Posted by Anna-Chiara Bellini, Product Manager, Nick Butcher, Developer Relations
Today, we’re launching the beta release of Jetpack Compose, our new UI toolkit designed to make it faster and easier to build native apps across all Android platforms. Compose offers modern, declarative Kotlin APIs, helping you build beautiful, responsive apps with way less code. Built to integrate with existing Android apps and Jetpack libraries, you can adopt Compose at your own pace by combining Android Views and Compose.
With this beta release, Compose is API complete and has all the features you need to build production-ready apps. Beta also means API stable, so we won’t change or remove APIs. Now is a great time to start learning Compose and begin planning for how you will use it in an upcoming project or feature once it reaches 1.0 later this year.
Our team has been developing Compose in the open with feedback and participation from the community. Since open sourcing development in 2019, we’ve had 30 public releases, addressed over 700 external bugs, and accepted over 200 external contributions. We love seeing what you’ve been building with Compose and have used your feedback and feature requests to refine our APIs and prioritize our work. Since the alpha release, we’ve added and improved a number of new features:
For the beta release, we’ve been focused on ensuring API completeness; that all foundational APIs are in place for us to continue to build upon for 1.0 and beyond. We’ll work on stabilizing these APIs up to our 1.0 release with particular focus on app performance and accessibility.
Compose Beta is supported by the latest Canary of Android Studio Arctic Fox, which features many new tools:
🆕 Animation Preview: inspect and playback animations
🆕 Compose support in the Layout Inspector
🆕 Interactive preview: inspect and interact with a Composable in isolation
🆕 Deploy Preview: to deploy a Composable on your device without needing a full app
Live Literals on Android Emulator
Layout Inspector for Jetpack Compose
Jetpack Compose is designed to work seamlessly with Android Views, letting you adopt at your own pace. You can embed Compose UIs within Android Views and use Views within Compose. We lay out a number of adoption strategies in our interoperability documentation.
In addition to View interop, we integrate with common libraries to help you to add Compose to your existing applications—no need to rewrite or re-architect your app. We offer integrations with:
The MDC-Android Compose Theme Adapter and Accompanist libraries provide integrations with Material and AppCompat XML themes so you don’t need to duplicate theme definitions. Accompanist also offers wrappers for common image loading libraries.
Jetpack Compose is a declarative UI toolkit, a paradigm shift from the current View system, where you describe what your UI should look like for a given application state, not how to produce it. Compose takes care of updating your UI when your app state changes, so you don’t have to manipulate your UI into the desired state which can be tedious and error prone.
Built entirely in Kotlin, Compose takes advantage of its great language features to offer powerful, succinct, intuitive APIs. Coroutines for example enable us to write much simpler async APIs such as describing gestures, animation or scrolling. This makes it easier to write code that combines async events, like a gesture which hands off to an animation, all with cancellation and clean-up provided by structured concurrency.
To help you and your team learn all about Jetpack Compose, we’ve updated our learning pathway; a curated list of videos, hands-on codelabs and key docs to get you started. Today we’re releasing new & updated documentation guides, a number of screencasts and a new Animation Codelab to help dive deeper into how to build with Compose. From guidance on architecture, accessibility and testing, to deep dives into animation, lists or thinking in Compose, we have guides to help you get up to speed.
We also offer 8 official sample applications if you want to jump straight in and see Compose in action. We have simple to complex samples, each showcasing different APIs and use cases. Check the readme for more details.
If you’re ready to get started with Compose–and also want to win some prizes along the way, check out the #AndroidDevChallenge. For the next four weeks, we’ll have weekly challenges designed to give your very own insights into Jetpack Compose, so you can fly through your projects. Compete to win new prizes for each challenge, with over one thousand prizes to win including a Google Pixel 5. You can read more about the first weekly challenge - starting today - right here.
With Jetpack Compose reaching Beta—with stable APIs and feature complete for 1.0—it's a great time to start learning Jetpack Compose and planning how you might use it in an upcoming project. We’d love to hear your feedback on adopting Compose in your app or join the discussion in the Kotlin Slack #compose channel.
Posted by The Jetpack Compose Team
Jetpack Compose is Android’s modern toolkit for building native UI. It enables you to quickly bring your app to life with less code, powerful tools, and intuitive Kotlin APIs. With the Beta of Jetpack Compose released today, this is the perfect time to learn Compose and get ready to adopt it. To help you get started with Jetpack Compose we are launching a new #AndroidDevChallenge!
For the next four weeks, the #AndroidDevChallenge will be launching a series of weekly challenges to help you build better apps faster with Jetpack Compose. Oriented around “lift off insights," each challenge focuses on a new area of Compose, from animations to Material Theming, composables to lists and more! Compete to win new prizes for each challenge, with over one thousand prizes to win including a Pixel 5. 1 The first challenge starts today!
Every week brings a new challenge with its own rules and tasks. Every Wednesday starting today we’ll publish a blog post containing the full description of what you need to do and how long you have to complete the task. Each challenge will help you get familiar with the compose mental model and different Compose APIs - from basic Composables like Text and List, to state, animations and more.
Text
List,
Your solution to each challenge must be implemented in a GitHub repository. Make a copy of this Github repository template and follow the instructions in the README. The template contains a basic Hello World! in Compose and a continuous integration setup.
Hello World!
Let’s start the #AndroidDevChallenge with a bang bark: build a puppy adoption app! The app should contain an overview screen that displays a list of puppies, and a detail screen showing each puppy's details. You have until March 2nd, 23:59 PST to submit your entry. 2
Your UI must be fully built in Compose. Your submission will only be judged based on your app’s UI layer. To help you with the implementation, check out the Compose documentation on layouts, lists, text and navigation. For some paws-on learning try out the Compose pathway, with codelabs covering several topics useful in completing this challenge.
Are you a 🐱rather than a 🐶 person? Submissions for any type of pet adoption app are welcomed.
We look forward to seeing what you build!
Our first challenge kicks off with a prize that makes for the perfect sidekick as you’re flying through Compose: a limited edition trophy of our Jetpack Compose superhero, made of LEGO bricks. The first 500 people to successfully complete this challenge and submit their entry can add this trophy to their collection of Android figurines, showing off how you’re a winner for the first week’s #AndroidDevChallenge.
Week #1 prize: Jetpack Compose superhero
Community is at the heart of Jetpack Compose and your feedback helps us build a better product:
In less than 24 hours, we're giving you a backstage pass to Jetpack Compose, Android's modern toolkit for building native UIs, on #TheAndroidShow. Hosted by Kari Byron, you'll hear the latest on Jetpack Compose from the people who built it, plus a fireside interview with Android's Dave Burke.
Broadcasting live on February 24th at 9AM PT, you’ll be able to watch the show at goo.gle/TheAndroidShow, where you’ll also be able to find more information and links to all of the things we covered in the show. Or if you prefer, you can watch directly on YouTube or Twitter.
Got a burning Jetpack Compose question? Want to learn about annotating a function type with @ Composable? Or how to add a static parameter to Composable functions at the compiler level? Tweet us your Jetpack Compose questions now, using #TheAndroidShow. We’ve assembled a team of experts, ready to answer your questions live on #TheAndroidShow; tune in on February 24 to see if we cover your question!
Posted by Chet Haase, Developer Relations Engineer
We recently finished another series of MAD Skills videos - this time on Motion Layout. We covered ways in which you can use the API and the design tool to create rich, custom, and complex animations for your users.
Check out the episodes below to increase your knowledge and skills in different areas of the Motion Layout API and design tool. And watch the live Q&A episode, featuring engineers on the Motion Layout and Developer Relations teams.
This video explores how ConstraintSets are used to define different states of your UI that you animate between. Along the way, Sean shows how to use Motion Editor in Android Studio to create and edit these transitions.
This episode shows how to use Keyframes in a MotionLayout animation to customize the animation by altering the values of various properties over time. For example, you can use keyframes to change the path an object takes between start and end, instead of following just the default linear path it would follow otherwise.
In this third episode, Sean shows how you can add ConstraintSets, beyond the default two (start + end) to create more complex animations, or transitions that flow through multiple states between the start and end.
In the fourth episode, explains how to build a collapsible toolbar using Motion Layout, which is a common place where this API shines. Along the way, you'll learn how to animate custom attributes using MotionLayout.
The final episode of the series was a live Q&A, streamed and recorded on February 18th. It’s too late to see it or ask your questions live, but check out the recording to watch the conversation between me (asking the Qs) and Sean, John, and Nicolas (supplying the As).
There are plenty of other resources to learn more about how to use Motion Layout, besides this MAD Skills series, including:
The Motion Layout series may have ended, but there’s still plenty still to come in the MAD Skills series. Be sure to check the MAD Skills playlist on YouTube, the articles on Medium, or this handy landing page that points to all of it.
Posted by Dave Burke, VP of Engineering
Every day, Android apps help billions of people work, play, communicate, and create on a wide range of devices from phones and laptops to tablets, TVs, and cars. As more people come to rely on the experiences you build, their expectations can rise just as fast. It’s one of the reasons we share Android releases with you early: your feedback helps us build a better platform for your apps and all of the people who use them. Today, we’re releasing the first Developer Preview of Android 12, the next version of Android, for your testing and feedback.
With each version, we’re working to make the OS smarter, easier to use, and better performing, with privacy and security at the core. In Android 12 we’re also working to give you new tools for building great experiences for users. Starting with things like compatible media transcoding, which helps your app to work with the latest video formats if you don’t already support them, and easier copy/paste of rich content into your apps, like images and videos. We’re also adding privacy protections and optimizing performance to keep your apps responsive.
Today’s first preview is just the start for Android 12, and we’ll have lots more to share as we move through the release. Read on for a taste of what’s new in Android 12, and visit the Android 12 developer site for details on downloads for Pixel and release timeline. As always, it’s crucial to get your feedback early, to help us incorporate it into the final product, so let us know what you think!
Alongside the work we’re doing in Android 12, later this month we’ll have more to share on another important tool that helps you create great user experiences more easily: Jetpack Compose, our modern toolkit for building native UI. Join us on #TheAndroidShow for a behind-the-scenes look at Jetpack Compose, livestreamed on February 24 at 9AM PT, and tweet your Jetpack Compose questions using #TheAndroidShow to have them answered live on the show.
Privacy is at the heart of everything we do, and in Android 12 we’re continuing to focus on giving users more transparency and control while keeping their devices and data secure. In today’s release we’ve added new controls over identifiers that can be used for tracking, safer defaults for app components, and more. These changes may affect your apps, so we recommend testing as soon as possible. Watch for more privacy and security features coming in later preview releases.
Modern SameSite cookie behaviors in WebView - In line with changes to Chrome and other browsers, WebView includes new SameSite cookie behaviors to provide additional security and privacy and give users more transparency and control over how cookies can be used across sites. More here.
Restricted Netlink MAC - We’re continuing to help developers migrate to privacy-protecting resettable identifiers. In a multi-release effort to ease migration of device-scoped Netlink MAC, in Android 11 we restricted access to it based on API level 30, and in Android 12 we’re applying the restriction for all apps - regardless of targetSDK level. More here.
Safer exporting of components - To prevent apps from inadvertently exporting activities, services, and receivers, we’re changing the default handling of the android:exported attribute to be more explicit. With this change, components that declare one or more intent filters must now explicitly declare an android:exported attribute. You should inspect your components in the manifest in order to avoid installation errors related to this change. More here.
Safer handling of Intents - To make handling PendingIntents more secure, Android 12 requires apps to explicitly declare a mutability flag, either FLAG_MUTABLE or the new FLAG_IMMUTABLE, for each PendingIntent. More here.
You can read more about these and other privacy and security changes here.
In Android 12 we’re investing in key areas to help deliver a polished experience and better performance for users. Here are some of the updates so far.
Compatible media transcoding - With the prevalence of HEVC hardware encoders on mobile devices, camera apps are increasingly capturing in HEVC format, which offers significant improvements in quality and compression over older codecs. Most apps should support HEVC, but for apps that can’t, we’re introducing compatible media transcoding.
With this feature, an app that doesn’t support HEVC can have the platform automatically transcode the file into AVC, a format that is widely compatible. The transcoding process takes time, depending on the video and hardware properties of the device. As an example, a one minute 1080p video at 30fps takes around 9 seconds to transcode on a Pixel 4. You can opt-in to use the transcoding service by just declaring the media formats that your apps don't support. For developers, we strongly recommend that your apps support HEVC, and if that’s not possible, enable compatible media transcoding. The feature will be active on all devices using HEVC format for video capture. We'd love to hear your feedback on this feature. More here.
AVIF image support - To give you higher image quality with more efficient compression, Android 12 introduces platform support for AV1 Image File Format (AVIF). AVIF is a container format for images and sequences of images encoded using AV1. Like other modern image formats, AVIF takes advantage of the intra-frame encoded content from video compression. This dramatically improves image quality for the same file size when compared to older image formats, such as JPEG.
AVIF (18.2kB)
JPEG (20.7kB)
Credit: Image comparison from AVIF has landed by Jake Archibald
Foreground service optimizations - Foreground services are an important way for apps to manage certain types of user-facing tasks, but when overused they can affect performance and even lead to app kills. To ensure a better experience for users, we will be blocking foreground service starts from the background for apps that are targeting the new platform. To make it easier to transition away from this pattern, we’re introducing a new expedited job in JobScheduler that gets elevated process priority, network access, and runs immediately regardless of power constraints like Battery Saver or Doze. For back-compatibility, we’ve also built expedited jobs into the latest release of Jetpack WorkManager library. Also, to reduce distraction for users, we’re now delaying the display of some foreground service notifications by up to 10 seconds. This gives short-lived tasks a chance to complete before their notifications are shown. More here.
Rich content insertion - Users love images, videos and other expressive content, but inserting and moving this content in apps is not always easy. To make it simple for your apps to receive rich content, we’re introducing a new unified API that lets you accept content from any source: clipboard, keyboard, or drag and drop. You can attach a new interface, OnReceiveContentListener, to UI components and get a callback when content is inserted through any mechanism. This callback becomes the single place for your code to handle insertion of all content, from plain and styled text to markup, images, videos, audio files, and more. For back-compatibility, we’ve added the unified API to AndroidX. More here.
Audio-coupled haptic effect - In Android 12 apps can provide audio-coupled haptic feedback through the phone's vibrator. The vibration strength and frequency are derived from an audio session, allowing you to create more immersive game and audio experiences. For example, a video calling app could use custom ringtones to identify the caller through haptic feedback, or you could simulate rough terrain in a racing game. More here.
Multi-channel audio - Android 12 includes several enhancements for audio with spatial information. It adds support for MPEG-H playback in passthrough and offload mode, and the audio mixers, resamplers and effects have been optimized for up to 24 channels (the previous maximum was 8).
Immersive mode API improvements for gesture nav - We’ve simplified immersive mode so that gesture navigation is easier and more consistent, for example when watching a video, reading a book, or playing a game. We’re still protecting apps from accidental gestures when in full-screen experiences related to gaming, but in all other full-screen or immersive experiences (e.g. video viewers, reading, photo gallery), for apps targeting the new platform, we’re changing the default to allow users to navigate their phone with one swipe. More here.
Notification UI updates - We’re refreshing notification designs to make them more modern, easier to use, and more functional. In this first preview you’ll notice changes from the drawer and controls to the templates themselves. We’re also optimizing transitions and animations across the system to make them more smooth. As part of the updates, for apps targeting Android 12 we’re decorating notifications with custom content with icon and expand affordances to match all other notifications. More here.
Faster, more responsive notifications - When users tap a notification, they expect to jump immediately into the app - the faster the better. To meet that expectation, developers should make sure that notification taps trigger Activity starts directly, rather than using “trampolines” - an intermediary broadcast receiver or service - to start the Activity. Notification trampolines can cause significant delays and affect the user experience. To keep notifications responsive, Android 12 will block notification trampolines by preventing them from launching their target Activities, and we’re asking developers to migrate away from this pattern. The change applies only to apps targeting the new platform, but for all apps we’ll display a toast to make trampolines visible to you and to users. More here.
Improved Binder IPC calls - As part of our work on performance, we’ve put a focus on reducing system variability. We’ve taken a look at latency and workload distribution, and made optimizations that reduce the median experience from the tail end, or 99% percentile use case. In doing so, we’ve targeted improvements to system binder calls adding lightweight caching strategies and focusing on removing lock contention to improve latency distribution. This has yielded roughly a 2x performance increase on Binder calls overall, with significant improvements in specific calls, for example a 47x improvement in refContentProvider(), 15x in releaseWakeLock(), and 7.9x in JobScheduler.schedule().
refContentProvider()
releaseWakeLock()
JobScheduler.schedule()
We’re working to make updates faster and smoother by prioritizing app compatibility as we roll out new platform versions. In Android 12 we’ve made most app-facing changes opt-in to give you more time, and we’ve updated our tools and processes to help you get ready sooner. We’ve also added new functionality to Google Play system updates to give your apps a better environment on Android 12 devices.
More of Android updated through Google Play - We’re continuing to expand our investment in Google Play system updates (Project Mainline) to give apps a more consistent, secure environment across devices. In Android 12 we’ve added the Android Runtime (ART) module that lets us push updates to the core runtime and libraries on devices running Android 12. We can improve runtime performance and correctness, manage memory more efficiently, and make Kotlin operations faster - all without requiring a full system update. We’ve also expanded the functionality of existing modules - for example, we’re delivering our compatible media transcoding feature inside an updatable module.
Optimizing for tablets, foldables, and TVs - With more people than ever using apps on large-screen devices like foldables, tablets, and TVs, now is a great time to make sure your app or game is ready. Get started by optimizing for tablets and building apps for foldables. And, for the biggest screen in the home, the first Android 12 preview for Android TV is also available. In addition to bringing the latest Android features to the TV with this preview, you will also be able to test your apps on the all-new Google TV experience. Learn more on the Android TV Developers site and get started with your ADT-3 developer kit.
Updated lists of non-SDK interfaces - We’ve restricted additional non-SDK interfaces, and as always your feedback and requests for public API equivalents are welcome.
Easier testing and debugging of changes - To make it easier for you to test the opt-in changes that can affect your app, we’ve made many of them toggleable. WIth the toggles you can force-enable or disable the changes individually from Developer options or adb. Check out the details here.
App compatibility toggles in Developer Options.
Platform stability milestone - Like last year, we’re letting you know our Platform Stability milestone well in advance, to give you more time to plan for app compatibility work. At this milestone we’ll deliver not only final SDK/NDK APIs, but also final internal APIs and app-facing system behaviors. We’re expecting to reach Platform Stability by August 2021, and you’ll have several weeks before the official release to do your final testing. The release timeline details are here.
The Developer Preview has everything you need to try the Android 12 features, test your apps, and give us feedback. You can get started today by flashing a device system image to a Pixel 3 / 3 XL, Pixel 3a / 3a XL, Pixel 4 / 4 XL, Pixel 4a / 4a 5G, or Pixel 5 device. If you don’t have a Pixel device, you can use the 64-bit system images with the Android Emulator in Android Studio.
When you’re set up, here are some of the things you should do:
We’ll update the preview system images and SDK regularly throughout the Android 12 release cycle. This initial preview release is for developers only and not intended for daily or consumer use, so we're making it available by manual download only. You can flash a factory image to your Pixel device, or you can sideload an OTA image to a Pixel device running Android 11, in which case you won’t need to unlock your bootloader or wipe data. Either way, once you’ve manually installed a preview build, you’ll automatically get future updates over-the-air for all later previews and Betas. More here.
As we get closer to a final product, we'll be inviting consumers to try it out as well, and we'll open up enrollments through Android Beta at that time. Stay tuned for details, but for now please note that Android Beta is not currently available for Android 12.
For complete information, visit the Android 12 developer site.
Posted by Hoi Lam, Android App Quality
Since the launch of Android more than 10 years ago, the platform and the user’s expectations have grown. There are improvements from user experience through material design to the importance and advancement in privacy. We know you want your apps to offer a great user experience. At the same time, we also know that it’s not always straightforward to know which area to tackle first. That’s why we are launching a new App Quality section in our developer site to help you keep up-to-date with key aspects of app quality and provide related resources.
In the first release, we have updated the Core App Quality checklist to take into account recent Android releases as well as the current trends of the app ecosystem. Here are some highlights in this update:
Going forward, we aim to update this list on a quarterly basis to make sure this is up-to-date. In addition, we will be updating the quality checklists for other form factors.
We are working on additional tools and best practices to make it easier for you to build quality applications on Android. We can’t wait to introduce these new improvements to you. Stay tuned!
Posted by Ting-Yuan Huang, Software Engineer and David Winer, Product Manager
Today we are excited to announce the alpha of Kotlin Symbol Processing (KSP), an all-new tool for building lightweight compiler plugins in Kotlin. KSP offers similar functionality to KAPT, however it’s up to 2x faster, offers direct access to Kotlin compiler features, and is being developed with multiplatform compatibility in mind.
KSP is compatible with the Kotlin 1.4.30 release and onwards. You can check out the open source code and documentation in the KSP GitHub repository.
The #1 request we hear from Kotlin developers is to make build speeds faster. Many developers iterate on and deploy apps dozens of times a day, so having to sit around waiting for a slow build can be very time consuming. One of the biggest challenges with compiling Kotlin code is that Kotlin doesn’t have a native annotation processing system. Annotation processors like Room are ubiquitous on Android and rely on Java annotation processing compatibility through the Kotlin Annotation Processing Tool (KAPT). KAPT can be slow to run, though, since it requires generating intermediate Java stubs that can then be ingested by the Java annotation processing system.
When designing KSP, we thought about what annotation processing would look like for Kotlin if we built it from the ground up. KSP offers a powerful and yet simple API for parsing Kotlin code directly, dramatically reducing the build speed tax imposed by KAPT’s stub generation. Indeed, initial benchmarks with the Room library show that KSP is approximately 2x faster than KAPT.
To see what KSP looks like in action, download the KSP playground project from GitHub. In it you’ll find:
test-processor
workload
All of the logic for implementing the builder is in test-processor — for the consumer (workload), the only difference between using KAPT and KSP is a two-line build file change:
This is the goal of KSP: most Android app developers don’t need to worry about its internals; other than this one line change, a library that supports KSP looks just like a normal annotation processor, only it’s up to 2x faster. That said, using KAPT and KSP in the same module will likely slow down your build initially, so during this alpha period, it is best to use KSP and KAPT in separate modules.
As more annotation processors adopt KSP, we expect most of your modules to be able to use KSP as a near drop-in replacement for KAPT. For now, you can check out which annotation processors offer KSP support in this table. If a library that supports or is implementing support for KSP is missing from the table, please submit a pull request with your suggestion!
If you are an author of a library that currently uses annotation processing, you can find more information on how to make your library compatible with KSP in the quickstart and README guides.
For library authors, now that KSP is in alpha, it’s a great time to start looking closely at it and giving us feedback on the API in the KSP issue tracker. In addition, we regularly post release updates in the #ksp channel on Kotlin Slack. Since the developer preview last June, we’ve closed over 100 bugs and issues, dozens of which have been reported by the amazing community of Kotlin library developers.
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