Tag Archives: Android

Tools to help developers provide a positive user experience

Posted by Lisa Martinez, Head of Security & Privacy Business Development, Google Play and Andrew Ahn, Product Manager, Play and Android App Safety

Google helps protect billions of users every day through the use of a robust set of tools designed to keep users safe online. We’re proud to provide a wide range of these same resources to help developers build safe and successful apps. User participation increases when people have a safe and positive app engagement. We’d like to highlight a few of these free tools that developers can consider to help make user experiences safer for everyone.

Reducing toxic conversation with Perspective API

Perspective API, a free product offered by Jigsaw, uses machine learning to identify toxic language, like insults, profanity, or identity based attacks, making it easier to host healthier conversations in your apps. Perspective can be used to give feedback to commenters, help moderators more easily review comments, and keep conversations open online. Many online publishers and developers, such as the New York Times, El País, FACEIT, and Coral by VoxMedia have started to adopt this tool to promote constructive online dialogues. Learn how to get started here.

Increase child safety with Content Safety API

Google’s Content Safety API uses artificial intelligence to help developers better prioritize abuse material for review. We offer this service to NGOs and private companies to support their work protecting children. The API steps up the fight for child safety by prioritizing potentially illegal content for human review and helping reviewers find and report content faster. Quicker identification of new abuse images increases the likelihood that children being abused could be identified and protected from further abuse. Making review queues more efficient and less noisy also reduces the toll on human reviewers, who review images to confirm instances of abuse. Learn more about this on our Protecting Children site.

Prevent links to unsafe files and sites with the Safe Browsing API

Google Safe Browsing helps protect billions of devices every day by showing warnings to users when they attempt to navigate to dangerous sites or download dangerous files. Safe Browsing also notifies webmasters when their websites are compromised by malicious actors. Safe Browsing protections work across Google products and power safer browsing experiences across the Internet. Technical information on how to get started can be found here.

Thank you for continuing to partner with us to provide a positive experience for our shared users on Google Play.

Source: Android Developers Blog

Rust in the Android platform

Posted by Jeff Vander Stoep and Stephen Hines, Android Team

Correctness of code in the Android platform is a top priority for the security, stability, and quality of each Android release. Memory safety bugs in C and C++ continue to be the most-difficult-to-address source of incorrectness. We invest a great deal of effort and resources into detecting, fixing, and mitigating this class of bugs, and these efforts are effective in preventing a large number of bugs from making it into Android releases. Yet in spite of these efforts, memory safety bugs continue to be a top contributor of stability issues, and consistently represent ~70% of Android’s high severity security vulnerabilities.

In addition to ongoing and upcoming efforts to improve detection of memory bugs, we are ramping up efforts to prevent them in the first place. Memory-safe languages are the most cost-effective means for preventing memory bugs. In addition to memory-safe languages like Kotlin and Java, we’re excited to announce that the Android Open Source Project (AOSP) now supports the Rust programming language for developing the OS itself.

Systems programming

Managed languages like Java and Kotlin are the best option for Android app development. These languages are designed for ease of use, portability, and safety. The Android Runtime (ART) manages memory on behalf of the developer. The Android OS uses Java extensively, effectively protecting large portions of the Android platform from memory bugs. Unfortunately, for the lower layers of the OS, Java and Kotlin are not an option.

Lower levels of the OS require systems programming languages like C, C++, and Rust. These languages are designed with control and predictability as goals. They provide access to low level system resources and hardware. They are light on resources and have more predictable performance characteristics.

For C and C++, the developer is responsible for managing memory lifetime. Unfortunately, it's easy to make mistakes when doing this, especially in complex and multithreaded codebases.

Rust provides memory safety guarantees by using a combination of compile-time checks to enforce object lifetime/ownership and runtime checks to ensure that memory accesses are valid. This safety is achieved while providing equivalent performance to C and C++.

The limits of sandboxing

C and C++ languages don’t provide these same safety guarantees and require robust isolation. All Android processes are sandboxed and we follow the Rule of 2 to decide if functionality necessitates additional isolation and deprivileging. The Rule of 2 is simple: given three options, developers may only select two of the following three options.

For Android, this means that if code is written in C/C++ and parses untrustworthy input, it should be contained within a tightly constrained and unprivileged sandbox. While adherence to the Rule of 2 has been effective in reducing the severity and reachability of security vulnerabilities, it does come with limitations. Sandboxing is expensive: the new processes it requires consume additional overhead and introduce latency due to IPC and additional memory usage. Sandboxing doesn’t eliminate vulnerabilities from the code and its efficacy is reduced by high bug density, allowing attackers to chain multiple vulnerabilities together.

Memory-safe languages like Rust help us overcome these limitations in two ways:

Lowers the density of bugs within our code, which increases the effectiveness of our current sandboxing.
Reduces our sandboxing needs, allowing introduction of new features that are both safer and lighter on resources.

But what about all that existing C++?

Of course, introducing a new programming language does nothing to address bugs in our existing C/C++ code. Even if we redirected the efforts of every software engineer on the Android team, rewriting tens of millions of lines of code is simply not feasible.

The above analysis of the age of memory safety bugs in Android (measured from when they were first introduced) demonstrates why our memory-safe language efforts are best focused on new development and not on rewriting mature C/C++ code. Most of our memory bugs occur in new or recently modified code, with about 50% being less than a year old.

The comparative rarity of older memory bugs may come as a surprise to some, but we’ve found that old code is not where we most urgently need improvement. Software bugs are found and fixed over time, so we would expect the number of bugs in code that is being maintained but not actively developed to go down over time. Just as reducing the number and density of bugs improves the effectiveness of sandboxing, it also improves the effectiveness of bug detection.

Limitations of detection

Bug detection via robust testing, sanitization, and fuzzing is crucial for improving the quality and correctness of all software, including software written in Rust. A key limitation for the most effective memory safety detection techniques is that the erroneous state must actually be triggered in instrumented code in order to be detected. Even in code bases with excellent test/fuzz coverage, this results in a lot of bugs going undetected.

Another limitation is that bug detection is scaling faster than bug fixing. In some projects, bugs that are being detected are not always getting fixed. Bug fixing is a long and costly process.

Each of these steps is costly, and missing any one of them can result in the bug going unpatched for some or all users. For complex C/C++ code bases, often there are only a handful of people capable of developing and reviewing the fix, and even with a high amount of effort spent on fixing bugs, sometimes the fixes are incorrect.

Bug detection is most effective when bugs are relatively rare and dangerous bugs can be given the urgency and priority that they merit. Our ability to reap the benefits of improvements in bug detection require that we prioritize preventing the introduction of new bugs.

Prioritizing prevention

Rust modernizes a range of other language aspects, which results in improved correctness of code:

Memory safety - enforces memory safety through a combination of compiler and run-time checks.
Data concurrency - prevents data races. The ease with which this allows users to write efficient, thread-safe code has given rise to Rust’s Fearless Concurrency slogan.
More expressive type system - helps prevent logical programming bugs (e.g. newtype wrappers, enum variants with contents).
References and variables are immutable by default - assist the developer in following the security principle of least privilege, marking a reference or variable mutable only when they actually intend it to be so. While C++ has const, it tends to be used infrequently and inconsistently. In comparison, the Rust compiler assists in avoiding stray mutability annotations by offering warnings for mutable values which are never mutated.
Better error handling in standard libraries - wrap potentially failing calls in Result, which causes the compiler to require that users check for failures even for functions which do not return a needed value. This protects against bugs like the Rage Against the Cage vulnerability which resulted from an unhandled error. By making it easy to propagate errors via the ? operator and optimizing Result for low overhead, Rust encourages users to write their fallible functions in the same style and receive the same protection.
Initialization - requires that all variables be initialized before use. Uninitialized memory vulnerabilities have historically been the root cause of 3-5% of security vulnerabilities on Android. In Android 11, we started auto initializing memory in C/C++ to reduce this problem. However, initializing to zero is not always safe, particularly for things like return values, where this could become a new source of faulty error handling. Rust requires every variable be initialized to a legal member of its type before use, avoiding the issue of unintentionally initializing to an unsafe value. Similar to Clang for C/C++, the Rust compiler is aware of the initialization requirement, and avoids any potential performance overhead of double initialization.
Safer integer handling - Overflow sanitization is on for Rust debug builds by default, encouraging programmers to specify a wrapping_add if they truly intend a calculation to overflow or saturating_add if they don’t. We intend to enable overflow sanitization for all builds in Android. Further, all integer type conversions are explicit casts: developers can not accidentally cast during a function call when assigning to a variable or when attempting to do arithmetic with other types.

Where we go from here

Adding a new language to the Android platform is a large undertaking. There are toolchains and dependencies that need to be maintained, test infrastructure and tooling that must be updated, and developers that need to be trained. For the past 18 months we have been adding Rust support to the Android Open Source Project, and we have a few early adopter projects that we will be sharing in the coming months. Scaling this to more of the OS is a multi-year project. Stay tuned, we will be posting more updates on this blog.

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

Source: Google Online Security Blog

Start Your Engines: Launch New Android Auto Apps to Production!

Posted by Eric Bahna, Product Manager

In March, we published the Android for Cars App Library as part of Jetpack and most developers have already migrated their implementations to it! In addition to fantastic partner adoption, drivers have been enthusiastic about the new apps and our quality metrics have been positive.

Partner apps running on the Jetpack library (clockwise from upper left): T map, Chargepoint, Sygic, PlugShare, AmiGO, 2GIS, A Better Route Planner, and Flitsmeister

Today, we’re thrilled to announce that you can publish your Android Auto navigation, parking, and charging apps to production! We’ve been hard at work stabilizing the library, Android Auto, and the publishing process to reach this milestone. Publishing to production enables drivers to use your Android Auto app on their car screen without needing to sign up for a beta program. Here’s how:

Design your app with our developer guide.
Develop your app with the latest version of androidx.car.app (1.0.0-rc01 as of this writing).
Test your app with the desktop head unit and the new testing library.
Publish your app to the production track in the Play Console!

Thank you for your collaboration and feedback on the Android for Cars App Library 1.0! One of the most common requests from Android Auto users has been for more categories of apps. Our goal with the library is to enable you to easily bring your app to 500+ models of Android Auto-compatible vehicles while meeting our app quality guidelines. The library abstracts away the complexities of screen form factors and input modes so you can focus on what makes your app shine.

Enabling navigation, parking, and charging apps in production is both a big step and the start of a much longer journey. We’re excited to see what you build and look forward to working together to deliver awesome in-car experiences.

Source: Android Developers Blog

MAD Skills WorkManager : Wrap-Up

Posted by Caren Chang, Developer Relations Engineer

In case you missed it, we’ve just finished a MAD Skills series on WorkManager. We started by introducing WorkManager for those new to the library and then proceeded to talk more about advanced usages including how to test and debug your WorkManager code. The series ended with an episode on how to migrate your old code from GCMNetworkManager and FirebaseJobDispatcher to use WorkManager instead.

Here’s a quick summary of what we covered.

Episode 1: WorkManager: Basics

In our first episode, we explored the basics of WorkManager through the WorkManager codelab. We started by understanding how to define work we want done, and how to schedule the work. We then moved on to implementing different types of work: unique and periodic. Finally, we ended the episode by taking a look at app standby buckets to better understand how WorkManager schedules work.

If you’re new to WorkManager, we also recommend taking a look at the following articles:

Episode 2: WorkManager: Working in the background

The series continued with Ben giving a more in-depth look at how WorkManager deals with multi-threading. When working with threads, you have the option of using Executors, coroutines or RxJava, and Ben demonstrated each of these approaches with WorkManager. The episode concluded by demonstrating how to return a result when the work is completed so that the UI can be updated.

If you’re interested in using WorkManager with coroutines, we also recommend this article from Florina: WorkManager - Kotlin APIs

Episode 3: WorkManager: Advanced configuration and testing

In episode 3, we took a look at how to customize the initialization of WorkManager and support apps that span multiple processes. We’ve gotten a lot of questions from developers around testing and debugging, so Ben also dove into how to test your Workers, and useful debugging techniques.

Episode 4: Migrating from GCM NetworkManager and FirebaseJobDispatcher to WorkManager

In episode 4, we focused on how to migrate from old job scheduling libraries (GCMNetworkManager and FirebaseJobDispatcher) to WorkManager. Once your app starts targeting API level 30 and above, GCM NetworkManager and FirebaseJobDispatcher will no longer work on devices running Android Marshmallow (6.0) and above. If your app is still using either of those libraries, now is the time to update your apps to use WorkManager instead!

Episode 5: WorkManager with Hugo

Android GDE Hugo Visser talked about why he chose to use WorkManager in a health app he recently worked on and how the library has helped his development process.

Episode 6: Live Q&A

The series wrapped up with a live Q&A session where we answered your WorkManager related questions. Watch the recording to see all your questions answered, including future plans for WorkManager, handling duplicate work, retrying failed work, and more!

Source: Android Developers Blog

#AndroidDevJourney spotlight – March edition

Posted by Luli Perkins, Developer Relations Program Manager

For the March edition of #AndroidDevJourney, we’re highlighting Android developers from all over the world with many different experiences. Early this year, we launched the #AndroidDevJourney series to highlight our community on our social media accounts. Each Saturday, from January through June, we’ll feature a new developer on our Twitter account.

For a chance to be featured in our April spotlight series, tweet us your story using #AndroidDevJourney.

Wajahat Karim

Tell me about your journey to becoming an Android Developer and how you got started.

Since the age of 14, I was very interested in animations and graphic design. I used to watch advertisement animations or cricket match animations of player profiles on TV and wonder how I could create these. Later that year, when my sister purchased our home's first PC, I started learning Microsoft Paint and later Adobe Flash. I worked on Flash for about 11 years throughout high school, University, and my first three jobs in game development.

Game development was and has been my first love in computer science. But, Android became something special for me. It was NOT love-at-first sight because I hated Android when I first learned about it. I still don't know why. Coming from a poor family background, I got a fully-funded scholarship through Prime Minister ICT R&D Scholarship Program and enrolled in National University of Engineering & Technology (NUST), SEECS Islamabad campus.

In my 3rd semester, Android was at 2.2 Froyo. A company organized a workshop at our campus which was attended by high-level tech folks like CTOs, software architects, and lead engineers. University management decided to send three students to attend that workshop and I was lucky enough to be one of them. In simple words, the whole 3-days workshop was over my head. I was a newbie in C++ programming and didn't know anything about Java. And here I was trying to learn high-level Android.

After the workshop, I decided that Android was not for me. However, the university announced an open programming competition for any technology. But they gave extra points for Android submissions. This was my calling. In greed of those extra points, I took up the challenge. I borrowed the only Android book "Hello Android" from my teacher, Sir Shamyl bin Mansoor, and tried to learn as much as I could. Somehow, I managed to submit my first Android app which I showcased on a borrowed laptop with a very slow emulator of Android 2.2. To my surprise, I won it and got Rs. 100,000 prize money. First thing I bought was an Android phone and my journey started.

I started writing about it in a WordPress blog, organized workshops in different universities, made my final year project a 3D game in Adobe Flash, and AIR deployed on a Samsung Galaxy 10 tablet which had a new Android 4 Holo theme and the great Fragments.

After graduation, I got an opportunity from PacktPub (a book publishing company) to write a full book on Android. This was the best achievement I ever received. I managed to co-author two worldwide published 300+ page books (Learning Android Intents & Mastering Android Game Development) on Android in the following two years.

Having about seven years industry hands-on experience in Android development, I spend a lot of time on writing and sharing my knowledge with the community. I mostly write on my website and on Medium. Besides writing, I have been active in open source and have created some Android libraries like EasyFlipView, Room Explorer, etc.

In 2017, I started doing public speaking again. At first, it was a little tough to manage time while working a full-time job and freelance contracts, but it was worth it. I got more and more active in speaking and gave talks at events like Google IO Extended Karachi & Hyderabad in 2018 and 2019, DevFest 2019 Karachi, Pakistan's first DSC Summit, Kotlin Everywhere 2019, and other local events.

From these events, Sami Kizilbash noticed me and nominated me for becoming a Google Developers Expert. It was a tough time because of a serious medical situation with my father at that time, but a year later in February 2020 I became Pakistan's first Google Developers Expert in Android. I never thought that I would be a GDE in a field like Android. It is a big honor and achievement for me, along with a feeling of responsibility to help the community in a better way now. Android development has been my life fuel, career, brought bread for me and my family and happiness in developing and delivering more than 100 apps. With more than 2.5 billion Android devices today, this is an excellent career choice with high growth and potential for upcoming students and developers.

My GDE journey has been a fantastic one. I have enjoyed every moment of it, all the love I got from Google and fellow GDEs - including Joe Birch who actually inspired me to become GDE, Hasan Abid, Saurabh Arora, and Juhani Lehtimaki, and Saad Hamid who also helped me through the process. In all the chaos of 2020, it was a very talkative year for me, as I did 25+ online talks on Jetpack Compose animations concepts.

What’s one shortcut, tip, or hack you can’t live without?

I simply love how Mnemonic Bookmarks make code navigation so much faster and easier. When you are working on a large codebase, it becomes harder to remember which method was where and what was happening in another Fragment. Simply, press Ctrl + F11 and choose any number or character, let's say 1. Now, when you press Ctrl + 1, Android Studio will bring you back on that exact line.

What's the one piece of advice you wish someone would have given you when you started on your journey?

The Computer Science and Information Technology industry is changing and updating minute by minute. No matter what stage of your career you are at, you have to keep learning and updating your skillset. Android is moving at lightspeed, with alpha beta releases rolling out on a regular basis. So, it has become harder to catch up and learn. So, get a Twitter account, and follow the folks of #AndroidDev and you will be amazed how friendly the Twitter developer community is. You will learn new things every single day while scrolling the Twitter feed. And most importantly, don't forget to give back to the community. It could be through retweeting, or sharing your own code snippets, or writing articles, creating videos, or giving talks. In the end, you will see the more you give to the community, the more you gain back. So, it's all worth it.

Himanshu Singh

Tell me about your journey to becoming an Android Developer and how you got started.

My journey started from my college days. I got selected as an Applied CS facilitator for Android by Google in my second year of university. Because of this, I had to take sessions and help students complete a set of tasks as part of Bootcamp. In my college days I was not very good at Android, so when the opportunity came I took it upon myself to gain some knowledge of Android and then help people with their tasks. Learning to build apps that would be used by a lot of people helped me choose Android as a career. And that is how my journey to become an Android developer started.

What’s one shortcut, tip, or hack you can’t live without?

I like to use the Macro shortcut in Android Studio.

What's the one piece of advice you wish someone would have given you when you started on your journey?

As a beginner in any domain, not just Android, please keep asking questions on how to improve and learn from people in the community. Some of them might not answer your queries but a handful of them might. And in this way, you can learn and grow from their experience and when the time is right, you might be able to help someone in the coming future. This is the key to success!

Oluwasegun Famisa

Tell me about your journey to becoming an Android Developer and how you got started.

My journey in becoming an Android Developer started in 2010, my second year of university when I had the opportunity to participate in a program called “Entrepreneurial Programming and Research on Mobiles” (EPROM). It was a collaboration between MIT and Nokia, and my university was one of the campuses that ran the program. I did not study computer science, so the program was my first exposure to software development. I learned how to build J2ME apps and got exposure to different mobile technologies at the time.

Shortly after the program, I got a work-study opportunity at iQube Labs, where my mentor - James Fowe, who was building a mobile developer community in Nigeria - sent me a bunch of resources and tasks for me to learn how to build Android apps. The Android OS around 2010 was Android Froyo and that was the operating system on which I ran my “Hello world” on Android. Within the next year, I found myself building actual apps on Android Gingerbread.

I have since worked as an Android Developer in different companies ranging from small to mid-sized startups with millions of users, to publicly traded companies, all across many countries. I’ve had the opportunity of working with very brilliant folks that have contributed to my growth and learning.

My journey is not complete without talking about the developer community. I consider myself a product of the community and that’s why I try to give back every now and then when I have the opportunity.

I started getting involved in the developer community at my university - through various student groups, including my local GDG group then co-organized by Moyinoluwa Adeyemi (an Android GDE). I attended meetups and participated in developer challenges and hackathons.

Becoming a GDE for Android is a career milestone I never saw coming. It started in 2016 when John Kimani (Google DevRel manager for SSA) toured my office and we ran into each other at the door. I wasn’t prepared enough to become a GDE the first time my profile was reviewed, but with feedback, guidance, mentorship and hard work, I became an Android GDE in 2018.

I’m grateful to have had the opportunity to travel to so many countries around the world and meet members of the global Android Developer community. I’ve also given talks at conferences and meetups; including DevFests, Droidcon (Nairobi, Dubai, Berlin, Boston), and 360AnDev, to mention a few, about topics I enjoy - Kotlin, Design Systems, Jetpack Compose, and Developer Productivity Engineering.

What’s one shortcut, tip, or hack you can’t live without?

That’s such a tough one, but I’ll say my favourite AndroidDev tip right now is: use the Android code search tool - https://cs.android.com - and Android API documentation as often as possible. (See also: https://androidsrc.dev/)

The two resources have helped me in answering the “why is this not working” question and understanding what’s happening under the hood. A lot of times, I need to really understand what the Framework function I’m calling does, and the answer is almost always in the documentation or in the source code.

What's the one piece of advice you wish someone would have given you when you started on your journey?

I’ll give two for the price of one:

Structure and consistency are important when learning. One can’t possibly know everything, but one can try with enough of these two ingredients. Structured learning is becoming more and more accessible these days than it was, so one should take advantage of it, consistently - through codelabs, or courses and the likes.
Get used to reading official documentations and official source codes. This is a valuable and transferable skill regardless of the technology one works with, so I would advise not to shy away from it.

Karolina Pawlikowska

Tell me about your journey to becoming an Android Developer and how you got started.

From a young age, I’ve always loved science fiction books and movies – I always had a gut feeling that whatever career path I went down, it would have something to do with computers. Programming quickly became my favourite creative outlet – it started with creating websites and apps when I was 11, mainly as a way to enhance my other passions such as drawing and making puzzles for my friends.

I got my first Android phone when I was in high school and immediately knew it would open a whole new world of opportunities for me, so I picked up a few books and found a few online tutorials which got me started with code on my phone running Android 2.1 Eclair.

My first app was a flashcards maker. I needed something like that to help me learn English and I couldn’t find anything online - so I made my own!

Thanks to a few of my passion projects, including a flashcard maker app, I managed to quickly land a job as an Android Engineer while I was still completing my Computer Science degree at university. I then tried working across a few other areas in software engineering, but ultimately, Android was always my favourite and ended up becoming my specialty!

What’s one shortcut, tip, or hack you can’t live without?

It’s not quite a hack, but I honestly don’t know how I lived before ConstraintLayout became a thing! Oh – and Android Weekly’s mailing list, definitely one of the best ways to get all of the relevant news and tutorials in the Android world delivered directly to you every Monday!

What's the one piece of advice you wish someone would have given you when you started on your journey?

Looking back, I definitely recommend putting effort and being really intentional about seeking out other Android engineers around you. Once I started proactively attending meetups and working with other engineers, my skills and knowledge grew exponentially. Collaborating and bouncing around ideas has always been my favourite way to find creative and innovative solutions to problems I’m working on.

Source: Android Developers Blog

#AndroidDevJourney spotlight – March edition

Posted by Luli Perkins, Developer Relations Program Manager

For a chance to be featured in our April spotlight series, tweet us your story using #AndroidDevJourney.

Wajahat Karim

Tell me about your journey to becoming an Android Developer and how you got started.

What’s one shortcut, tip, or hack you can’t live without?

What's the one piece of advice you wish someone would have given you when you started on your journey?

Himanshu Singh

Tell me about your journey to becoming an Android Developer and how you got started.

What’s one shortcut, tip, or hack you can’t live without?

I like to use the Macro shortcut in Android Studio.

What's the one piece of advice you wish someone would have given you when you started on your journey?

Oluwasegun Famisa

Tell me about your journey to becoming an Android Developer and how you got started.

What’s one shortcut, tip, or hack you can’t live without?

What's the one piece of advice you wish someone would have given you when you started on your journey?

I’ll give two for the price of one:

Structure and consistency are important when learning. One can’t possibly know everything, but one can try with enough of these two ingredients. Structured learning is becoming more and more accessible these days than it was, so one should take advantage of it, consistently - through codelabs, or courses and the likes.
Get used to reading official documentations and official source codes. This is a valuable and transferable skill regardless of the technology one works with, so I would advise not to shy away from it.

Karolina Pawlikowska

Tell me about your journey to becoming an Android Developer and how you got started.

My first app was a flashcards maker. I needed something like that to help me learn English and I couldn’t find anything online - so I made my own!

What’s one shortcut, tip, or hack you can’t live without?

What's the one piece of advice you wish someone would have given you when you started on your journey?

Source: Android Developers Blog

High Performance Game Audio with Oboe

Posted by Dan Galpin

We've added the Oboe C++ audio library to the Android Game SDK. Oboe's support of high-performance, low-latency audio across the widest range of Android devices is the right choice for most game developers.

Single API

On Android devices running Android 8.1 (API level 27) and higher, Oboe takes advantage of the improved performance and features of AAudio while maintaining backward compatibility (using OpenSL ES) with Android 4.1 (API level 16) and higher. Oboe also adds key features on top of the platform APIs to improve the audio developer experience, such as resampling, format conversion, and dynamic latency tuning. It performs audio data transformations, such as channel count conversion, when necessary to improve performance on selected devices, and has workarounds for other device-specific behaviors that improve the robustness of your audio code. In short, Oboe is now the recommended way to write audio code in C/C++ on Android.

Integrating Oboe

There are two primary ways to incorporate Oboe library prebuilts into your project. If you're using the Android Gradle plugin version 4.1.0 or higher along with CMake, and are using or can enable shared STL, enabling Oboe is as easy as adding Oboe to your Gradle dependencies, enabling prefabs, and adding a few lines to your CMakeLists file.

You can also integrate Oboe by statically linking using the Android Game SDK. Begin by downloading the library and checking it into your source control system. You need to be using minSdkVersion of 16 or higher with NDK release 18 or higher. Then, to specify the version of the game SDK to link in that's been compiled for the given ABI, API level, NDK, and STL combination, add a compiler include path in this form:

gamesdk/libs/[architecture]_API[apiLevel]_NDK[ndkVersion]_[stlVersion]_Release
Example: gamesdk/libs/arm64-v8a_API24_NDK18_cpp_static_Release

Then add -loboe_static to your linker command. Since you don't need to bundle the liboboe.so shared library, static linking gives you a smaller code footprint. If the ABI, API level, NDK, and STL combination doesn't have a precompiled version available for your settings, you can alternately link against the shared library. We have more guidance, including how to configure CMake for static libraries, in our developer documentation.

Oboe Basics

To output audio, you begin by creating a stream with the required properties, including a callback that is used when the stream requires new data.

oboe::AudioStreamBuilder builder;
builder.setPerformanceMode(oboe::PerformanceMode::LowLatency)
  ->setSharingMode(oboe::SharingMode::Exclusive)
  ->setDataCallback(myCallback)
  ->setFormat(oboe::AudioFormat::Float);

You'll then populate the audio data inside of the callback. If the stream creates successfully, that means you got the requested stream type. If you didn't specify these types, you'll have to query to see what format was returned.

class MyCallback : public oboe::AudioStreamDataCallback {
public:
    oboe::DataCallbackResult
    onAudioReady(oboe::AudioStream *audioStream, void *audioData, int32_t numFrames) {
        // We requested AudioFormat::Float
        auto *outputData = static_cast<float *>(audioData);
        // TODO: populate audioData here
        return oboe::DataCallbackResult::Continue;
    }
};

For full details on using Oboe, check out the documentation, code samples and API reference. There's even a codelab which shows you how to build a simple rhythm-based game.

If you have any issues, please file them here. We'd love to hear from you.

Source: Android Developers Blog

Android 12 Developer Preview 2

Posted by Dave Burke, VP of Engineering

Last month we shared the first preview of Android 12, an early look at the next version of Android. Today we’re bringing you the next milestone build in this year’s release, with more new features and changes for you to try with your apps. Our program of early previews is driven by our core philosophy of openness and collaboration with you, our community. Your input helps us make Android a better platform for developers and users, so keep the feedback coming!

In Android 12 we’re making the OS smarter, easier to use, and better performing, with privacy and security at the core. We’re also working to give you new tools for building great experiences for users, whether they’re using phones, laptops, tablets, TVs, or cars. Some things to look for in today’s release include new rounded corners APIs, improved picture-in-picture APIs, better companion device management, easier effects like blur and color filter, app overlay controls, and more.

There’s a lot to check out in Developer Preview 2 - read on for a few highlights and visit the Android 12 developer site for details and downloads for Pixel. 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.

Trust and safety

We’re continuing to focus on giving users more transparency and control while keeping their devices and data secure. In today’s release, we’ve added some new features to check out and test with your apps.

App overlay controls - Android’s system alert window gives apps a way to get users’ attention for important actions by showing an overlay on top of the active app. These windows can interrupt the user, though, so we already require apps to request permission before displaying them. Now in Android 12 we’re giving you control over whether these overlays can be shown over your content. After you’ve declared a new permission, your app can call Window#setHideOverlayWindows() to indicate that all TYPE_APPLICATION_OVERLAY windows should be hidden when your app’s window is visible. You might choose to do this when displaying sensitive screens, such as transaction confirmation flows. More here.

Extended security for lockscreen notification actions - Android 12 adds finer-grained privacy and security controls for notifications displayed on the device lockscreen. You can now configure notification actions so that when triggered from the lockscreen, they will always generate an authentication challenge. This extends the notification visibility controls already available through the notification APIs. For example, this enables a messaging app to require authentication before deleting a message or marking it as read. More here.

Access to app digests - For apps that need to validate the integrity of app packages installed on Android devices, we’re introducing a new API that lets you query the platform directly for the checksum of an installed app. You can choose from several digest algorithms such as SHA256, SHA512, Merkle Root, and others. To request a checksum, call PackageManager.requestChecksums() with an app’s package name, the checksum types you need, the installer certs you trust, and a listener to receive the checksums. The platform returns the matching checksums, either precomputed and provided by the installer app (such as Google Play) or computed by the platform. Results are filtered based on package visibility guidelines, so you’ll need to declare the packages of interest in your manifest. This new API provides a simpler, more efficient way to obtain checksums and gives you the stability of a standard, public API that’s optimized for speed and security. For backward compatibility, we’re working on a Jetpack library that provides the same functionality back to API 15 - watch for more details coming soon.

You can read more about these and other privacy and security changes here.

Better user experience tools

We’re working to give you more tools to help you deliver a polished experience and better performance for users. Here are some of the updates in today’s release.

Support for Rounded corners - Many modern devices use screens with rounded corners, giving them a clean modern look, but also introducing some extra considerations for app developers. To deliver a great UX on these devices, developers need to account for the rounded corners and adjust any nearby UI elements to prevent them from being truncated.

To help with this, we’re introducing new APIs to let you query for rounded corners and get their details. A RoundedCorner holds the details for a corner, including its radius, centerpoint, and other data. You can call Display.getRoundedCorner() to get the absolute details for each rounded corner. You can also call WindowInsets.getRoundedCorner() to get the corner details relative to your app’s bounds. With these, you can manage the position of UI elements and content as needed. More here.

Picture in Picture (PIP) improvements - for people using gesture nav, we’ve improved how apps transition to picture-in-picture (PIP) mode on swipe up-to-home. If an app enables auto-PIP, the system now directly transitions the app to PIP mode on up-to-home, instead of waiting for the up-to-home animation to complete. This makes the transition smoother and improves perceived performance. We’ve also improved PIP window resizing for non-video content. Apps can now enable seamless resize to let the system resize the PIP Activity when needed. Android 12 also supports stashing the PiP window by dragging it to the left or right edge of the screen. Also, to make PIP windows easier to manipulate, we’ve updated the tap behaviors. Single-tapping now displays controls, and double-tapping toggles the PIP window size. More here.

Keeping companion device apps awake - For apps that manage companion devices like smartwatches and fitness trackers, it can be a challenge to make sure the app is running and connected whenever an associated companion device is nearby. To make this easier, we’re extending the Companion Device Manager with a new CompanionDeviceService API. Apps that manage companion devices can implement this service to let the system wake the app whenever the associated companion device is nearby. The system keeps the service bound whenever the device is nearby, and notifies the service when the device goes in and out of range or is turned off, to let the app clean up state as needed. Apps can also use a new companion device profile when connecting to a watch, which simplifies enrollment by bundling related permissions into a single grant. More here.

Bandwidth estimation improvements - for developers who need to know the typical bandwidth available to each user so you can tailor their experience, we now provide improved bandwidth estimation. We’ve enhanced the existing bandwidth estimation APIs to let you retrieve an estimate of aggregate throughput per carrier or Wi-Fi SSID, network type, and signal level, for all users on the device. The new estimation is likely to be easier and more accurate than most other estimation methods, give it a try and let us know how it works for you.

Easier blurs, color filters and other effects - In Android 12, we’re making it easier to apply common graphics effects to your Views and rendering hierarchies. You can use RenderEffect to apply blurs, color filters, and more to any RenderNode. You can combine these effects as chain effects (which compose an inner and outer effect in order) or blend them. You can also apply effects directly to Views (leveraging the underlying RenderNode) by calling View.setRenderEffect(RenderEffect).

view.setRenderEffect(RenderEffect.createBlurEffect(radiusX, radiusY, SHADER_TILE_MODE))

Blurring a View with RenderEffect

This allows you to blur the contents of an ImageView without having to get the bitmap data, process the image, create a new Bitmap, and set it back into the ImageView. RenderEffect leverages the existing rendering pipeline to minimize excess calculation.

Give these a try and let use know what you think! More here.

You can also create a frosted glass effect for your window background using a new Window.setBackgroundBlurRadius() API. With this you can set a radius to control the density and scope and the platform applies the blur to the background content within the bounds of your app’s window only. You can also use blurBehindRadius to blur all of the content behind the window to create a depth effect for a floating window.

A dialog window with background blur and blur behind...

App compatibility

We’re working to make updates faster and smoother by prioritizing app compatibility as we roll out new platform versions. In Android 12, we’ve made most app-facing changes opt-in to give you more time, and we’ve updated our tools and processes to help you get ready sooner.

With Developer Preview 2, we’re well into the release and continuing to improve overall stability, so now is the time to try the new features and changes and give us your feedback. We’re especially looking for input on our APIs, as well as details on how the platform changes affect your apps. Please visit the feedback page to share your thoughts with us or report issues.

It’s also a good 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 12 Beta 1. There’s no need to change your app’s targetSdkVersion at this time, but we do recommend using the behavior change toggles to get a preliminary idea of how your app might be affected by opt-in changes in Android 12.

As we reach Platform Stability in August 2021, all of the app-facing system behaviors, SDK/NDK APIs, and non-SDK lists will be finalized. At that point, you can wind up your final compatibility testing and release a fully compatible version of your app, SDK, or library. More on the timeline for developers is here.

App compatibility toggles in Developer Options.

Get started with Android 12

The Developer Preview has everything you need to try the Android 12 features, test your apps, and give us feedback. You can get started today by flashing a device system image to a Pixel 3 / 3 XL, Pixel 3a / 3a XL, Pixel 4 / 4 XL, Pixel 4a / 4a 5G, or Pixel 5 device or using the Android Emulator. If you’ve already installed a preview build to your Pixel device, you’ll automatically get future updates over-the-air for all later previews and Betas. More details on how to get Android 12 are here.

You can also test your apps on Android TV using today’s release and try the all-new Google TV experience. Learn more here and get started with your ADT-3 developer kit.

For complete information, visit the Android 12 developer site.

Source: Android Developers Blog

Android Dev Challenge Finale: Weather app

Posted by Jolanda Verhoef, Developer Relations Engineer

Let your creativity shine in the final week of the #AndroidDevChallenge! Last week we asked you to be fast, but for this final week we ask you to bring your 'A' game. Here’s the challenge:

Week #4: Weather app 🌤

Create a single-screen weather forecast app. You have until March 23rd, 23:59 PST to submit your entry.¹

Your UI must be fully built in Compose. You can use fake weather data.

We will judge your submission on these four categories:

Visual beauty
Novelty of idea
Code quality
Overall execution (including accessibility)

To help implement a beautiful design, check out the Compose documentation on layouts, theming, and graphics. Think of novel uses of animations and gestures. Improve your code quality with architecture and testing. And for overall execution, make sure to read about accessibility.

Your solution must be implemented in a public GitHub repository. Make a copy of this Github repository template and follow the instructions in the README. The template contains a basic Hello World! in Compose and a continuous integration setup.

The App Submission must, at a minimum, support English language use.

This week’s prize: 5 x Google Pixel 5!

This week you have a chance of winning a Google Pixel 5, the ultimate 5G Google phone! We’ll be giving away one Google Pixel 5 for the winner of each of the four categories, and one for the best of the best submission.²

Help make Jetpack Compose better

Community is at the heart of Jetpack Compose and your feedback helps us build a better product:

File issues with Jetpack Compose on the official issue tracker.
Sign up to be part of the Jetpack Compose research studies.

Notes

Please review the link for the full official rules associated with the entry. ↩
If you don’t live in a country where the Pixel 5 is available, when you win we’ll instead send you an electronics gift card valued at US$699. ↩

Source: Android Developers Blog

Boosting developer success on Google Play

Posted by Sameer Samat, VP, Product Management

Helping developers build sustainable businesses is a core part of Google Play’s mission. We work with partners every day to understand the challenges they face and help them bring their innovative ideas to life. Getting a new app off the ground and into orbit is not easy! To aid their quest for growth we provide a broad range of support, from powerful marketing tools and actionable data in the Play Console, education via Play Academy, best practices and thought leadership resources, programs such as the Indie Games Festival, Indie Corner, and accelerator programs around the world. We’re always looking for new ways to give them an added boost.

Starting on July 1, 2021 we are reducing the service fee Google Play receives when a developer sells digital goods or services to 15% for the first $1M (USD) of revenue every developer earns each year. With this change, 99% of developers globally that sell digital goods and services with Play will see a 50% reduction in fees. These are funds that can help developers scale up at a critical phase of their growth by hiring more engineers, adding to their marketing staff, increasing server capacity, and more.

While these investments are most critical when developers are in the earlier stages of growth, scaling an app doesn’t stop once a partner has reached $1M in revenue — we’ve heard from our partners making $2M, $5M and even $10M a year that their services are still on a path to self-sustaining orbit. This is why we are making this reduced fee on the first $1M of total revenue earned each year available to every Play developer, regardless of size. We believe this is a fair approach that aligns with Google’s broader mission to help all developers succeed. We look forward to sharing full details in the coming months.

As a platform we do not succeed unless our partners succeed. Android and Google Play have always listened to our developer partners from around the world and we continue to take their input into account as we build and run the ecosystem. We look forward to seeing more businesses scale to new heights on Android, and to further discussions with our developer community to find new ways to support them technically and economically as they build their businesses.