last year when they launched Wear OS Powered by Samsung on the Galaxy Watch4 series.

If you’re looking to get started building for the latest Galaxy Watch 5 series, or any other Wear OS device, now is a great time to check out version 1.0 of Compose for Wear OS. This is the first stable release of our modern declarative UI toolkit designed to make building apps for Wear OS easier, faster, and more intuitive. The toolkit brings the best of Jetpack Compose to Wear OS, accelerating the development process so you can create beautiful apps with fewer lines of code.

The 1.0 release streamlines UI development by following the declarative approach and offering powerful Kotlin syntax. It also provides a rich set of UI components optimized for the watch experience and is accompanied by many powerful tools in Android Studio to streamline UI iteration. That’s why Compose for Wear OS is our recommended approach for building user interfaces for Wear OS apps.

We’ve built a set of materials to help you get started with Compose for Wear OS! Check out our curated learning pathway for a step-by-step journey, documentation including a quick start guide, the Compose for Wear OS codelab for hands-on experience, and samples available on Github.

Similarly to Compose for Wear OS, we’re building Wear OS Tile Components to make it faster and easier to build tiles. Tiles provide Wear OS users glanceable access to the information and actions they need in order to get things done quickly and they are one of the most used features on Wear OS. This update brings material components and layouts so you can create Tiles that embrace the latest Material design for Wear OS. Right now this is in beta, but keep a lookout for the launch announcement!

Another launch announcement to watch out for is Android Studio Dolphin, the latest release from Android Studio. Check out these features designed to make wearable app development easier:

Updated Wear OS emulator toolbar which now includes buttons and gestures available on Wear OS devices, such as palm and tilting and simulating two physical buttons.

Emulator pairing assistant to pair multiple Wear OS devices with a single virtual or physical phone. Android Studio remembers pairings after being closed and allows you to see Wear devices in the Device Manager.

Direct surface launch that allows you to create run/debug configurations for Wear OS tiles, watch faces, and complications, and launch them directly from Android Studio.

Between Jetpack Compose, Tile Components and Android Studio Dolphin, we are simplifying Wear OS app development. And, with the addition of the Galaxy Watch5 series to the Wear OS ecosystem, there are even more reasons to build an exceptional Wear OS app.

There’s never been a better time to start optimizing!

Form factors are having a major moment this year and Google is committed to helping you optimize and build across form factors with new content and tools, including sessions and workshops from this year’s Google I/O and new Android Studio features. Plus, we have Material Design guidance for large screens and Wear OS to help you in your optimization journey.

From the Watch5 series to the Z Fold4, Samsung’s Galaxy Unpacked brought us innovations across screen sizes and types. Prepare your app so it looks great across the entire Android device ecosystem!

Google Play Indie Games Festival: Finalists revealed

02 August 2022

Posted by Patricia Correa, Director, Global Developer Marketing The Indie Games Festival shines a spotlight on some of the best games on Google Play, and celebrates the passion and creativity that small games studios bring to gamers worldwide. This year we are hosting Festival in South Korea, Japan and Europe, for local developers and gamers from all over the world. Earlier this summer, we opened submissions, and today we’re revealing the finalists. Scroll down to see the shortlisted games! Join the finals September 3rd will be a jam packed day for indie games fans. Everyone is invited to attend the finals for the three Festivals, starting with South Korea at 2pm KST, followed shortly after by Japan at 3pm JST, and wrapping up with Europe at 11am CET.

The finals will be held in a custom virtual world where you can meet the people behind the finalist games, explore the titles, have fun with gamers from around the world, and be the first to discover the winners. The events will be hosted by Julia Hardy (Europe), Inho Jung (Korea) and Kajisac (Japan). At the European finals we will also reveal the class of 2022 of the Indie Games Accelerator, a program that helps small game studios take their game to the next level by providing them training and mentorship. Without further ado, please meet the finalists and join us in congratulating them!

Europe (in alphabetical order, also in this collection) Blacken Slash DT Space Races Dungeons of Dreadrock Find Hidden Objects Game (AR) Fury Unleashed Get Together: A Coop Adventure Gladiators: Survival in Rome Hygge is... Kingdom: Idle Gold Tycoon Kitty Q Light It Up: Energy Loops Luna Ravel Paths: Beatrice's adventure Pawnbarian Please, Touch The Artwork Quadline Rhythmer_ Square Valley sugar game Wingspan —--

Japan (in alphabetical order) A Year of Springs Attack on Tankette Brave Farm Survival Cards and Dragons Sealed Catastrophe Restaurant Crazy Donuts DeathAntique (Early Access not yet available globally) Dungeon and Gravestone exp!A GenEi AP: Empty Heart HUNGRY PIG Jack & Detectives Raspberry Mash SOULVARS Statute of Limitations "1 minute" world SUSHI ALONE Sushi Food Cart Time for Coffee in the Strange Forest Train's Run UnionShooter360 —--

Korea (in alphabetical order) Bingo Star Calibur League Connect Counting Star Cube Of Life: Resurrection Drawing Beats! Dungeon Rogue FIND ALL 3D Idle Ghost Hotel Lost Pages Meow Tower: Nonogram Merge of Mini : with your legion Pa!nt Random Card Shambles Soul Launcher SuperBattle The Greater Uglyhood Undead vs Demon More about the Indie Games Festival and the Indie Games Accelerator At Google Play we’re committed to helping developers of all sizes succeed on our platform. Programs like the Festival and the Accelerator are here to help small games studios:

Festival | Promotions & prizes that put your game in the spotlight: This contest is your chance to showcase your game to industry experts and players worldwide, and win prizes that will celebrate your art and promote your game.

Accelerator | Training and mentorship to supercharge your growth: Over a period of 10 weeks, you will get tailored online training sessions and mentorship from industry and Google experts to help you polish your game and scale with Google Play.

Learn more about the programs. For more updates about all of our programs, resources and tools for indie game developers, follow us on Twitter @GooglePlayBiz and Google Play business community on LinkedIn. How useful did you find this blog post? ★ ★ ★ ★ ★

Prepare your app to support predictive back gestures

29 July 2022

Posted by Jason Tang, Product Management, Diego Zuluaga, Developer Relations, and Michael Mauzy, Developer Documentation Since we introduced gesture navigation in Android 10, users have signaled they want to understand where a back gesture will take them before they complete it. As the first step to addressing this need, we've been developing a predictive back gesture. When a user starts their gesture by swiping back, we’ll show an animated preview of the destination UI, and the user can complete the gesture to navigate to that UI if they want – as shown in the following example.

Although the predictive back gesture won’t be visible to users in Android 13, we’re making an early version of the UI available as a developer option for testing starting in Beta 4. We plan to make the UI available to users in a future Android release, and we’d like all apps to be ready. We’re also working with partners to ensure it’s consistent across devices. Read on for details on how to try out the new gesture and support it in your apps. Adding support for predictive back gesture is straightforward for most apps, and you can get started today. We also encourage you to submit your feedback. Try out the predictive back gesture in Beta 4 To try out the early version of the predictive back gesture available through the developer option, you’ll need to first update your app to support the predictive back gesture, and then enable the developer option. Update your app to support predictive back gesture To help make predictive back gesture helpful and consistent for users, we're moving to an ahead-of-time model for back event handling by adding new APIs and deprecating existing APIs. The new platform APIs and updates to AndroidX Activity 1.6+ are designed to make your transition from unsupported APIs (KeyEvent#KEYCODE_BACK and OnBackPressed) to the predictive back gesture as smooth as possible. The new platform APIs include OnBackInvokedCallback and OnBackInvokedDispatcher, which AndroidX Activity 1.6+ supports through the existing OnBackPressedCallback and OnBackPressedDispatcher APIs. You can start testing this feature in two to four steps, depending on your existing implementation. 1. Upgrade to AndroidX Activity 1.6.0-alpha05. By upgrading your dependency on AndroidX Activity, APIs that are already using the OnBackPressedDispatcher APIs such as Fragments and the Navigation Component will seamlessly work when you opt-in for the predictive back gesture.

// In your build.gradle file:
dependencies {

// Add this in addition to your other dependencies
implementation "androidx.activity:activity:1.6.0-alpha05"

2. Opt-in for the predictive back gesture. Opt-in your app by setting the EnableOnBackInvokedCallback flag to true at the application level in the AndroidManifest.xml.

<application

...

android:enableOnBackInvokedCallback="true"

... >

...

</application>

If your app doesn’t intercept the back event, you're done at this step.

Note: Opt-in is optional in Android 13, and it will be ignored after this version.

3. Create a callback to intercept the system Back button/event. If possible, we recommend using the AndroidX APIs as shown below. For non-AndroidX use cases, check the platform API mentioned above.

This snippet implements handleOnBackPressed and adds the OnBackPressedCallback to the OnBackPressedDispatcher at the activity level.

val onBackPressedCallback = object: OnBackPressedCallback(true) {

override fun handleOnBackPressed() {

// Your business logic to handle the back pressed event

}

requireActivity().onBackPressedDispatcher

.addCallback(onBackPressedCallback)

4. When your app is ready to stop intercepting the system Back event, disable the onBackPressedCallback callback.

onBackPressedCallback.isEnabled = webView.canGoBack()

Note: Your app may require using the platform APIs (OnBackInvokedCallback and OnBackPressedDispatcher) to implement the predictive back gesture. Read our documentation for details.

Enable the developer option to test the predictive back gesture

Once you’ve updated your app to support the predictive back gesture, you can enable a developer option (supported in Android 13 Beta 4 and higher) to see it for yourself.

To test this animation, complete the following steps:

On your device, go to Settings > System > Developer options.
Select Predictive back animations.
Launch your updated app, and use the back gesture to see it in action.

Learn more

In addition to our detailed documentation, try out our predictive back gesture codelab in an actual implementation.

If you need a refresher on system back and predictive back gesture on Android, we recommend watching Basics for System Back.

feedback

Celebrating 5 years of Kotlin on Android

Android 13 is in AOSP!

Build apps for the new Samsung devices

Google Play Indie Games Festival: Finalists revealed

Prepare your app to support predictive back gestures

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