Category Archives: Android Developers Blog

An Open Handset Alliance Project

Google Play security metadata and offline app distribution

Posted by James Bender, Product Manager, Google Play

In December last year we announced that we would be making updates to app security to help verify product authenticity from Google Play. We are now adding a small amount of security metadata on top of APKs to verify that the APK was distributed by Google Play.

One of the reasons we're doing this is to help developers reach a wider audience, particularly in countries where peer-to-peer app sharing is common because of costly data plans and limited connectivity.

In the future, for apps obtained through Play-approved distribution channels, we'll be able to determine app authenticity while a device is offline, add those shared apps to a user's Play Library, and manage app updates when the device comes back online. This will give people more confidence when using Play-approved peer-to-peer sharing apps.

This also benefits you as a developer as it provides a Play-authorized offline distribution channel and, since the peer-to-peer shared app is added to your user's Play library, your app will now be eligible for app updates from Play.

No action is needed by developers or by those who use your app or game. We're adjusting Google Play's maximum APK size to take into account the small metadata addition, which is inserted into the APK Signing Block. In addition to improving the integrity of Google Play's mobile app ecosystem, this metadata will also present new distribution opportunities for developers and help more people keep their apps up to date.

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#IMakeApps – Celebrating app makers worldwide

Posted by Patricia Correa, Director, Developer Marketing, Platforms & Ecosystems

The Android developer ecosystem is made up of exceptional individuals with different backgrounds, interests, and dreams. To celebrate the people who make up our community, starting today, and over the coming months, we'll be meeting with developers, founders, product managers, designers, and others from around the world to hear more about their passions and discover what they do when they step away from their computers.

Watch stories featuring adventurer Niek Bokkers from Polarsteps (Netherlands), artist Faith Ringgold from Quiltuduko (USA) and chair restorer Hans Jørgen Wiberg from Be My Eyes (Denmark). You can also read more about them and their apps on g.co/play/imakeapps.

Share your story

We'd love to hear from you too. Use the hashtag #IMakeApps on your social channels, sharing the app or game you work on, your role in its creation, and an image that best depicts who you are outside of work. We will regularly select and share some of our favorites on our channels.

If you also want to get featured in an upcoming #IMakeApps film, tell us more about yourself and your app or game, by completing this self-nomination form.

Stay tuned for more #IMakeApps stories by following us on Twitter, YouTube and LinkedIn.

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An Update on non-SDK restrictions in Android P

Posted by David Brazdil and Nicolas Geoffray, Software Engineers

In Android, we care immensely about providing the best experience to our users and our developers. With each OS release, new features enable you to provide amazing experiences for users; however, we noticed that some app developers have been using non-SDK interfaces, which leads to increased crashes for users and emergency rollouts for developers. We want to do better and need your help to ensure that Android is stable with each new OS.

Three months ago, we announced our plans to start restricting the usage of non-SDK interfaces in Android P. We know these restrictions can impact your release workflow, and we want to make sure you have the tools to detect usage of non-SDK interfaces, as well as time in your planning for adjusting to the new policies and for giving us feedback.

In the Developer Preview and Beta 1, we have provided ways for you to see the impact of these restrictions on your app. In the Developer Preview, use of restricted APIs show up in logs and toast messages, and in Beta 1, we provided a StrictMode policy that allows you to programmatically find these restrictions and do your own logging. For example:

We understand there can be multiple reasons apps want to use non-SDK interfaces, and ensuring your app will continue to work in Android P is important to us. Many of you have explained your use cases through our issue tracker (thank you!), and for most of these requests, we have lifted the restrictions on specific non-SDK interfaces for Android P by adding them to the greylist. In addition, our team has conducted static analysis on millions of apps and processed thousands of automated reports from internal and external beta testers. Through this analysis, we have identified additional non-SDK interfaces that apps rely on and added them to the greylist. For everything on the greylist, we will be investigating public SDK alternatives for future releases. However, it's possible we may have missed some non-SDK interface uses, so we have made the majority of them available for apps whose target SDK is Android Oreo or below.

In summary, apps running on Android P will be subject to restricted usage of non-SDK interfaces. If you are targeting Android P, the greylist shows the non-SDK interfaces that will still be available, while all other non-SDK interfaces will not be accessible. If you are targeting Android Oreo or below, most restrictions will not apply, but you will get logcat warnings if you are accessing non-SDK interfaces that are not in the greylist (note that users don't see such warnings).

Try out our new Beta 2 release and use StrictMode to detect your non-SDK interfaces usage. You should expect Beta 2 to closely match what the final release will implement for restricting non-SDK interface usages. Also, please take a look at our new FAQ, which we hope will answer any questions you have around the feature. If not, let us know!

Wear OS developer preview reenabling alarms and jobs for background apps

Posted by Hoi Lam, Lead Developer Advocate, Wear OS by Google

From the outset of the Wear OS by Google developer preview, battery life has been a major focus area. When we talked to the developer community, the update that attracted the most feedback was the disabling of alarms and jobs for background apps. After listening to developer feedback and reviewing the battery statistics, we are reversing this change. This should be reflected in all connected Wear OS preview devices, so there is no need to reflash your device.

App Standby Buckets

The decision came as we reviewed the feedback and saw that a strict on/off setting prevents reasonable usage and promotes anti-patterns. Going forward, we plan to leverage the App Standby Buckets feature in Android P to fine-tune a suitable setting for Wear OS devices. The exact setting for alarms and jobs for background apps is still being iterated on. Developers are advised to follow the best practices to make sure their apps behave well, whichever bucket the apps are in.

Input and data privacy in background apps

Another area that developers should pay attention to is the strengthening of input and data privacy for background apps in Android P. Depending on an app's requirements, developers may need to use a foreground service to enable access to the device sensor throughout the day.

Please give us your feedback

We expect to provide more updates to this preview before the final production release. Please submit any bugs you find via the Wear OS by Google issue tracker. The earlier you submit them, the higher the likelihood that we can include the fixes in the final release.

Android P Beta 2 and final APIs!

Posted By Dave Burke, VP of Engineering

Android P Logo

Four weeks ago at Google I/O we released the first beta version of Android P, putting AI at the core of the operating system and focusing on intelligent and simple experiences.

We talked about some of Android's newest features in the keynotes and went deep on the developer APIs during the breakouts. If you missed the livestream, make sure to check out the full playlist of Android talks.

Today we're releasing Android P Beta 2, an update that includes the final Android P APIs, the latest system images, and updated developer tools to help you get ready for the consumer release coming later in the summer.

You can get Android P Beta 2 on Pixel devices by enrolling here. If you're already enrolled and received the Android P Beta 1 on your Pixel device, you'll automatically get the update to Beta 2. Partners that are participating in the Android P Beta program will be updating their devices over the coming weeks.

Enhance your app with Android P features and APIs

Android P Beta 2 is the latest update of our upcoming Android P platform and includes the final APIs (API level 28) as well as the official SDK. You can get started building with the Android P features and APIs today. Here are a few we want you to try -- head over to the features overview for more.

Machine learning at the core

Adaptive battery image

We partnered with DeepMind on a feature we call Adaptive Battery that uses machine learning to prioritize system resources for the apps the user cares about most. If your app is optimized for Doze, App Standby, and Background Limits, Adaptive Battery should work well for you right out of the box. Make sure to check out the details in the power documentation to see how it works and where the impacts could be, and test your apps to make sure they are ready.

App Actions is a new way to help you raise the visibility of your app and help drive engagement. Actions take advantage of machine learning on Android to surface your app to the user at just the right time, based on your app's semantic intents and the user's context. Actions work on Android P and earlier versions of the platform and they'll be available soon for you to start using. Sign up here to be notified when Actions are available.

Slices are a new way to surface rich, templated content in places like Google Search and Assistant. They're interactive, and through Android Jetpack they're compatible all the way back to KitKat. Check out the Getting Started guide to learn how to build with Slices -- you can use the SliceViewer tool to see how your Slices look. Over time we plan to expand the number of places that your Slices can appear, including remote display in other apps.

Simplicity, polish

Android P adds platform support for screens with display cutouts, and we've added new APIs to let you deliver a rich, edge-to-edge experience on the latest screens. Cutout support works seamlessly for apps, with the system managing status bar height to separate your content from the cutout. If you have immersive content, you can use the display cutout APIs to check the position and shape of the cutout and request full-screen layout around it.

All developers should check out the docs to learn how to manage the cutout area and avoid common compatibility issues that can affect apps. Make sure to test your app on a device that has a display cutout, such as one of the Android P Beta devices.

Immersive content display.

Apps with immersive content can display content fullscreen on devices with a display cutout.

If your app uses messaging notifications, take advantage of the changes in MessagingStyle that make notifications even more useful and actionable. You can now show conversations, attach photos and stickers, and even suggest smart replies. You'll soon be able to use ML Kit to generate smart reply suggestions your app.

MessagingStyle notifications MessagingStyle notifications

MessagingStyle notifications with conversations and smart replies [left], images and stickers [right].

Security

Verify purchase icon

With a range of biometric sensors in use for authentication, we've made the experience more consistent across sensor types and apps. Android P introduces a system-managed dialog to prompt the user for any supported type of biometric authentication. Apps no longer need to build their own dialog -- instead they use the BiometricPrompt API to show the standard system dialog. In addition to Fingerprint (including in-display sensors), the API supports Face and Iris authentication.

If your app is drawing its own fingerprint auth dialogs, you should switch to using the BiometricPrompt API as soon as possible.

More

If your app uses the device camera, try the new multi-camera APIs that let you access streams simultaneously from two or more physical cameras. On devices with dual cameras, you can create innovative features not possible with a single camera -- such as seamless zoom, bokeh, and stereo vision. You can get started today using any of the Android P Beta devices that offers a dual camera.

Audio apps can use the Dynamics Processing API for access to a multi-stage, multi-band dynamics processing effect to modify the audio coming out of Android devices and optimize it according to the preferences of the listener or the ambient conditions. Dynamics Processing API Take a look at the Android P features overview for a complete list of the new features and APIs.

Get started in a few simple steps

Android Virtual Device

First, make your app compatible and give your users a seamless transition to Android P. Just install your current app from Google Play on a Android P Beta device or emulator and test -- the app should run and look great, and handle Android P behavior change for all apps properly. After you've made any necessary updates, we recommend publishing to Google Play right away without changing the app's platform targeting.

If you don't have a supported device, remember that you can set up an Android Virtual Device on the Android Emulator as your test environment instead. If you haven't tried the emulator recently, you'll find that it's incredibly fast, boots in under 6 seconds, and even lets you model next-gen screens -- such as long screens and screens with display cutout.

Next, update your app's targetSdkVersion to 28 as soon as possible, so Android P users of your app can benefit from the platform's latest security, performance, and stability features. If your app is already targeting API 26+ in line with Google Play's upcoming policies, then changing to target 28 should be a small jump.

It's also important to test your apps for uses of non-SDK interfaces and reduce your reliance on them. As noted previously, in Android P we're starting a gradual process to restrict access to selected non-SDK interfaces. Watch for logcat warnings that highlight direct uses of restricted non-SDK interfaces and try the new StrictMode method detectNonSdkApiUsage() to catch accesses programmatically. Where possible, you should move to using public equivalents from the Android SDK or NDK. If there's no public API that meets your use-case, please let us know.

When you're ready, dive into Android P and learn about the new features and APIs to extend your apps. To build with the new APIs, just download the official API 28 SDK and tools into Android Studio 3.1, or use the latest version of Android Studio 3.2. Then update your project's compileSdkVersion and targetSdkVersion to API 28.

Visit the Developer Preview site for details and documentation. Also check out this video and the Google I/O Android playlist for more on what's new in Android P for developers.

Publish to Google Play alpha, beta, or production channels

Starting today you can publish your APK updates that are compiled against, or optionally targeting, API 28. Publishing an update to Google Play during the preview lets you push updates to users to test compatibility on existing devices, including devices running Android P Beta 2.

To make sure that your updated app runs well on Android P as well as older versions, a common strategy is to use Google Play's beta testing feature to get early feedback from a small group of users -- including Android P Beta 2 users — and then do a staged rollout to production.

How to get Android P Beta 2

For Pixel devices, you can enroll your device in the Android Beta program and you'll automatically receive the update to Android P Beta 2 over-the-air. If you're already enrolled and received Beta 1, watch for the update coming your way soon. Partners that are participating in the Android P Beta program will be updating their devices over the coming weeks.

You can see the full list of supported partner and Pixel devices at android.com/beta. For each device you'll find specs and links to the manufacturer's dedicated site for downloads, support, and to report issues.

Thanks for all of your feedback so far. Please continue to share feedback or requests as we work towards the consumer release later this summer. Feel free to use our hotlists for platform issues, app compatibility issues, and third-party SDK issues.

We're looking forward to seeing your apps on Android P!

Project Capillary: End-to-end encryption for push messaging, simplified

Posted by Giles Hogben, Privacy Engineer and Milinda Perera, Software Engineer

Developers already use HTTPS to communicate with Firebase Cloud Messaging (FCM). The channel between FCM server endpoint and the device is encrypted with SSL over TCP. However, messages are not encrypted end-to-end (E2E) between the developer server and the user device unless developers take special measures.

To this end, we advise developers to use keys generated on the user device to encrypt push messages end-to-end. But implementing such E2E encryption has historically required significant technical knowledge and effort. That is why we are excited to announce the Capillary open source library which greatly simplifies the implementation of E2E-encryption for push messages between developer servers and users' Android devices.

We also added functionality for sending messages that can only be decrypted on devices that are unlocked. This includes support for decrypting messages on devices using File-Based Encryption (FBE): encrypted messages are cached in Device Encrypted (DE) storage and message decryption keys are stored in Android Keystore, requiring user authentication. This allows developers to specify messages with sensitive content, that remain encrypted in cached form until the user has unlocked and decrypted their device.

The library handles:

  • Crypto functionality and key management across all versions of Android back to KitKat (API level 19).
  • Key generation and registration workflows.
  • Message encryption (on the server) and decryption (on the client).
  • Integrity protection to prevent message modification.
  • Caching of messages received in unauthenticated contexts to be decrypted and displayed upon device unlock.
  • Edge-cases, such as users adding/resetting device lock after installing the app, users resetting app storage, etc.

The library supports both RSA encryption with ECDSA authentication and Web Push encryption, allowing developers to re-use existing server-side code developed for sending E2E-encrypted Web Push messages to browser-based clients.

Along with the library, we are also publishing a demo app (at last, the Google privacy team has its own messaging app!) that uses the library to send E2E-encrypted FCM payloads from a gRPC-based server implementation.

What it's not

  • The open source library and demo app are not designed to support peer-to-peer messaging and key exchange. They are designed for developers to send E2E-encrypted push messages from a server to one or more devices. You can protect messages between the developer's server and the destination device, but not directly between devices.
  • It is not a comprehensive server-side solution. While core crypto functionality is provided, developers will need to adapt parts of the sample server-side code that are specific to their architecture (for example, message composition, database storage for public keys, etc.)

You can find more technical details describing how we've architected and implemented the library and demo here.

.app is open for general registration

Posted by Christina Chiou Yeh, Google Registry

On May 1 we announced .app, the newest top-level domain (TLD) from Google Registry. It's now open for general registration so you can register your desired .app name right now. Check out what some of our early adopters are already doing on .app around the globe.

We begin our journey with sitata.app, which provides real-time travel information about events like protests or transit strikes. Looks all clear, so our first stop is the Caribbean, where we use thelocal.app and start exploring. After getting some sun, we fly to the Netherlands, where we're feeling hungry. Luckily, picnic.app delivers groceries, right to our hotel. With our bellies full, it's time to head to India, where we use myra.app to order the medicine, hygiene, and baby products that we forgot to pack. Did we mention this was a business trip? Good thing lola.app helped make such a complex trip stress free.

We hope these apps inspire you to also find your home on .app! Visit get.app to choose a registrar partner to register your domain.

Insider Attack Resistance

Posted by Shawn Willden, Staff Software Engineer

Our smart devices, such as mobile phones and tablets, contain a wealth of personal information that needs to be kept safe. Google is constantly trying to find new and better ways to protect that valuable information on Android devices. From partnering with external researchers to find and fix vulnerabilities, to adding new features to the Android platform, we work to make each release and new device safer than the last. This post talks about Google's strategy for making the encryption on Google Pixel 2 devices resistant to various levels of attack—from platform, to hardware, all the way to the people who create the signing keys for Pixel devices.

We encrypt all user data on Google Pixel devices and protect the encryption keys in secure hardware. The secure hardware runs highly secure firmware that is responsible for checking the user's password. If the password is entered incorrectly, the firmware refuses to decrypt the device. This firmware also limits the rate at which passwords can be checked, making it harder for attackers to use a brute force attack.

To prevent attackers from replacing our firmware with a malicious version, we apply digital signatures. There are two ways for an attacker to defeat the signature checks and install a malicious replacement for firmware: find and exploit vulnerabilities in the signature-checking process or gain access to the signing key and get their malicious version signed so the device will accept it as a legitimate update. The signature-checking software is tiny, isolated, and vetted with extreme thoroughness. Defeating it is hard. The signing keys, however, must exist somewhere, and there must be people who have access to them.

In the past, device makers have focused on safeguarding these keys by storing the keys in secure locations and severely restricting the number of people who have access to them. That's good, but it leaves those people open to attack by coercion or social engineering. That's risky for the employees personally, and we believe it creates too much risk for user data.

To mitigate these risks, Google Pixel 2 devices implement insider attack resistance in the tamper-resistant hardware security module that guards the encryption keys for user data. This helps prevent an attacker who manages to produce properly signed malicious firmware from installing it on the security module in a lost or stolen device without the user's cooperation. Specifically, it is not possible to upgrade the firmware that checks the user's password unless you present the correct user password. There is a way to "force" an upgrade, for example when a returned device is refurbished for resale, but forcing it wipes the secrets used to decrypt the user's data, effectively destroying it.

The Android security team believes that insider attack resistance is an important element of a complete strategy for protecting user data. The Google Pixel 2 demonstrated that it's possible to protect users even against the most highly-privileged insiders. We recommend that all mobile device makers do the same. For help, device makers working to implement insider attack resistance can reach out to the Android security team through their Google contact.

Acknowledgements: This post was developed in joint collaboration with Paul Crowley, Senior Software Engineer

Insider Attack Resistance

Posted by Shawn Willden, Staff Software Engineer

Our smart devices, such as mobile phones and tablets, contain a wealth of personal information that needs to be kept safe. Google is constantly trying to find new and better ways to protect that valuable information on Android devices. From partnering with external researchers to find and fix vulnerabilities, to adding new features to the Android platform, we work to make each release and new device safer than the last. This post talks about Google's strategy for making the encryption on Google Pixel 2 devices resistant to various levels of attack—from platform, to hardware, all the way to the people who create the signing keys for Pixel devices.

We encrypt all user data on Google Pixel devices and protect the encryption keys in secure hardware. The secure hardware runs highly secure firmware that is responsible for checking the user's password. If the password is entered incorrectly, the firmware refuses to decrypt the device. This firmware also limits the rate at which passwords can be checked, making it harder for attackers to use a brute force attack.

To prevent attackers from replacing our firmware with a malicious version, we apply digital signatures. There are two ways for an attacker to defeat the signature checks and install a malicious replacement for firmware: find and exploit vulnerabilities in the signature-checking process or gain access to the signing key and get their malicious version signed so the device will accept it as a legitimate update. The signature-checking software is tiny, isolated, and vetted with extreme thoroughness. Defeating it is hard. The signing keys, however, must exist somewhere, and there must be people who have access to them.

In the past, device makers have focused on safeguarding these keys by storing the keys in secure locations and severely restricting the number of people who have access to them. That's good, but it leaves those people open to attack by coercion or social engineering. That's risky for the employees personally, and we believe it creates too much risk for user data.

To mitigate these risks, Google Pixel 2 devices implement insider attack resistance in the tamper-resistant hardware security module that guards the encryption keys for user data. This helps prevent an attacker who manages to produce properly signed malicious firmware from installing it on the security module in a lost or stolen device without the user's cooperation. Specifically, it is not possible to upgrade the firmware that checks the user's password unless you present the correct user password. There is a way to "force" an upgrade, for example when a returned device is refurbished for resale, but forcing it wipes the secrets used to decrypt the user's data, effectively destroying it.

The Android security team believes that insider attack resistance is an important element of a complete strategy for protecting user data. The Google Pixel 2 demonstrated that it's possible to protect users even against the most highly-privileged insiders. We recommend that all mobile device makers do the same. For help, device makers working to implement insider attack resistance can reach out to the Android security team through their Google contact.

Acknowledgements: This post was developed in joint collaboration with Paul Crowley, Senior Software Engineer

All the (Android) Things at Google I/O

Melissa Daniels, Program Manager for Android Things

Android Things enables you to build and maintain IoT devices at scale. We recently released Android Things 1.0 with long-term support for production devices, so you can easily take an IoT device from prototype to commercial product.

We packed Google I/O this year with Android Things content to inspire and empower the developer community, from talks and codelabs to interactive demos and a scavenger hunt. Here's a closer look at the fun stuff we had on display that you won't see on the shelves of retail stores.

Demos

We introduced a handful of new interactive Android Things demos across I/O, showcasing the AI and ML capabilities of the platform, so if you didn't get an opportunity to attend this year, here's a few of our favorites-- perfect for exploring from wherever you are in the world!

Smart Flowers: Flos Mobilis

What do you get when you combine machine learning, Android Things and robotics? Flos Mobilis, a continuum robot where each flower is backed by an i.MX7D development board and a camera to run an embedded neural net model that controls the motion of the flower. This is all done offline with no data stored or transmitted.

Smart Flowers: Flos Affectus

What if a robot could respond to the way you feel? Flos Affectus is a cluster of robotic flowers that "bloom" and "un-bloom" depending on the expression detected on the user's face. The 4 broad expressions Flos Affectus is trained to detect are: happy, sad, angry, surprised. Using a camera embedded in the head of the alpha flower, the flower cluster is able to detect the user's face and infer the facial emotion. The flower cluster runs offline with no data stored or transmitted and demonstrates movement capabilities and on-device machine learning models.

Rosie the Android

Initially designed by a team of Google engineers for the annual Grace Hopper conference, Rosie the Android is a 5 foot selfie-taking Android, complete with machine-learning capabilities. Inspired by Rosie the Riveter, she's a fully controllable robot that can take photos, respond to commands, wheel around and interact with those around her.

Did you take a selfie with Rosie at I/O? Redeem your unique access code at g.co/rosie

Smart Projector

Smart Projector is built on Lantern, an Android Things project exploring the relationship between surfaces and content — augmenting real-world objects and environments with glanceable, meaningful data. It leverages the Google Experiments project known as Quick Draw, using the world's largest doodling data set that has been shared publicly to help with machine learning research.

To learn more about Lantern or to start building your own, start here.

3D Printer

This modified Printrbot Smalls 3D Printer uses a real-time subsystem that showcases the flexibility of Android Things-- a microcontroller does the low-latency motor control, while Android Things handles OpenGL rendering. By keeping most of the logic on a high-level platform like Android you make development and debugging much easier, thanks to Android's great tooling.

The future of 3D printing? Making real-time control as easy and portable as the rest of Android Things.

Codelabs

Phew! That was just the tip of the demo iceberg. With so many demos and so many ways to use Android Things, it's easy to start imagining all the things you can build! At I/O, we helped a lot of developers get started building their first Android Things device using the Android Things Starter Kit. We're making these codelabs available, so you can get to them whenever you need, or build your own.

Videos

Missed the I/O talks? Catch the recordings of each Android Things talk, so you can start, pause, and rewind at your own leisure. Or, just lean back and watch them all.

What's new in Android Things

Build effective OEM-level apps on Android Things

Build real consumer devices with Android Things

Electronic design for Android Things System on Modules

Women Techmakers panel: experiences developing on Android Things

Product design: how to build better products with Android Things

Device provisioning and authentication with Android Things

Update production devices in the field with the Android Things Console

Start building!

On top of all the resources we just mentioned, we have a corpus of information on our developer documentation, and our new community website where you can see more inspiring projects and even submit your own. So, what are you waiting for? Pick up an Android Things Starter Kit and start building something today!