Unfolding right now at #AndroidDevSummit!

Posted by Stephanie Cuthbertson, Director of Product Management

Today, at the Computer History Museum in Mountain View, CA, we kicked off the Android Dev Summit, taking a look back at the last 10 years of Android and then jumping into some important new features for Android developers. Here's a look at some of the things we shared!

Unfolding Android into new experiences

As early as Android 1.6, Android and our partners have contemplated different screen sizes and densities, enabling the platform to power a broad category of form factors and new experiences like Android TV, Android Auto, Wear OS and even Android apps on Chromebooks. Phone screens are an area where Android partners set the bar, introducing "phablets" when phone screens were small. Fast forward to today, when a phablet is... just a phone, a standard size users have come to love.

Now we see a Android device makers creating a new category: Foldables. Taking advantage of new flexible display technology, the screen can literally bend and fold.

There are two variants broadly speaking: two-screen devices and one-screen devices. When folded, foldables look like phones, fitting in your pocket or purse. When unfolded, their defining feature is what we call screen continuity. For example, start a video with the folded smaller screen - and later you can sit down and unfold the device to get a larger tablet-sized screen for a beautiful, immersive experience. As you unfold, the app seamlessly transfers to the bigger screen without missing a beat. We're optimizing Android for this new form factor. And, making changes to help developers everywhere take advantage of the possibilities this creates for amazing new experiences, new ways to engage and delight your users. Tune in to the Foldables session at Dev Summit this week to learn more. Expect to see Foldables coming from several Android manufacturers, including one Samsung previewed today and plans to offer next year.

Kotlin: updates to the fastest growing language

We made Kotlin a first class language on Android in 2017. This month we had over 118,000 new projects using Kotlin started in Android Studio - from those users who opt in to share metrics. That's a 10X increase from last year. It's become the fastest growing language in terms of growth of number of contributors on GitHub, and voted the #2 most loved language on Stack Overflow. In our surveys, the more developers use Kotlin, the higher their satisfaction.

Last week, JetBrains released the latest version of Kotlin, 1.3, which brings new language features, APIs, bug fixes, and performance improvements:

• Inline classes allow you to create a type which doesn't allocate unless boxed. For the constrained devices that Android apps target, avoiding allocation while retaining type-safety is a big advantage.
  
• Unsigned numbers are now part of the Kotlin standard library including UInt, UByte, and ULong. These new types are built using inline classes.
  
• Multiplatform code previously written for Android or the JVM can now also target Javascript or native. This unlocks the possibility of reusing parts of your codebase on even more platforms.
  
• Coroutines support is now stable. The language and library support combine to simplify how you interact with asynchronous operations and perform concurrent work–things that are essential to every Android app.

All of these new features of Kotlin 1.3 will be integrated into the Kotlin-specific APIs that we provide–a majority of which are through KTX extensions as part of Jetpack.

Android Jetpack: Navigation, Work Manager, and Slices

At Google I/O we announced Jetpack, the next generation of tools and Android APIs to accelerate Android application development. Jetpack builds on the foundations laid out by Support Library and Architecture. Already, 80% of top 1,000 apps and games are using one of the new Jetpack libraries in production.

This summer we moved AndroidX - Jetpack's evolution of the original Android Support Library - to public AOSP. This means you can see features and bug fixes implemented in real-time, and contribute to any of the AndroidX libraries. You can learn more about contributing here.

We've been working to get as much feedback and refinement as possible on two new Architecture Component libraries: Navigation and Work Manager, and we plan to move both to Beta this month. The Navigation Architecture Component offers a simplified way to implement Android's navigation principles in your application, using a single Activity. Plus, the new Navigation Editor in Android Studio creates and edits your navigation architecture. This eliminates navigation boilerplate, gives you atomic navigation operations, easier animated transitions and more. WorkManager makes it easy to perform background tasks in the most efficient manner, choosing the most appropriate solution based on the application state and device API level.

Navigation Editor

We're also excited to see Android Slices move to public Search experiments! At I/O this year we introduced Slices, a new way to bring users to your app. Slices are like a mini snippet of your app, where you can surface content and actions. You can book a flight, play a video, or call a ride. Slices is another example where we want to be open very early, but we want to take the time to get it right. We're moving into public EAP this month with Doist, Kayak and others. We'll run experiments surfacing Slices in Google search results. To learn more, there's also a session today at Dev Summit with more info and best practices.

Android Studio: focusing on productivity, build speed, quality and fundamentals

Android Studio is our official IDE for Android development. We asked where do you spend the most time? When we gather data from Android Studio's opted-in users we see that build time are getting faster with every release, sometimes as fast as 20%, but we also see build time getting slower and slower over time. So, how can both things be true? We've been digging in hard to understand.

It turns out build is a pretty complicated ecosystem. Developer choices makes a huge difference. Our developers are using a very broad (and growing) combination of OSes, custom plug-ins, annotation processors, languages. All of these can significantly affect times. In one case, a plugin some users like to add was silently slowing build speeds by up to 45%. Learning this, we realized we need build profiling and analysis tools so you can easily understand what's slowing your build down. We're also investing more in our own plugins to accelerate performance to make sure we continue to improve the performance of core build.

Android Studio 3.3 launches beta 3 today. In coming releases expect to see a strong focus on quality and fundamentals: reducing the number of crashes and hangs, optimizing memory usage, and fixing user-impacting bugs. We also announced today that we're making Android Studio an officially supported IDE on Chrome OS early next year; learn more here.

Android App Bundles and dynamic features

App sizes have grown dramatically, up 5x since 2012. But larger apps have downsides: lower install conversion rates, lower update rates, and higher uninstalls. This is why we built the Android App Bundle, the new publishing format that serves only the code and resources a user needs to run your app on their specific device; on average apps see 35% size savings compared to a universal APK. The app bundle also saves you time and effort with each release since you don't need to use incomplete solutions like multi-APK. Android Studio 3.2 brought full IDE support of app bundles, and there are now thousands of app bundles in production totaling billions of installs, including Google's apps like YouTube, Google Maps, Google Photos, and Google News.

The app bundle now supports uncompressed native libraries; with no additional developer work needed, the app bundle now makes apps using native libraries an average of 8% smaller to download and 16% smaller on disk on M+ devices.

Once you switch to the app bundle you can also start modularizing your app. With dynamic feature modules, you can load any app functionality on demand instead of at install time. You don't need to keep big features that are only used once, on every single device forever; dynamic features can be installed and uninstalled dynamically when your app requests them.

In-app Updates API

We've heard that you'd like more controls to ensure that users are running the latest and greatest version of your app. To address this, we're launching an In-app Updates API. We're testing the API with early access partners and will be launching it to all developers soon.

You'll have two options with this API; the first is a full-screen experience for critical updates when you expect the user to wait for the update to be applied immediately. The second option is a flexible update, which means the user can keep using the app while the update is downloaded. You can completely customize the update flow so it feels like part of your app.

Instant discovery

We're also making instant apps easier than ever to adopt. We recently made using web URLs optional, enabling you to take your existing play store deep link traffic and send users to your instant experience if it's available. Additionally, we've raised the instant app size limit to 10MB for the Try Now button on the Play Store and web banners to make it even easier to adopt.

In the Android Studio 3.3 beta, you can now build an instant-enabled app bundle. This means that you can now build and deploy both your Instant and installed experiences from a single Android Studio project, and include them in a single Android App Bundle. You only have to upload just ONE artifact for both instant and installed app.

As developers, your feedback has been critical in shaping these investment areas; you are part of how we work, from early ideas, to EAPs and canaries, Beta, and iterating after launch. We hope you join us for the next two days whether you're watching the 30+ sessions on the livestream, joining social, or with us in-person in Mountain View. From the team, a sincere thank you for all your thoughtful feedback and contributions. We hope you enjoy Android Dev Summit.

Kotlin Momentum for Android and Beyond

Posted by James Lau (@jmslau), Product Manager

Today marks the beginning of KotlinConf 2018 - the largest in-person gathering of the Kotlin community annually. 2018 has been a big year for Kotlin, as the language continues to gain adoption and earn the love of developers. In fact, 27% of the top 1000 Android apps on Google Play already use Kotlin. More importantly, Android developers are loving the language with over 97% satisfaction in our most recent survey. It's no surprise that Kotlin was voted as the #2 most-loved language in the 2018 StackOverflow survey.

Google supports Kotlin as a first-class programming language for Android development. In the past 12 months, we have delivered a number of important improvements to the Kotlin developer experience. This includes the Kotlin-friendly SDK, Android KTX, new Lint checks and various Kotlin support improvements in Android Studio. We have also launched Kotlin support in our official documentation, new flagship samples in Kotlin, a new Kotlin Bootcamp Udacity course, #31DaysOfKotlin and other deep dive content. We are committed to continuing to improve the Kotlin developer experience.

As the language continues to advance, more developers are discovering the benefits of Kotlin across the globe. Recently, we traveled to India and worked with local developers like Zomato to better understand how adopting Kotlin has benefited their Android development. Zomato is a leading restaurant search & discovery service that operates in 24 countries, with over 150 million monthly users. Kotlin helped Zomato reduce the number of lines of code in their app significantly, and it has also helped them find important defects in their app at compile time. You can watch their Kotlin adoption story in the video below.

Android Developer Story: Zomato uses Kotlin to write safer, more concise code.

Going beyond Android, we are happy to announce that the Google Cloud Platform team is launching a dedicated Kotlin portal today. This will help developers more easily find resources related to Kotlin on Google Cloud. We want to make it as easy as possible for you to use Kotlin, whether it's on mobile or in the Cloud.

Google Cloud Platform's Kotlin Homepage

Adopting a new language is a major decision for most companies, and you need to be confident that the language you choose will have a bright future. That's why Google has joined forces with JetBrains and established the Kotlin Foundation. The Foundation will ensure that Kotlin continues to advance rapidly, remain free and stay open. You can learn more about the Kotlin Foundation here.

It's an exciting time to be a Kotlin developer. If you haven't tried Kotlin yet, we encourage you to join this growing global community. You can get started by visiting kotlinlang.org or the Android Developer Kotlin page.

Verifying your Google Assistant media action integrations on Android

Posted by Nevin Mital, Partner Developer Relations

The Media Controller Test (MCT) app is a powerful tool that allows you to test the intricacies of media playback on Android, and it's just gotten even more useful. Media experiences including voice interactions via the Google Assistant on Android phones, cars, TVs, and headphones, are powered by Android MediaSession APIs. This tool will help you verify your integrations. We've now added a new verification testing framework that can be used to help automate your QA testing.

The MCT is meant to be used in conjunction with an app that implements media APIs, such as the Universal Android Music Player. The MCT surfaces information about the media app's MediaController, such as the PlaybackState and Metadata, and can be used to test inter-app media controls.

The Media Action Lifecycle can be complex to follow; even in a simple Play From Search request, there are many intermediate steps (simplified timeline depicted below) where something could go wrong. The MCT can be used to help highlight any inconsistencies in how your music app handles MediaController TransportControl requests.

Previously, using the MCT required a lot of manual interaction and monitoring. The new verification testing framework offers one-click tests that you can run to ensure that your media app responds correctly to a playback request.

Running a verification test

To access the new verification tests in the MCT, click the Test button next to your desired media app.

The next screen shows you detailed information about the MediaController, for example the PlaybackState, Metadata, and Queue. There are two buttons on the toolbar in the top right: the button on the left toggles between parsable and formatted logs, and the button on the right refreshes this view to display the most current information.

By swiping to the left, you arrive at the verification tests view, where you can see a scrollable list of defined tests, a text field to enter a query for tests that require one, and a section to display the results of the test.

As an example, to run the Play From Search Test, you can enter a search query into the text field then hit the Run Test button. Looks like the test succeeded!

Below are examples of the Pause Test (left) and Seek To test (right).

Android TV

The MCT now also works on Android TV! For your media app to work with the Android TV version of the MCT, your media app must have a MediaBrowserService implementation. Please see here for more details on how to do this.

On launching the MCT on Android TV, you will see a list of installed media apps. Note that an app will only appear in this list if it implements the MediaBrowserService.

Selecting an app will take you to the testing screen, which will display a list of verification tests on the right.

Running a test will populate the left side of the screen with selected MediaController information. For more details, please check the MCT logs in Logcat.

Tests that require a query are marked with a keyboard icon. Clicking on one of these tests will open an input field for the query. Upon hitting Enter, the test will run.

To make text input easier, you can also use the ADB command:

adb shell input text [query]

Note that '%s' will add a space between words. For example, the command adb shell input text hello%sworld will add the text "hello world" to the input field.

What's next

The MCT currently includes simple single-media-action tests for the following requests:

• Play
  
• Play From Search
  
• Play From Media ID
  
• Play From URI
  
• Pause
  
• Stop
  
• Skip To Next
  
• Skip To Previous
  
• Skip To Queue Item
  
• Seek To

For a technical deep dive on how the tests are structured and how to add more tests, visit the MCT GitHub Wiki. We'd love for you to submit pull requests with more tests that you think are useful to have and for any bug fixes. Please make sure to review the contributions process for more information.

Check out the latest updates on GitHub!

Android Pie SDK is now more Kotlin-friendly

Posted by James Lau, Product Manager (@jmslau)

When using the Java programming language, one of the most common pitfalls is trying to access a member of a null reference, causing a NullPointerException to be thrown. Kotlin offers protection against this by baking nullable and non-nullable types into the type system. This helps eliminate NullPointerExceptions from your code and improve your app's overall quality. When Kotlin code is calling into APIs written in the Java programming language, it relies on nullability annotations in those APIs to determine the nullability of each parameter and the return type. Unannotated parameters and return types are treated as platform types, which weakens the null-safety guarantee of Kotlin.

As part of yesterday's Android 9 announcement, we have also released a new Android SDK that contains nullability annotations for some of the most frequently used APIs. This will preserve the null-safety guarantee when your Kotlin code is calling into any annotated APIs in the SDK. Even if you are using the Java programming language, you can still benefit from these annotations by using Android Studio to catch nullability contract violations.

Not a breaking change

Normally, nullability contract violations in Kotlin result in compilation errors. But to ensure the newly annotated APIs are compatible with your existing code, we are using an internal mechanism provided by the Kotlin compiler team to mark the APIs as recently annotated. Recently annotated APIs will result only in warnings instead of errors from the Kotlin compiler. You will need to use Kotlin 1.2.60 or later.

Our plan is to have newly added nullability annotations produce warnings only, and increase the severity level to errors starting in the following year's Android SDK. The goal is to provide you with sufficient time to update your code.

How to use the "Kotlin-friendly" SDK

To get started, go to Tools > SDK Manager in Android Studio. Select Android SDK on the left menu, and make sure the SDK Platforms tab is open.

Use SDK Manager in Android Studio to install SDK for API Level 28 Revision 6

Check Android 8.+ (P) and click OK. This will install the Android SDK Platform 28 revision 6 if it is not already installed. After that, set your project's compile SDK version to API 28 to start using the new Android Pie SDK with nullability annotations.

Use the Project Structure Dialog to change your project's Compile Sdk Version to API 28

You may also need to update your Kotlin plugin in Android Studio if it's not already up-to-date. Make sure your Kotlin plugin version is 1.2.60 or later by going to Tools > Kotlin > Configure Kotlin Plugin Updates.

Once it's set up, your builds will start showing warnings if you have any code that violates nullability contracts in the Android SDK. An example of such a warning is shown below.

Sample warning from the Kotlin compiler when code violates a
recently added nullability contract in the Android SDK.

You will also start seeing warnings in Android Studio's code editor if you call an Android API with the incorrect nullability. An example is shown below.

Android Studio warning about passing a null reference to a parameter
annotated as a recently non-null type in the android.graphics.Path API.

Leveraging nullability annotations from the Java programming language

You can benefit from the new nullability annotations even if your code is in the Java programming language. By default, Android Studio will highlight any nullability contract violations with a warning, like the one below:

Android Studio showing a warning about nullability contract violation
in code written in the Java programming language

To ensure that you have this inspection enabled, you can go to the IDE's settings page and search for "Constant conditions & exceptions" inspection and make sure that item is checked.

Use the Inspections page under Settings to ensure the Constant conditions & exceptions code inspection is enabled.

If you are using the Java programming language, nullability contract violations will not produce any compiler warning or error. Only the in-IDE code inspections are available to flag these issues.

You can also run code inspections across your entire project and see the aggregated results. Click on Analyze > Inspect Code… to start.

What's Next

The Android SDK API surface is very large, and we have only annotated a small percentage of the APIs so far - there is still lots of work remaining. Over the next several Android SDK releases, we will continue to add nullability annotations to the existing Android APIs, as well as making sure new APIs are annotated.

With the "Kotlin-friendly" Android SDK, the nullability annotations in AndroidX (part of the Jetpack family), and Android KTX, we are continuing to improve the Android APIs for developers using Kotlin. If you have not yet tried Kotlin, we encourage you to try it. Not only can Kotlin make your code more concise, it can also improve the stability of your apps.

Happy Kotlin-ing!

A New Universal Music Player

Posted by
Nicole Borrelli, Android Developer, Programs Engineer

The Universal Android Music Player (or "UAMP") is a favorite on GitHub for music app developers with over 9,500 stars and 3,000 forks. Since UAMP was first released, Android development has changed significantly. ExoPlayer has improved, Architecture Components were introduced, and Kotlin became a first-class language for Android developers.

We decided that the best way to integrate the modern features for our beloved music app would be to re-write UAMP.

UAMP v2 was built from the ground up in Kotlin. The UI is built around ViewModels and LiveData. Playback, and particularly integration with MediaSessionCompat, was vastly simplified by utilizing the MediaSession extension of ExoPlayer.

We also added a bunch of new songs by The Kyoto Connection and Kai Engel.

There are some features from UAMP v1 that haven't been integrated into the new code yet. The missing features include Android TV with the Leanback library and remote playback via Google Cast. Even though these features aren't yet included in v2, we wanted to show you the new updates as soon as possible. The old code will continue to be available in the v1 branch on GitHub, so please take a look there to see how to use those features in a music app.

We would love your feedback on which features to add next. We are considering offline playback, improving the integration with Android Auto, and using the upcoming Navigation components of Jetpack for the UI. We'll be creating GitHub issues for features and improvements to help you let us know what is most important to you. Go vote on these features to let us know where we should focus our efforts.

We'd also like to invite you to open pull requests for bug fixes and features that are missing. See the contributions process for more information.

Grab the code from GitHub!

Learn Kotlin Fast with new Kotlin Bootcamp course

Posted by Aleks Haecky, Training Developer & Word Artist, Google+, LinkedIn, Medium

The Kotlin Bootcamp Udacity course is a free, self-paced online course that teaches you the basics of the Kotlin programming language. This introduction to Kotlin was created by Google experts in collaboration with Udacity and is for people who already know how to program.

The Kotlin language lets you create apps in less time, writing less code, and with fewer errors.

This modern object-oriented language offers a strong type system, type inference, null safety, properties, lambdas, extensions, coroutines, higher-order functions, and many other features. Kotlin is so concise that you can create complete data classes with a single line of code.

Kotlin is officially supported for building Android apps, fully interoperates with the Java programming language and libraries, and is included with IntelliJ and Android Studio.

In this course you will learn everything you need to program in Kotlin, including:

1. Basics: Write Kotlin statements and expressions in the IntelliJ REPL Kotlin interpreter using nullable and non-nullable variables, data types, operators, and control structures.
   
2. Functions: Create a main() function, create and call functions with default and variable arguments, pass functions as arguments to filters, program simple lambdas, function types, and compact single-expression functions.
   
3. Classes: Create a class with methods and properties. Implement constructors and init(). Learn about inheritance, interfaces, and abstract classes. Use the special purpose classes data, object, enum, and sealed.
   
4. Beyond the Basics: Dive deeper into Pairs, collections, and constants. Learn how to write extensions, implement generics, apply annotations, and use labeled breaks.
   
5. Functional Manipulation: Explore more about lambdas, higher-order functions, and inline.

You'll learn how to use extension functions to add helpful functionality to existing classes.

Extend built-in types:

fun Int.print() = println(this)
5.print() // prints 5

Extend Android classes:

fun Context.toast(text: CharSequence, duration: Int = Toast.LENGTH_SHORT): Toast {
   return Toast.makeText(this, text, duration).apply { show() }
}
toast("Hello Toast")

Extend your own classes:

class AquariumPlant(
       val color: String)

fun AquariumPlant.print() =
       println("Pretty Aquarium Plant")

val plant = AquariumPlant("green")
plant.print()
// prints -> Pretty Aquarium Plant

When you've completed the course, you will be able to create programs in Kotlin, taking advantage of the features and capabilities that make Kotlin unique.

The course is available free, online at Udacity; take it in your own time at your own pace.

Go learn how to build apps with less code at https://www.udacity.com/course/ud9011.

Google I/O 2018: What’s new in Android

Posted By Stephanie Cuthbertson, Product Management Director, Android



As Android has grown exponentially over the past ten years, we've also seen our developer community grow dramatically. In countries like China, India, and Brazil, the number of developers using our IDE almost tripled - in just two years. With such growth, we feel an even greater responsibility to invest in our developer experience. Guided by your feedback, we've focused our efforts on making mobile development fast and easy, helping you get more users by making apps radically smaller, and increasing engagement to keep users coming back. We're also pretty excited to see Android Things go to 1.0, creating new opportunities for you to develop - everything from major consumer devices, to cool remote control vehicles! As Day 1 of Google I/O kicks off, let's take a closer look at these major themes from the Developer Keynote:

Development: making mobile development fast and easy

• Android Jetpack — Today, we announced Android Jetpack, designed to accelerate your app development. Android Jetpack is the next generation of Android components, bringing together the benefits of the Support Library -- backwards compatibility and immediate updates -- to a larger set of components, making it quick and easy to build robust, high quality apps. Android Jetpack manages activities like background tasks, navigation, and lifecycle management, so you can eliminate boilerplate code and focus on what makes your app great. Android Jetpack is designed to work well with Kotlin, saving you even more code with Android KTX. The new Android Jetpack components released today include WorkManager, Paging, Navigation, and Slices.

• Kotlin — Since announcing support for Kotlin last year, the developer community has embraced the language. Most importantly, 95% of developers tell us they are very happy with using Kotlin for their Android development. And, the more developers use it, the more that number rises. The number of Play Store apps using Kotlin grew 6x in the last year. 35% of pro developers use it, and that number is growing each month. We are continuing to improve the Kotlin developer experience across our libraries, tooling, runtime, documentation and training. Android KTX is launching today as part of Android Jetpack to optimize the Kotlin developer experience. Tooling continues to improve with Android Studio, Lint support, and R8 optimizations. We have even tuned the Android Runtime (ART) in Android P, so that apps built with Kotlin can run faster. We have rolled out Kotlin code snippets in our official documentation, and are publishing a Kotlin version of the API reference documentation today. Earlier this week, we launched a new Kotlin Bootcamp on Udacity, which is a great resource for developers who are new to Kotlin. Lastly, we now have a Kotlin specialization in the Google Developers Experts Program. If you still haven't used Kotlin, I hope you you give it a try.
  
  


• Android Studio 3.2 Canary — Android Studio 3.2 features tools for Android Jetpack including a visual Navigation Editor and new code refactoring tools. The canary release also includes build tools to create the new Android App Bundle format, Snapshots in the Android Emulator for fast start time, new R8 optimizer for smaller download and install app code size, a new Energy Profiler to measure app impact on battery life, and more. You can download the latest version of Android Studio 3.2 from the canary channel download page.

Distribution: making apps radically smaller

• Android App Bundle & Google Play Dynamic Delivery — Introducing the new app model for Android. Dramatically reduce app size with a new publishing format—the Android App Bundle. In Android Studio, you'll now build an app bundle that contains everything your app needs for any device—all the languages, every device screen size, every hardware architecture. Then, when a user downloads your app, Google Play's new Dynamic Delivery will only deliver the code and resources matching the user's device. People see a smaller install size on the Play Store, can download your app more quickly, and save space on their devices.
  (Left) An example of all resources being delivered to a device via a legacy APK.
  
  (Right) An example of Dynamic Delivery serving just what’s needed to a device.


• Dynamic features via the Android App Bundle — The Android App Bundle also enables modularization so that you can deliver features on-demand, instead of during install. You can build dynamic feature modules in the latest Android Studio canary release. Join our beta program to publish them on Google Play.
  
  


• Google Play Console — New features and reports in the Play Console will help you improve your app's performance and grow your business. Read about the improvements to the dashboard, statistics, Android vitals, pre-launch report, acquisition report, and subscriptions dashboard. You can also upload, test, and publish apps using our new publishing format, the Android App Bundle.
  
  


• Google Play Instant — After launching in beta at GDC, today we announced that all game developers can build instant apps and we're thrilled to welcome Candy Crush Saga. Google Play Instant is now available on over 1 billion devices worldwide from the Play Store, search, social and most places you can tap a link. To make instant apps easier to build, we are launching a Unity plugin and beta integration with Cocos creator this week. Recently, we've started testing Google Play Instant compatibility with AdWords, allowing people to try out games directly from ads, across all the channels reached by Universal App campaigns.

Engagement: bringing users back more and more.

• Slices — Slices are UI templates that display a rich array of dynamic, and interactive content from your app, across Android and within Google surfaces. Slices can include live-data, scrolling content, inline actions, and deep-linking into your app so users can do everything from playing music to checking reservation updates. Slices can also contain interactive controls like toggles and sliders. You can get started building Slices today, and they will begin appearing for users soon.

• Actions — Actions are a new way to make your app's capabilities and content more accessible, so that people can easily get to it at the right moment. App Actions will appear to users based on usage and relevance, across multiple Google and Android surfaces, such as the Google Search App, the Play Store, the Google Assistant, and the Launcher. App Actions will be available for all developers to try soon, please sign up here if you'd like to be notified. You can also choose to build a Conversational Action as a companion experience to your app. This works on a variety of Assistant-enabled devices, such as speakers and smart displays. Both types of Actions use a new common catalog of intents.

Smarter devices: a powerful platform for IoT devices

• Android Things 1.0 — Android Things is Google's managed OS that enables developers to build and maintain Internet of Things devices at scale. Earlier this year at CES, we announced Lenovo, Harman, LG, and iHome are all building Assistant-enabled products powered by Android Things. After a developer preview with over 100,000 SDK downloads and feedback from more than 10,000 developers, we announced Android Things 1.0 this week. Four new System-on-Modules (SoMs) are now supported on the platform with guaranteed long-term support for three years and additional options for extended support, making it easier to go from prototypes to production. To make product development more seamless than ever, the accompanying Android Things Console is also ready for production. It helps developers easily manage and update their devices with the latest stability fixes and security updates provided by Google.

To get started with Android Things, visit our developer site and the new Community Hub to explore kits, sample code, community projects, and join Google's IoT Developers Community to stay updated. We introduced a limited program to partner with the Android Things team for technical guidance and support building your product. If your company is interested, sign up for our OEM Partner Program.

In addition to all these new developments, we're on the ground in over 140 countries, growing and expanding the developer community through programs such as Women Techmakers and Google Developer Groups (GDGs). We're investing in training programs like Google Developers Certification, building more courses through Udacity and other partners, to help developers deepen their technical capability. Today, 225 Google Developers Agency Program members from 50 agencies in 15 countries, are Android Certified. As part of our Google Developers Experts Program, we also now have more than 90 Android Developer Experts around the world actively supporting developers, start-ups and companies to build and launch innovative apps.

We also continue to recognize the great work from top app and game developers. This year, we held our third annual Google Play Awards. The nominees represent some of the best experiences available on Android, with an emphasis on overall quality, strong design, technical performance, and innovation. Check out the winners and nominees.

During Google I/O, attendees and viewers have an opportunity to dive deep with 48 Android & Play breakout sessions. Thank you for all your wonderful feedback, and please keep giving us your advice on where we should go next.

Introducing Android KTX: Even Sweeter Kotlin Development for Android

Posted by Jake Wharton (@JakeWharton), Florina Muntenescu (@FMuntenescu) & James Lau (@jmslau)

Today, we are announcing the preview of Android KTX - a set of extensions designed to make writing Kotlin code for Android more concise, idiomatic, and pleasant. Android KTX provides a nice API layer on top of both Android framework and Support Library to make writing your Kotlin code more natural.

The portion of Android KTX that covers the Android framework is now available in our GitHub repo. We invite you to try it out to give us your feedback and contributions. The other parts of Android KTX that cover the Android Support Library will be available in upcoming Support Library releases.

Let's take a look at some examples of how Android KTX can help you write more natural and concise Kotlin code.

Code Samples Using Android KTX

String to Uri

Let's start with this simple example. Normally, you'd call Uri.parse(uriString). Android KTX adds an extension function to the String class that allows you to convert strings to URIs more naturally.

Kotlin	Kotlin with Android KTX
val uri = Uri.parse(myUriString)	val uri = myUriString.toUri()

Edit SharedPreferences

Editing SharedPreferences is a very common use case. The code using Android KTX is slightly shorter and more natural to read and write.

Kotlin	Kotlin with Android KTX
sharedPreferences.edit() .putBoolean(key, value) .apply()	sharedPreferences.edit { putBoolean(key, value) }

Translating path difference

In the code below, we translate the difference between two paths by 100px.

Kotlin	Kotlin with Android KTX
val pathDifference = Path(myPath1).apply { op(myPath2, Path.Op.DIFFERENCE) } val myPaint = Paint() canvas.apply { val checkpoint = save() translate(0F, 100F) drawPath(pathDifference, myPaint) restoreToCount(checkpoint) }	val pathDifference = myPath1 - myPath2 canvas.withTranslation(y = 100F) { drawPath(pathDifference, myPaint) }

Action on View onPreDraw

This example triggers an action with a View's onPreDraw callback. Without Android KTX, there is quite a bit of code you need to write.

Kotlin

view.viewTreeObserver.addOnPreDrawListener( object : ViewTreeObserver.OnPreDrawListener { override fun onPreDraw(): Boolean { viewTreeObserver.removeOnPreDrawListener(this) actionToBeTriggered() return true } })

Kotlin with Android KTX

view.doOnPreDraw { actionToBeTriggered() }

There are many more places where Android KTX can simplify your code. You can read the full API reference documentation on GitHub.

Getting Started

To start using Android KTX in your Android Kotlin projects, add the following to your app module's build.gradle file:

repositories {
    google()
}

dependencies {
    // Android KTX for framework API
    implementation 'androidx.core:core-ktx:0.1'
    ...
}

Then, after you sync your project, the extensions appear automatically in the IDE's auto-complete list. Selecting an extension automatically adds the necessary import statement to your file.

Beware that the APIs are likely to change during the preview period. If you decide to use it in your projects, you should expect breaking changes before we reach the stable version.

androidx: Hello World!

You may notice that Android KTX uses package names that begin with androidx. This is a new package name prefix that we will be using in future versions of Android Support Library. We hope the division between android.* and androidx.* makes it more obvious which APIs are bundled with the platform, and which are static libraries for app developers that work across different versions of Android.

What's Next?

Today's preview launch is only the beginning. Over the next few months, we will iterate on the API as we incorporate your feedback and contributions. When the API has stabilized and we can commit to API compatibility, we plan to release Android KTX as part of the Android Support Library.

We look forward to building Android KTX together with you. Happy Kotlin-ing!