Category Archives: Android Developers Blog

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Meet the finalists of the Google Play Indie Games Festival

Posted by Leticia Lago, Head of Developer Marketing, EMEA

At the start of this year we opened submissions for 2020’s Google Play Indie Games Festival - an international competition celebrating incredible indie games from Europe, Japan and South Korea.

We’ve received hundreds of fantastic submissions that showcase the technical abilities and groundbreaking creativity of independent studios. Many thanks to everyone who submitted their game. After some hard choices and late nights, we’re happy to announce our 20 finalists in each region.

Please check out the games below (in alphabetical order); each one is a true work of art. They will be receiving promotions and prizes to help them grow their business. They’ll also be competing in the Finals for the top prizes.

While this is a happy announcement, we must also inform you that we will be unable to hold the Finals as planned on April 25 in Poland, Japan and South Korea due to the COVID-19 situation. We will be postponing the events until further notice, as the health and safety of finalists, jury members, players and others involved is our top priority. Please stay tuned for further announcements.

Europe*

60 Parsecs! by Robot Gentleman

Aisle Trial by Jake Matthews-Belcher

Alien Escape by Korion Games

Alt-Frequencies by Accidental Queens

Bad North by Rawfury

Bounce that Bird! by Affinity Project

Cessabit: a Stress Relief Game by Tepes Ovidiu

Color Spots by UX Apps

Cookies Must Die by Rebel Twins

Demons Never Lie by Maika Hernandez

Doors: Awakening by Big Loop

Faraway: Galactic Escape by Pine Studio

inbento by Afterburn

My Diggy Dog 2 by King Bird Games

The White Door by Rusty Lake

Tiny Tomb: Dungeon Explorer by Tinycorp

Traffix by Infinity Games

Tricky Castle by Team Tricky

Unhatched by Filip Loster

Void Tyrant by Quite Fresh

Japan

Amayadori by CHARON・Yanase

CUBE GARDEN by Fukudanuki

GIGAFALL by Shiki Game Studio

GummyShooter by simatten

Home Fighter by hap Inc.

Matsuro Palette by SleepingMuseum

METBOY! by REBUILD GAMES

Mocha - Dagsaw Puzzle - by Kotoriyama, Inc.

MonsterTrader by Mitsuhiro Okada

Overturn by Katsu Matsuda

Shiritori - The Word Chain Game by Baton

Snowman Story by Odencat

SOUND JOURNEY SCHOOL WANDERER by SOUND JOURNEY

TAP! DIG! MY MUSEUM! by oridio Inc.

Teiji Taisha Online by toru sugitani

The Final Taxi by Zxima.LLC

Uncrowned by NESTOPI Inc.

Wasurenaide, otona ni natte mo by GAGEX Co.,Ltd.

World for Two by Seventh rank

Zelle by Odencat Fuming

South Korea

Castle Defense Online by BlackHammer

CAT THE DJ by CATSBY STUDIO

DiceEmpire by Banjiha Games

Domino City by Bad Beans

DUST by I-eye studio

Electroad by Night Owl Studio

Extreme football by 9M Interactive

From Earth by Kentauros Entertainment

Great Sword - Stickman Action RPG by Olivecrow

Heroes Restaurant by Team Tapas

Little Boy by 39Studio

Magic Survival by LEME

Mayday Memory by StoryTaco.inc

Petrider by Ddookdak studio

Project Mars by Moontm

QV by Izzle

Sand Shark : The Boy and The Sea by GABANGMAN STUDIO

Staroid : Brick breaker shooter by Spring Games

Sword Master Story by CodeCAT

Undestroyed by Keymaker games

The competition was open to indie developers from the following European countries: Austria, Belgium, Belarus, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Israel, Italy, Latvia, Lithuania, Netherlands, Norway, Poland, Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Turkey, Ukraine, and the United Kingdom (including Northern Ireland).

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Source: Android Developers Blog

Run ARM apps on the Android Emulator

Posted by Michael Hazard

As part of the Android 11 developer preview we’ve released Android 11 system images, which are capable of executing ARM binaries with significantly improved performance. Previously, developers who were dependent on ARM libraries and could not build an x86 variant of their app either had to use system images with full ARM emulation, which are much slower than x86 system images when run on x86-based computers, or resort to physical devices. The new Android 11 system images are capable of translating ARM instructions to x86 without impacting the entire system. This allows the execution of ARM binaries for testing without the performance overhead of full ARM emulation.

The new Android 11 (Google APIs) x86 system image supports ARM ABIs, while the older Android Oreo system image does not

Details

The significance of this may require a bit of context, especially if you build apps exclusively with Kotlin or the Java programming language. Unlike Kotlin or the Java programming language, both of which execute on the Android Runtime (ART), any C++ in your Android app compiles directly into machine instructions. This means that it needs to be compiled differently based on the architecture of the target device. Mobile phones tend to have ARM processors; consequently, many C++ dependencies you might add to your app, like a camera barcode scanner library, are only compatible with ARM processors. This is a problem if you develop on a computer with an x86-based processor, as it would prevent you from running your app.

Previously, if you wanted to get around this limitation and execute an app built for ARM on your x86 machine, you would have had to use an emulator system image with full ARM emulation. Due to the overhead of translating an entire system’s worth of ARM instructions to x86, emulator system images with full ARM emulation tend to run much slower than x86-based system images when run on x86 host machines. Additionally, emulator system images with full ARM emulation cannot take advantage of the hardware acceleration and CPU virtualization technologies provided by x86 processors.

The new ARM-compatible Android 11 system images allow the entire system to run x86 natively and take advantage of virtualization technologies as usual. When an app’s process requires an ARM binary, the binary is translated to x86 within that process exclusively. This allows the rest of the process to continue executing in x86, including the Android Runtime (ART), and other performance-critical libraries like libGLES and libvulkan. In addition to this, the translator avoids expensive memory access instrumentation and the associated performance hit by avoiding the execution of low-level hardware-specific libraries. These new emulator system images can be used both locally and on your own continuous integration infrastructure. This is possible thanks to collaboration with ARM Limited.

Going Forward

If you have previously chosen physical devices over the emulator due to the lack of performant ARM support, try out the Android 11 system images, which are now available alongside the Android 11 Developer Preview. These system images can be downloaded in Android Studio via either the SDK Manager or the Android Virtual Device Manager.

Using the Android Virtual Device Manager to create an AVD that runs Android 11

Once you get your app running on the emulator, consider adapting it for Chrome OS. Chrome OS also supports the execution of Android apps built for ARM on x86 laptops. Building for Chrome OS provides access to a substantial ecosystem of larger screen devices, allowing your application to reach even more users globally.

This technology should enable more developers to test with the Android Emulator. That said, we still recommend that developers publish both x86 and ARM ABI variants of their apps to achieve the best physical device performance and reach as many users as possible. Going forward, we plan to roll this technology out across a wider variety of API levels and ensure that it supports testing all use cases that a physical device would. Given that this is a new technology, please let us know of any problems via our Issue Tracker.

Note that the ARM to x86 translation technology enables the execution of intellectual property owned by Arm Limited. It will only be available on Google APIs and Play Store system images, and can only be used for application development and debug purposes on x86 desktop, laptop, customer on-premises servers, and customer-procured cloud-based environments. The technology should not be used in the provision of commercial hosted services.

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

Source: Android Developers Blog

Google for Games Developer Summit March 2020

Posted by Greg Hartrell, Head of Product Management, Games on Android & Google Play

While we're sorry we didn't get to see you all in person at GDC, we hope you are all staying healthy and safe. As many of us look to press on with work as much as possible, we’d like to share with you what our teams have been working on at the digital Google for Games Developer Summit. We couldn’t be happier with the continued growth of the vibrant Android gaming ecosystem. In fact, Android remains the world's most popular mobile platform with more than 2.5 billion monthly active devices and great news for game developers, we’re seeing more than 1.4 trillion minutes played per month in your games on Google Play. It’s important to us that our platforms are highly useful to every kind of game developer, so our payment system helps games monetize in more than 65 countries. Moreover, we offer our users more than 275 local forms of payment, including more than 180 carrier billing options, with gift cards sold in over 900 thousand unique retail locations worldwide.

Across Android and Google Play, our mission is to deliver the best platform to build, discover, and experience games. Specifically, we’re working on ways to help you increase the reach of your games and manage the fragmentation of the Android ecosystem. We’re also focused on helping you access a wider player base, once you’ve made a great game and are ready to get it out there. Last year, we shared that we’re investing heavily in our games efforts to address your challenges in these areas, and now we are excited to share several new tools and services built specifically with game developers in mind.

Catch up on everything shared at g.co/gamedevsummit.

New Android tools for mobile game development

A major area of investment for us has been making it easier for developers to build and optimize games for Android. Here’s a round-up of several new tools we’re releasing:

Android Studio Profilers: We’ve overhauled our Android Studio System Trace profiler to allow you to inspect and visualize in fine detail how your code is being executed. We also added native memory profiling capabilities so you can see how your game is allocating memory and find memory leaks. Download Android Studio 4.1 Canary and watch the session.
Android Game Development Extension for Visual Studio: We’re introducing a new tool to make it easy to add Android support for your cross-platform games. This integrates easily with existing Visual Studio-based workflows so now you can conveniently generate APKs, deploy to Android devices or an emulator, and debug your Android game from within Visual Studio. Apply for the developer preview and watch the session.
Android GPU Inspector: Our new Android GPU Inspector enables you to look deeply into an Android GPU and see detailed information about your game’s render stages and GPU counters. Now graphics engineers are empowered with information and insights to optimize their game for better frame rates and more battery life. Apply for the developer preview and watch the session.
Game Package Registry for Unity by Google: Our new package registry consolidates various Google APIs, starting with Google Play Billing, Android App Bundles, Play Asset Delivery, Play Instant, and Firebase for Games, all in one place. Learn more and watch the session.
Crytek announces Android support: CRYENGINE is known as a high performance game engine for PCs and game consoles and will be adding a full Android pipeline to their engine this summer. Learn more.

New ways to reach more devices & users

We’ve been working to help developers scale their reach to a growing player-base across the Android ecosystem. Today, we’re introducing a few new tools to help your development process and provide greater insights into your game’s performance.

Google Play Asset Delivery: Introducing a new set of delivery features for games services, building on our App Bundle infrastructure to give you free, dynamic delivery of the right game assets to the right devices at the right time. All of this allows players to get into your game faster while assets are being downloaded, while you cut the costs of hosting and delivering d game resources. Learn more and watch the session.
Android vitals native crash symbolication: Now you can debug your native crashes more easily with support for native symbols in Play Console. Simply upload your native debug symbols to get the benefits in Android Vitals. Apply for the open beta and watch the session.
Android vitals performance insights with Android Performance Tuner: We’re making it possible to optimize your frame rate and fidelity across many devices at scale with new performance insights in Android vitals. For those in our developer preview, you can unlock this by integrating the new Android Performance Tuner into your game: a new library in the Android Game SDK. Apply for the developer preview and watch the session.
Play Billing Library 2 for Unity developers: Game developers using Unity can now access all of Play Billing Library 2's features, such as allowing users to pay with cash and surfacing IAPs outside of the game. This is the best way for Unity developers to prepare for Play’s Billing Library version requirements in 2021. Learn more.

New ways to reach more devices and win go-to-market

The Google Play store is shifting to be more gameplay centric by showing more visuals that demonstrate gameplay and a new system of tags to help users learn more about specific game traits and aid in exploration. Learn how you can ensure your game is of high-quality and leverage various features and new services to help you succeed in your go-to-market activities.

Emphasis on quality: We continue to emphasize high quality gaming experiences across Google Play, to encourage immersive gameplay with strong technical performance and being free of crashes. Learn more.
Pre-registration: Hundreds-of-millions of players use pre-registration campaigns on Google Play each year, making it an effective way to expand the reach on launch. We’ll soon be rolling out day 1 auto-installation for all pre-registration games, to help you build early consumer awareness and capture pre-launch demand.
Play Pass: Late last year we launched Play Pass in the US market as a subscription service providing users with access to hundreds of great apps and games on Google Play, completely free of ads and in-app purchases. Learn more and express interest.

Thanks for your support in continuing to build incredible games. Make sure to try some of the new tools and services we just released and catch the full playlist of mobile developer sessions. If you’re interested in sharing feedback to help shape the development of cutting edge features, apply to join our developer preview programs from Android and Google Play. You can also learn about all of the offerings we have to help game developers building on Android at d.android.com/games.

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Source: Android Developers Blog

Android 11: Developer Preview 2

Posted by Dave Burke, VP of Engineering

Android 11 Dial logo

It’s been a difficult few months for many around the world. The Android team at Google is a global one, and we, like many of you, are learning how to adapt to these extraordinary times. We want to thank you, our developer community, who have given us valuable feedback on Android 11 amidst these circumstances. We hope you, your families and colleagues are all staying well.

Just as many of you are trying to press on with work where possible, we wanted to share the next milestone release of Android 11 for you to try. It’s still an early build, but you can start to see how the OS is enabling new experiences in this release, from seamless 5G connectivity to wrapping your UI around the latest screens, to a smarter keyboard and faster messaging experience.

There’s a lot to check out in Developer Preview 2 - read on for a few highlights and visit the Android 11 developer site for details. Today’s release is for developers only and not intended for daily or consumer use, so we’re making it available by manual download and flash only for Pixel 2, 3, 3a, or 4 devices. To make flashing a bit easier, you can optionally get today’s release from the Android Flash Tool. For those already running Developer Preview 1 or 1.1, we’re also offering an over-the-air (OTA) update to today’s release.

Let us know what you think, and thank you to everyone who has shared such great feedback so far.

New experiences

5G state API - DP2 adds a 5G state API to let you quickly check whether the user is currently on a 5G New Radio or Non-Standalone network. You can use this to highlight your app’s 5G experience or branding when the user is connected. You can use this API together with the 5G dynamic meteredness API and bandwidth estimator API, as well as existing connectivity APIs, to take advantage of 5G’s improved speeds and latency.

Hinge angle for foldables - A top request for foldable devices has been an API to get the angle of the device screen surfaces. Android 11 now supports a hinge angle sensor that lets apps query directly or through a new AndroidX API for the precise hinge angle, to create adaptive experiences for foldables.

Call screening service improvements - To help users manage robocalls, we’re adding new APIs to let call-screening apps do more to help users. In addition to verifying an incoming call’s STIR/SHAKEN status (standards that protect against caller ID spoofing) as part of its call details, call-screening apps can report a call rejection reason. Apps can also customize a system-provided post call screen to let users perform actions such as marking a call as spam or adding to contacts. We’ll have more to share on this soon.

New ops and controls in Neural Networks API - Activation functions control the output of nodes within a neural network. At Google AI, we discovered a swish activation function allowing for faster training time and higher accuracy across a wide variety of tasks. In Android 11, we’re adding a computationally efficient version of this function, the hard-swish op. This is key to accelerating next-generation on-device vision models such as MobileNetV3 which forms the base model for many transfer learning use cases. Another major addition is the Control ops enabling more advanced machine learning models that support branching and loops. Finally, we’ve also added new execution controls to help you minimize latency for common use cases: Asynchronous Command Queue APIs reduce the overhead when running small chained models. See the NDK sample code for examples using these new APIs.

Privacy and security

We’re adding several more features to help keep users secure and increase transparency and control. Give these a try with your apps right away and let us know what you think.

Foreground service types for camera and microphone - in Android 10 we introduced the manifest attribute foregroundServiceType as a way to help ensure more accountability for specific use-cases. Initially apps could choose from “location” and several others. Now in Android 11 we’re adding two new types - “camera” and “microphone”. If your app wants to access camera or mic data from a foreground service, you need to add the foregroundServiceType value to your manifest.

Scoped storage updates- We’re continuing to iterate on our work to better protect app and user data on external storage. In this release we’ve made further improvements and changes, such as support to migrate files from the legacy model to the new scoped storage model, and better management of cached files. Read more here and watch for more enhancements in subsequent updates.

Read more about these and other Android 11 privacy features here.

Polish and quality

Synchronized IME transitions - A new set of APIs let you synchronize your app’s content with the IME (input method editor, aka soft keyboard) and system bars as they animate on and offscreen, making it much easier to create natural, intuitive and jank-free IME transitions. For frame-perfect transitions, a new insets animation listener notifies apps of per-frame changes to insets while the system bars or the IME animate. Additionally, apps can take control of the IME and system bar transitions through the WindowInsetsAnimationController API. For example, app-driven IME experiences let apps control the IME in response to overscrolling the app UI. Give these new IME transitions a try and let us know what other transitions are important to you.

Synchronized IME transition through insets animation listener.

App-driven IME experience through WindowInsetsAnimationController.

Variable refresh rate - Apps and games can now set a preferred frame rate for their windows. Most Android devices refresh the display at 60Hz refresh rate, but some devices support multiple refresh rates, such as 90Hz as well as 60Hz, with runtime switching. On these devices, the system uses the app’s preferred frame rate to choose the best refresh rate for the app. The API is available in both the SDK and NDK. See the details here.

Resume on reboot - Android 11 improves the experience of scheduled overnight over-the-air software updates. Like in previous versions of Android, the device must still reboot to apply the OTA update, but with resume on reboot, apps are now able to access Credential Encrypted (CE) storage after the OTA reboot, without the user unlocking the device. This means apps can resume normal function and receive messages right away - important since OTA updates can be scheduled overnight while the device might be unattended. Apps can still support Direct Boot to access Device Encrypted (DE) immediately after all types of reboot. Give resume on reboot a try by tapping “Restart after 2AM” with your next Developer Preview OTA update, more details here.

Camera support in Emulator - The Android emulator now supports front and back emulated camera devices. The back camera supports Camera2 API HW Level 3 (includes YUV reprocessing, RAW capture). It’s a fully CTS-compliant LEVEL_3 device that you can use to test advanced features like ZSL and RAW/DNG support. The front camera supports FULL level with logical camera support (one logical device with two underlying physical devices). This camera emphasizes logical camera support, and the physical camera devices include narrow and wide field of view cameras. With this emulated camera support, you can build and test with any of the camera features added in Android 11. More details coming soon.

App compatibility

We’re working to make updates faster and smoother by prioritizing app compatibility as we roll out new platform versions. In Android 11 we’ve added new processes, tools, and release milestones to minimize the impact of platform updates and make them easier for developers.

With Developer Preview 2, we’re well into the release and getting closer to Beta. so now is the time to start your compatibility testing and identify any work you’ll need to do. We recommend doing the work early, so you can release a compatible update by Android 11 Beta 1. This lets you get feedback from the larger group of Android 11 Beta users.

When we reach Platform Stability, system behaviors, non-SDK greylists, and APIs are finalized. At this time, plan on doing your final compatibility testing and releasing your fully compatible app, SDK, or library as soon as possible so that it is ready for the final Android 11 release. More on the timeline for developers is here.

You can start compatibility testing on a Pixel 2, 3, 3a, or 4 device, or you can use the Android Emulator. Just flash the latest build, install your current production app, and test all of the user flows. There’s no need to change the app’s targetSdkVersion at this time. Make sure to review the behavior changes that could affect your app and test for impacts.

To help you with testing, we’ve made many of the breaking changes toggleable, so you can force-enable or disable them individually from Developer options or adb. Check out the details here. Also see the greylists of restricted non-SDK interfaces, which can also be enabled/disabled.

App compatibility toggles in Developer Options.

Get started with Android 11

Developer Preview has everything you need to try the Android 11 features, test your apps, and give us feedback. Just download and flash a device system image to a Pixel 2 / 2 XL, Pixel 3 / 3 XL, Pixel 3a / 3a XL, or Pixel 4 / 4 XL device, or set up the Android Emulator through Android Studio. Next, update your Android Studio environment with the Android 11 Preview SDK and tools, see the set up guide for details.

As always, your feedback is crucial, so please continue to let us know what you think — the sooner we hear from you, the more of your feedback we can integrate. When you find issues, please report them here.

Source: Android Developers Blog

Handling Nullability in Android 11 and Beyond

Posted by David Winer, Kotlin Product Manager

Last May at Google I/O, we announced that Android was going Kotlin first, and now over 60% of the top 1000 Android apps use Kotlin. One feature we love about Kotlin is that nullability is baked into its type system — when declaring a reference, you say upfront whether it can hold null values. In this post, we’ll look at how the Android 11 SDK does more to expose nullability information in its APIs and show how you can prepare your Kotlin code for it.

How does nullability in Kotlin work?

When writing code in Kotlin, you can use the question mark operator to indicate nullability:

KOTLIN

var x: Int = 1
x = null // compilation error

var y: Int? = 1
y = null // okay

This aspect of Kotlin makes your code safer — if you later call a method or try to access a property on a non-null variable like x, you know you’re not risking a null pointer exception. We hear over and over again that this feature of Kotlin gives developers more peace of mind and leads to higher quality apps for end users.

How does nullability work with the Java programming language?

Not all of your (or Android’s) APIs are written in Kotlin. Fortunately, the Kotlin compiler recognizes annotations on Java programming languages methods that indicate whether they produce nullable or non-nullable values. For example:

JAVA

public @Nullable String getCurrentName() {
   return currentName;
}

The @Nullable annotation ensures that when using the result of getCurrentName in a Kotlin file, you can’t dereference it without a null check. If you try, Android Studio will notify you of an error, and the Kotlin compiler will throw an error in your build. The opposite is true of @NonNull — it tells the Kotlin compiler to treat the method result as a non-null type, forbidding you from assigning that result to null later in your program.

The Kotlin compiler also recognizes two similar annotations, @RecentlyNullable and @RecentlyNonNull, which are the exact same as @Nullable and @NonNull, only they generate warnings instead of errors¹.

Nullability in Android 11

Last month, we released the Android 11 Developer Preview, which allows you to test out the new Android 11 SDK. We upgraded a number of annotations in the SDK from @RecentlyNullable and @RecentlyNonNull to @Nullable and @NonNull (warnings to errors) and continued to annotate the SDK with more @RecentlyNullable and @RecentlyNonNull annotations on methods that didn’t have nullability information before.

What’s next

If you are writing in Kotlin, when upgrading from the Android 10 to the Android 11 SDK, you may notice that there are some new compiler warnings and that previous warnings may have been upgraded to errors. This is intended and a feature of the Kotlin compiler — these warnings tell you that you may be writing code that crashes your app at runtime (a risk you would miss entirely if you weren’t writing in Kotlin). As you encounter these warnings and errors, you can handle them by adding null checks to your code.

As we continue to make headway annotating the Android SDK, we’ll follow this same pattern — @RecentlyNullable and @RecentlyNonNull for one numbered release (e.g., Android 10), and then upgrade to @Nullable and @NonNull in the next release (e.g., Android 11). This practice will give you at least a full release cycle to update your Kotlin code and ensure you’re writing high-quality, robust code.

1. Due to rules regarding handling of annotations in Kotlin, there is currently a small set of cases where the compiler will throw an error for @Nullable references but not for @RecentlyNullable references.

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

Source: Android Developers Blog

Join us for the digital Google for Games Developer Summit

Posted by the Google for Games Team GDC banner

Last month, Game Developers Conference (GDC) organizers made the difficult decision to postpone the conference. We understand this decision, as we have to prioritize the health and safety of our community. GDC is one of our most anticipated times of the year to connect with the gaming industry. Though we won’t be bringing the news in-person this year, we’re hosting the Google for Games Developer Summit, a free, digital-only experience where developers can watch the announcements and session content that was planned for GDC.

Google for Games Developer Summit

The Developer Summit kicks off on March 23rd at 9:00AM PT with our broadcasted keynote. Immediately following, we’ll be releasing a full lineup of developer sessions with over 10 hours of content to help take your games to the next level.

Here are some types of sessions to expect:

Success stories from industry leaders on how they’ve conquered game testing, built backend infrastructure, and launched great games across all platforms.
New announcements like Android development and profiling tools that can help deploy large APKs to devices faster, fine tune graphic performance, and analyze device memory more effectively.
Updates on products like Game Servers (currently in alpha)—a fully managed offering of Agones, letting developers easily deploy and manage containerized game servers around the globe.

Support for the game developer community

We recognize every developer is impacted differently by this situation. We’re coordinating with the GDC Relief Fund to sponsor and assist developers who’ve invested in this moment to further grow their games.

We also understand many developers were looking forward to sharing their content with peers. To help with this, developers can use YouTube to stream events from small to large using tools like Live Streaming and Premieres.

We can’t wait to share what we have in store for gaming. Discover the solutions our teams have been building to support the success of this community for years to come.

This article was cross-posted from the Google Developer Blog. Google Play will be participating in the Google for Games Developer Summit on March 23rd at 9:00AM PT to share how we're making Google Play even more powerful for game developers!

Source: Android Developers Blog

Android Platform Codelab Kickstarts OS Development

Posted by Clay Murphy, Technical Writer

The Android Platform Codelab has been published to take developers from bare metal to a (virtual) device under test in a single page. This document will help new Android operating system engineers quickly learn the tools and processes needed to establish a build environment, sync the repository, build a virtual device image, and load that image onto an Android virtual device (AVD), allowing quick iteration of platform changes.

The codelab walks through:

Environment setup
Downloading of code
Creating a Cuttlefish Android Virtual Device (AVD) image
Building the OS
Using Acloud to set up and render the Cuttlefish AVD
Creating and testing changes
Uploading, reviewing, and reverting those modifications

If you encounter errors during this codelab, please report them using the Site feedback link on the bottom of any page. Send questions to the android-building group.

Source: Android Developers Blog

Unveiling expert insights in our new podcast series: Apps, Games, & Insights

Posted by Lily Sheringham, Global Marketing, Platforms & Ecosystems

This is a cross-post from The Google Keyword blog.

Today we’re launching the Apps, Games, & Insights podcast series, bringing together insights, stories, and learnings from industry experts, on some of today's hottest topics surrounding mobile, apps and games businesses, and the wider industry.

Listen to the podcast here!

The series has eight episodes which aim to challenge, provoke thought, and enlighten listeners - from designers and developers, through to product managers and marketers, and those interested in the apps and games industry.

The podcast is hosted by Googlers Tamzin Taylor, who heads up Apps & Games Business Development for Google Play in Western Europe, and Dirk Primbs, who leads the Ecosystem Developer Relations team in EMEA. Together, they have many years of experience working with partners to assist with Android development, mobile, app, game, and business growth. Every week they will be joined by different guests for each of the episodes.

Sneak peek at what’s coming up

Kicking off the series are Judy Chen and Sarah Fuchs from Crowdstar, the developers of Covet Fashion and Design Home. They join us for episode 1 to discuss how to build a long-term games business by taking a holistic approach to the game, its players, and the people who create the game.

Ever wonder if it's worth selling your app or game business, and if so how to approach it? It's not all about pocketing the cash and walking away. For episode 2, game mergers and acquisitions expert Chris Petrovic from Zynga will talk about how acquisition can free developers to focus on what they love: creating great apps and games.

The popularity of subscriptions continues to grow, with developers who used subscriptions earning 4X more in 2018, than in 2016. Holly Ackerman and David Berlin, from the sports streaming platform DAZN, join us for episode 3 to provide some fascinating insights into how they have grown their subscription business in this industry.

Whether you are a startup in search of funding or an established business looking to accelerate your investment, venture capital can often be a good source of funds. In episode 4, venture capital expert Matteo Vallone from Cherry Ventures offers insights into the investment process and how to maximize your appeal to investors.

For episode 5, we have what is possibly one of the biggest topics in mobile and throughout the tech industry: privacy. Bruce Gustafson, CEO of Developers Alliance brings us up to speed on trust and safety, platform value, respecting the user, and ultimately building privacy friendly apps and games.

Successful game developers put players front and center of everything they do. When over 270 million people have played your games, you must be doing something right. Ben Clarke, Senior Global Marketing Director at Jagex, joins us for episode 6 to discuss some of the innovative approaches to player engagement and retention taken in their RuneScape games.

Figuring out how to make your app or game accessible to all can often be a challenge, sometimes both from an organizational and technical perspective. However, many developers have made accessibility a core part of their app development process and company culture. For episode 7, we’re joined by Ceri Lindsay and Rosalind Whittam from the BBC to discover how they address accessibility.

Today, Android is not just about smartphones, Android apps and games can run on a range of devices with larger screens, such as Chromebooks. At the same time, mature mobile game franchises are looking for opportunities beyond mobile. In our final episode 8, we’ll be joined by Maximiliano Rodriguez of Gameloft to talk about the challenge of taking games to big screens and new platforms.

We hope you’ll join us over the next eight weeks to dive deeper and hear what our thought leader guests have to say on each topic.

How to stay tuned in

To listen to our first podcast and find out more about what’s coming, check out our new Apps, Games, & Insights podcast homepage.

Listen to our first episode here, or on Spotify, Apple Podcasts, Google Play Music, Google Podcasts, Deezer, iHeartRadio, and also on LibSyn. Keep an eye out on @GooglePlayDev and @AndroidDev on Twitter where we will be announcing the launch of the new episodes each week.

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Source: Android Developers Blog

Update on Google at GDC 2020

Posted by the Google for Games Team

Last Friday, GDC 2020 organizers made the difficult decision to postpone the conference. We understand this decision, as we have to prioritize the health and safety of our community.

Every year, we look forward to the Game Developers Conference and surrounding events because it gives our teams a chance to connect with game developers, partners, and friends in the industry.

Although we won’t be connecting in-person this year, we’re still excited to share the latest announcements from Google with everyone through our digital experience. We'll be sharing plans for our digital experience in the coming days.

Thank you to all who keep this community thriving and check back soon at g.co/gdc2020 for more details.

Source: Android Developers Blog

Data Encryption on Android with Jetpack Security

Posted by Jon Markoff, Staff Developer Advocate, Android Security

Have you ever tried to encrypt data in your app? As a developer, you want to keep data safe, and in the hands of the party intended to use. But if you’re like most Android developers, you don’t have a dedicated security team to help encrypt your app’s data properly. By searching the web to learn how to encrypt data, you might get answers that are several years out of date and provide incorrect examples.

The Jetpack Security (JetSec) crypto library provides abstractions for encrypting Files and SharedPreferences objects. The library promotes the use of the AndroidKeyStore while using safe and well-known cryptographic primitives. Using EncryptedFile and EncryptedSharedPreferences allows you to locally protect files that may contain sensitive data, API keys, OAuth tokens, and other types of secrets.

Why would you want to encrypt data in your app? Doesn’t Android, since 5.0, encrypt the contents of the user's data partition by default? It certainly does, but there are some use cases where you may want an extra level of protection. If your app uses shared storage, you should encrypt the data. In the app home directory, your app should encrypt data if your app handles sensitive information including but not limited to personally identifiable information (PII), health records, financial details, or enterprise data. When possible, we recommend that you tie this information to biometrics for an extra level of protection.

Jetpack Security is based on Tink, an open-source, cross-platform security project from Google. Tink might be appropriate if you need general encryption, hybrid encryption, or something similar. Jetpack Security data structures are fully compatible with Tink.

Key Generation

Before we jump into encrypting your data, it’s important to understand how your encryption keys will be kept safe. Jetpack Security uses a master key, which encrypts all subkeys that are used for each cryptographic operation. JetSec provides a recommended default master key in the MasterKeys class. This class uses a basic AES256-GCM key which is generated and stored in the AndroidKeyStore. The AndroidKeyStore is a container which stores cryptographic keys in the TEE or StrongBox, making them hard to extract. Subkeys are stored in a configurable SharedPreferences object.

Primarily, we use the AES256_GCM_SPEC specification in Jetpack Security, which is recommended for general use cases. AES256-GCM is symmetric and generally fast on modern devices.

val keyAlias = MasterKeys.getOrCreate(MasterKeys.AES256_GCM_SPEC)

For apps that require more configuration, or handle very sensitive data, it’s recommended to build your KeyGenParameterSpec, choosing options that make sense for your use. Time-bound keys with BiometricPrompt can provide an extra level of protection against rooted or compromised devices.

Important options:

userAuthenticationRequired() and userAuthenticationValiditySeconds() can be used to create a time-bound key. Time-bound keys require authorization using BiometricPrompt for both encryption and decryption of symmetric keys.
unlockedDeviceRequired() sets a flag that helps ensure key access cannot happen if the device is not unlocked. This flag is available on Android Pie and higher.
Use setIsStrongBoxBacked(), to run crypto operations on a stronger separate chip. This has a slight performance impact, but is more secure. It’s available on some devices that run Android Pie or higher.

Note: If your app needs to encrypt data in the background, you should not use time-bound keys or require that the device is unlocked, as you will not be able to accomplish this without a user present.

// Custom Advanced Master Key
val advancedSpec = KeyGenParameterSpec.Builder(
    "master_key",
    KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT
).apply {
    setBlockModes(KeyProperties.BLOCK_MODE_GCM)
    setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
    setKeySize(256)
    setUserAuthenticationRequired(true)
    setUserAuthenticationValidityDurationSeconds(15) // must be larger than 0
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
        setUnlockedDeviceRequired(true)
        setIsStrongBoxBacked(true)
    }
}.build()

val advancedKeyAlias = MasterKeys.getOrCreate(advancedSpec)

Unlocking time-bound keys

You must use BiometricPrompt to authorize the device if your key was created with the following options:

userAuthenticationRequired is true
userAuthenticationValiditySeconds > 0

After the user authenticates, the keys are unlocked for the amount of time set in the validity seconds field. The AndroidKeystore does not have an API to query key settings, so your app must keep track of these settings. You should build your BiometricPrompt instance in the onCreate() method of the activity where you present the dialog to the user.

BiometricPrompt code to unlock time-bound keys

// Activity.onCreate

val promptInfo = PromptInfo.Builder()
    .setTitle("Unlock?")
    .setDescription("Would you like to unlock this key?")
    .setDeviceCredentialAllowed(true)
    .build()

val biometricPrompt = BiometricPrompt(
    this, // Activity
    ContextCompat.getMainExecutor(this),
    authenticationCallback
)

private val authenticationCallback = object : AuthenticationCallback() {
        override fun onAuthenticationSucceeded(
            result: AuthenticationResult
        ) {
            super.onAuthenticationSucceeded(result)
            // Unlocked -- do work here.
        }
        override fun onAuthenticationError(
            errorCode: Int, errString: CharSequence
        ) {
            super.onAuthenticationError(errorCode, errString)
            // Handle error.
        }
    }

To use:
biometricPrompt.authenticate(promptInfo)

Encrypt Files

Jetpack Security includes an EncryptedFile class, which removes the challenges of encrypting file data. Similar to File, EncryptedFile provides a FileInputStream object for reading and a FileOutputStream object for writing. Files are encrypted using Streaming AEAD, which follows the OAE2 definition. The data is divided into chunks and encrypted using AES256-GCM in such a way that it's not possible to reorder.

val secretFile = File(filesDir, "super_secret")
val encryptedFile = EncryptedFile.Builder(
    secretFile,
    applicationContext,
    advancedKeyAlias,
    FileEncryptionScheme.AES256_GCM_HKDF_4KB)
    .setKeysetAlias("file_key") // optional
    .setKeysetPrefName("secret_shared_prefs") // optional
    .build()

encryptedFile.openFileOutput().use { outputStream ->
    // Write data to your encrypted file
}

encryptedFile.openFileInput().use { inputStream ->
    // Read data from your encrypted file
}

Encrypt SharedPreferences

If your application needs to save Key-value pairs - such as API keys - JetSec provides the EncryptedSharedPreferences class, which uses the same SharedPreferences interface that you’re used to.

Both keys and values are encrypted. Keys are encrypted using AES256-SIV-CMAC, which provides a deterministic cipher text; values are encrypted with AES256-GCM and are bound to the encrypted key. This scheme allows the key data to be encrypted safely, while still allowing lookups.

EncryptedSharedPreferences.create(
    "my_secret_prefs",
    advancedKeyAlias,
    applicationContext,
    PrefKeyEncryptionScheme.AES256_SIV,
    PrefValueEncryptionScheme.AES256_GCM
).edit {
    // Update secret values
}

More Resources

FileLocker is a sample app on the Android Security GitHub samples page. It’s a great example of how to use File encryption using Jetpack Security.

Happy Encrypting!