Google Data

Posted by Shanee Nishry, Developer Advocate

As you may know, high resolution textures contribute to better graphics and a more impressive game experience. Adaptive Scalable Texture Compression (ASTC) helps solve many of the challenges involved including reducing memory footprint and loading time and even increase performance and battery life.

If you have a lot of textures, you are probably already compressing them. Unfortunately, not all compression algorithms are made equal. PNG, JPG and other common formats are not GPU friendly. Some of the highest-quality algorithms today are proprietary and limited to certain GPUs. Until recently, the only broadly supported GPU accelerated formats were relatively primitive and produced poor results.

With the introduction of ASTC, a new compression technique invented by ARM and standardized by the Khronos group, we expect to see dramatic changes for the better. ASTC promises to be both high quality and broadly supported by future Android devices. But until devices with ASTC support become widely available, it’s important to understand the variety of legacy formats that exist today.

We will examine preferable compression formats which are supported on the GPU to help you reduce .apk size and loading times of your game.

Texture Compression

Popular compressed formats include PNG and JPG, which can’t be decoded directly by the GPU. As a consequence, they need to be decompressed before copying them to the GPU memory. Decompressing the textures takes time and leads to increased loading times.

A better option is to use hardware accelerated formats. These formats are lossy but have the advantage of being designed for the GPU.

This means they do not need to be decompressed before being copied and result in decreased loading times for the player and may even lead to increased performance due to hardware optimizations.

Hardware Accelerated Formats

Hardware accelerated formats have many benefits. As mentioned before, they help improve loading times and the runtime memory footprint.

Additionally, these formats help improve performance, battery life and reduce heating of the device, requiring less bandwidth while also consuming less energy.

There are two categories of hardware accelerated formats, standard and proprietary. This table shows the standard formats:

ETC1	Supported on all Android devices with OpenGL ES 2.0 and above. Does not support alpha channel.
ETC2	Requires OpenGL ES 3.0 and above.
ASTC	Higher quality than ETC1 and ETC2. Supported with the Android Extension Pack.

As you can see, with higher OpenGL support you gain access to better formats. There are proprietary formats to replace ETC1, delivering higher quality and alpha channel support. These are shown in the following table:

ATC	Available with Adreno GPU.
PVRTC	Available with a PowerVR GPU.
DXT1	S3 DXT1 texture compression. Supported on devices running Nvidia Tegra platform.
S3TC	S3 texture compression, nonspecific to DXT variant. Supported on devices running Nvidia Tegra platform.

That’s a lot of formats, revealing a different problem. How do you choose which format to use?

To best support all devices you need to create multiple apks using different texture formats. The Google Play developer console allows you to add multiple apks and will deliver the right one to the user based on their device. For more information check this page.

When a device only supports OpenGL ES 2.0 it is recommended to use a proprietary format to get the best results possible, this means making an apk for each hardware.

On devices with access to OpenGL ES 3.0 you can use ETC2. The GL_COMPRESSED_RGBA8_ETC2_EAC format is an improved version of ETC1 with added alpha support.

The best case is when the device supports the Android Extension Pack. Then you should use the ASTC format which has better quality and is more efficient than the other formats.

Adaptive Scalable Texture Compression (ASTC)

The Android Extension Pack has ASTC as a standard format, removing the need to have different formats for different devices.

In addition to being supported on modern hardware, ASTC also offers improved quality over other GPU formats by having full alpha support and better quality preservation.

ASTC is a block based texture compression algorithm developed by ARM. It offers multiple block footprints and bitrate options to lower the size of the final texture. The higher the block footprint, the smaller the final file but possibly more quality loss.

Note that some images compress better than others. Images with similar neighboring pixels tend to have better quality compared to images with vastly different neighboring pixels.

Let’s examine a texture to better understand ASTC:

This bitmap is 1.1MB uncompressed and 299KB when compressed as PNG.

Compressing the Android jellybean jar texture into ASTC through the Mali GPU Texture Compression Tool yields the following results.

Block Footprint	4×4	6×6	8×8
Memory	262KB	119KB	70KB
Image Output
Difference Map
5x Enhanced Difference Map

As you can see, the highest quality (4×4) bitrate for ASTC already gains over PNG in memory size. Unlike PNG, this gain stays even after copying the image to the GPU.

The tradeoff comes in the detail, so it is important to carefully examine textures when compressing them to see how much compression is acceptable.

Conclusion

Using hardware accelerated textures in your games will help you reduce the size of your .apk, runtime memory use as well as loading times.

Improve performance on a wider range of devices by uploading multiple apks with different GPU texture formats and declaring the texture type in the AndroidManifest.xml.

If you are aiming for high end devices, make sure to use ASTC which is included in the Android Extension Pack.

Posted by Chris Sells, Product Manager, Cloud Tools for Android Studio

Cloud Tools for Android Studio allows you to simultaneously build the service- and client-side of your mobile app. Earlier this month, we announced the release of Android Studio 1.0 that showed just how much raw functionality there is available for Android app developers. However, the client isn’t the whole picture, as most mobile apps also need one or more web services. It was for this reason that the Cloud Tools for Android Studio were created.

Cloud Tools put the power of Google App Engine in the same IDE alongside of your mobile client, giving you all the same Java language tools for both sides of your app, as well as making it far easier for you to keep them in sync as each of them changes.

Getting Started

To get started with Cloud Tools for Android Studio, add a New Module to your Android Studio project, choose Google Cloud Module and you’ll have three choices:

You can add three Google Cloud module types to your Android Studio project

The Java Servlet Module gives you a plain servlet class for you to implement as you see fit. If you’d like help building your REST endpoints with declarative routing and HTTP verbs and automatic Java object serialization to and from JSON, then you’ll want the Java Endpoints Module. If you want the power of endpoints, along with the ability to send notifications from your server to your clients, then choose Backend with Google Cloud Messaging.

Once you’re done, you’ll have your service code right next to your client code:

You can build your mobile app’s client and service code together in a single project

Not only does this make it very convenient to build and test your entire end-to-end, but we also dropped a little extra something into your app’s build.gradle file:

The android-endpoints configuration build step in your build.gradle file creates a client-side library for your server-side endpoint

The updated Gradle file will now create a library for use in your app’s client code that changes when your service API changes. This library lets you call into your service from your client and provides full code completion as you do:

The client-side endpoint library provides code completion and documentation

Instead of writing the code to create HTTP requests by hand, you can make calls via the library in a typesafe manner and the marshalling from JSON to Java will be handled for you, just like on the server-side (but in reverse, of course).

Endpoints Error Detection

Meanwhile, back on the server-side, as you make changes to your endpoints, we’re watching to make sure that they’re in good working order even before you compile by checking the attributes as you type:

Cloud Tools will detect errors in your endpoint attributes

Here, Cloud Tools have found a duplicate name in the ApiMethod attribute, which is easy to do if you’re creating a new method from an existing method.

Creating an Endpoint from an Objectify Entity

If, as part of your endpoint implementation, you decide to take advantage of the popular Objectify library, you’ll find that Cloud Tools provides special support for you. When you right-click (or control-click on the Mac) on a file containing an Objectify entity class, you’ll get the Generate Cloud Endpoint from Java class option:

The generate Cloud Endpoint from Java class option will create a CRUD endpoint for you

If you’re running this option on a Java class that isn’t built with Objectify, then you’re going to get an endpoint with empty methods for get and insert operations that you can implement as appropriate. However, if you do this with an Objectify entity, you’ll get a fully implemented endpoint:

Cloud Tools has built-in support for generating Objectify-based cloud endpoint implementations

Using your Cloud Endpoint

As an Android developer, you’re used to deploying your client first in the emulator and then into a local device. Likewise, with the service, you’ll want to test first to your local machine and then, when you’re ready, deploy into a Google App Engine project. You can run your service app locally by simply choosing it from the Configurations menu dropdown on the toolbar and pressing the Run button:

The Configurations menu in the toolbar lets you launch your service for testing

This will build and execute your service on http://localhost:8080/ (by default) so that you can test against it with your Android app running in the emulator. Once you’re ready to deploy to Google Cloud Platform, you can do so by selecting the Deploy Module to App Engine option from the Build menu, where you’ll be able to choose the source module you want to deploy, log into your Google account and pick the target project to which you’d like to deploy:

The Deploy to App Engine dialog will use your Google credentials to enumerate your projects for you

Cloud Tools beta required some extra copying and pasting to get the Google login to work, but all of that’s gone now in this release.

What’s Next?

We’re excited to get this release into your hands, so if you’ve haven’t downloaded it yet, then go download Android Studio 1.0 right now! To take advantage of Cloud Tools for Android Studio, you’ll want to sign up for a free Google Cloud Platform trial. Nothing is stopping you from building great Android apps from front to back. If you’ve got suggestions, drop us a line so that we can keep improving. We’re just getting started putting Google Cloud Platform tools in your hands. We can’t wait to see what you’ll build.

Posted by Benjamin Frenkel, Product Manager, Play Games

In an effort to supercharge our Google Play games services (GPGS) developer tools, we’re introducing the Game services Publishing API, a revamped Unity Plugin, additional enhancements to the C++ SDK, and improved Leaderboard Tamper Protection.

Let’s dig into what’s new for developers:

Publishing API to automate game services configuration

At Google I/O this past June, the pubsite team launched the Google Play Developer Publishing APIs to automate the configuration and publishing of applications to the Play store. Game developers can now also use the Google Play game services Publishing API to automate the configuration and publishing of game services resources, starting with achievements and leaderboards.

For example, if you plan on publishing your game in multiple languages, the game services Publishing API will enable you to pull translation data from spreadsheets, CSVs, or a Content Management System (CMS) and automatically apply those translations to your achievements.

Early adopter Square Enix believes the game services Publishing API will be an indispensable tool to manage global game rollouts:

Achievements are the most used feature in Google Play game services for us. As our games support more languages, achievement management has become increasingly difficult. With the game services Publishing API, we can automate this process, which is really helpful. The game services Publishing API also comes with great samples that we were able to easily customize for our needs

Keisuke Hata, Manager / Technical Director, SQUARE ENIX Co., Ltd.

To get started today, take a look at the developer documentation here.

Updated Unity plugin and Cross-platform C++ SDK

• Unity plugin Saved Games support: You can now take advantage of the Saved Games feature directly from the Unity plugin, with more storage and greater discoverability through the Play Games app
• New Unity plugin architecture: We’ve rewritten the plugin on top of our cross-platform C++ SDK to speed up feature development across SDKs and increase our responsiveness to your feedback
• Improved Unity generated Xcode project setup: You now have a much more robust way to generate Xcode projects integrated with Google Play Game Services in Unity
• Updated and improved Unity samples: We’ve updated our sample codes to make it easier for first time developers to integrate Google Play games services
• C++ SDK support for iPhone 6 Plus: You can now take advantage of the out-of-box games services UI (e.g., for leaderboards and achievements) for larger form factor devices, such as the iPhone 6 Plus

We also include some important bug fixes and stability improvements. Check out the release notes for the Unity Plugin and the getting started page for the C++ SDK for more details.

Leaderboard Tamper Protection

Turn on Leaderboard Tamper Protection to automatically hide suspected tampered scores from your leaderboards. To enable tamper protection on an existing leaderboard, go to your leaderboard in the Play developer console and flip the “Leaderboard tamper protection” toggle to on. Tamper protection will be on by default for new leaderboards.Learn more.

To learn more about cleaning up previously submitted suspicious scores refer to the Google Play game services Management APIs documentation or get the web demo console for the Management API directly from github here.

In addition, if you prefer command-line tools, you can use the python-based option here.

Posted by Hoi Lam, Developer Advocate, Android Wear

What’s a better holiday gift than great performance? You’ve got a great watch face idea — now, you want to make sure the face you’re presenting to the world is one of care and attention to detail.

At the core of the watch face’s process is an onDraw method for canvas operations. This allows maximum flexibility for your design, but also comes with a few performance caveats. In this blog post, we will mainly focus on performance using the real life journey of how we optimised the Santa Tracker watch face, more than doubling the number of fps (from 18 fps to 42 fps) and making the animation sub-pixel smooth.

Starting point – 18 fps

Our Santa watch face contains a number of overlapping bitmaps that are used to achieve our final image. Here’s a list of them from bottom to top:

1. Background (static)
2. Clouds which move to the middle
3. Tick marks (static)
4. Santa figure and sledge (static)
5. Santa’s hands – hours and minutes
6. Santa’s head (static)

The journey begins with these images…

Large images kill performance (+14 fps)

Image size is critical to performance in a Wear application, especially if the images will be scaled and rotated. Wasted pixel space (like Santa’s arm here) is a common asset mistake:

Before: 584 x 584 = 341,056 pixels	After: 48*226 = 10,848 (97% reduction)

It’s tempting to use bitmaps from the original mock up that have the exact location of watch arms and components in absolute space. Sadly, this creates problems, like in Santa’s arm here. While the arm is in the correct position, even transparent pixels increase the size of the image, which can cause performance problems due to memory fetch. You’ll want to work with your design team to extract padding and rotational information from the images, and rely on the system to apply the transformations on our behalf.

Since the original image covers the entire screen, even though the bitmap is mostly transparent, the system still needs to check every pixel to see if they have been impacted. Cutting down the area results in significant gains in performance. After correcting both of the arms, the Santa watch face frame rate increased by 10 fps to 28 fps (fps up 56%). We saved another 4 fps (fps up 22%) by cropping Santa’s face and figure layer. 14 fps gained, not bad!

Combine Bitmaps (+7 fps)

Although it would be ideal to have the watch tick marks on top of our clouds, it actually does not make much difference visually as the clouds themselves are transparent. Therefore there is an opportunity to combine the background with the ticks.

+

When we combined these two views together, it meant that the watch needed to spend less time doing alpha blending operations between them, saving precious CPU time. So, consider collapsing alpha blended resources wherever we can in order to increase performance. By combining two full screen bitmaps, we were able to gain another 7 fps (fps up 39%).

Anti-alias vs FilterBitmap flags – what should you use? (+2 fps)

Android Wear watches come in all shapes and sizes. As a result, it is sometimes necessary to resize a bitmap before drawing on the screen. However, it is not always clear what options developers should select to make sure that the bitmap comes out smoothly. With canvas.drawBitmap, developers need to feed in a Paint object. There are two important options to set – they are anti-alias and FilterBitmap. Here’s our advice:

• Anti-alias does not do anything for bitmaps with transparent edges. We often switch on the anti-alias option by default as developers when we are creating a Paint object. However, this option only really makes sense for vector objects. For bitmaps, this is used to blend the rectangular edges if it is rotated or skewed and it has no impact if the edge pixels are transparent (as we would imagine most watch face arms would be). The hand on the left below has anti-alias switched on, the one on the right has it switched off. So turn off anti-aliasing for bitmaps to gain performance back. For our watch face, we gained another 2 fps (fps up 11%) by switching this option off.

• 

• Switch on FilterBitmap for all bitmap objects which are on top of other objects – this option smooths the edges when drawBitmap is called. This should not be confused with the filter option on Bitmap.createScaledBitmap for resizing bitmaps. We need both to be turned on. The bitmaps below are the magnified view of Santa’s hand. The one on the left has FilterBitmap switched off and the one on the right has FilterBitmap switched on.

Eliminate expensive calls in the onDraw loop (+3 fps)

onDraw is the most critical function call in watch faces. It’s called for every drawable frame, and the actual painting process cannot move forward until it’s finished. As such, our onDraw method should be as light and as performant as possible. Here’s some common problems that developers run into that can be avoided:

1. Do move heavy and common code to a precompute function – e.g. if we commonly grab R.array.cloudDegrees, try doing that in onCreate, and just referencing it in the onDraw loop.
2. Don’t repeat the same image transform in onDraw – it’s common to resize bitmaps at runtime to fit the screen size but this is not available in onCreate. To avoid resizing the bitmap over and over again in onDraw, override onSurfaceChanged where width and height information are available and resize images there.
3. Don’t allocate objects in onDraw – this leads to high memory churn which will force garbage collection events to kick off, killing frame rates.
4. Do analyze the CPU performance by using a tool such as the Android Device Monitor. It’s important that the onDraw execution time is short and occurs in a regular period.

Following these simple rules will improve rendering performance drastically.

In the first version, the Santa onDraw routine has a rogue line:

int[] cloudDegrees = 
    getResources().getIntArray(R.array.cloudDegrees);

This loads the int array on every call from resources which is expensive. By eliminating this, we gained another 3 fps (fps up 17%).

Sub-pixel smooth animation (-2 fps)

For those keeping count, we should be 44 fps, so why is the end product 42 fps? The reason is a limitation with canvas.drawBitmap. Although this command takes left and top positioning settings as a float, the API actually only deals with integers if it is purely translational for backwards compatibility reasons. As a result, the cloud can only move in increments of a whole pixel resulting in janky animations. In order to be sub-pixel smooth, we actually need to draw and then rotate rather than having pre-rotate clouds which moves towards Santa. This additional rotation costs us 2 fps. However, the effect is worthwhile as the animation is now sub-pixel smooth.

Before – fast but janky and wobbly

for (int i = 0; i 


After - slightly slower but sub-pixel smooth

for (int i = 0; i 




Before: Integer translation values create janky, wobbly animation. After: smooth sailing!

Quality on every wrist

The watch face is the most prominent UI element in Android Wear. As craftspeople, it is our responsibility to make it shine. Let’s put quality on every wrist!

Posted by Trevor Johns, Developer Programs Engineer

With the launch of Android 5.0 Lollipop, we’ve added more than 20 new code samples demonstrating how to implement some of the great new features of this release. To access the code samples, you can easily import them in Android Studio 1.0 using the new Samples Wizard.

Go to File > Import Sample in order to browse the available samples, which include a description and preview for each. Once you’ve made your selection, select “Next” and a new project will be automatically created for you. Run the project on an emulator or device, and feel free to experiment with the code.

Alternatively, you can browse through them via the Samples browser on the developer site. Each sample has an Overview description, Project page to browse app file structure, and Download link for obtaining a ZIP file of the sample. As a third option, code samples can also be accessed in the SDK Manager by downloading the SDK samples for Android 5.0 (API 21) and importing them as existing projects into your IDE.

Material Design

When adopting material design, you can refer to our collection of sample code highlighting material elements:

• Floating action button
• Reveal effect
• CardView
• Drawable tinting
• Elevation
• Drag-and-drop with elevation
• View clipping
• Animation interpolators

For additional help, please refer to our design checklist, list of key APIs and widgets, and documentation guide.

To view some of these material design elements in action, check out the Google I/O app source code.

Platform

Lollipop brings the most extensive update to the Android platform yet. The Overview screen allows an app to surface multiple tasks as concurrent documents. You can include enhanced notifications with this sample code, which shows you how to use the lockscreen and heads-up notification APIs.

We also introduced a new Camera API to provide developers more advanced image capture and processing capabilities. These samples detail how to use the camera preview and take photos, how to record video, and implement a real-time high-dynamic range camera viewfinder.

Elsewhere, Project Volta encourages developers to make their apps more battery-efficient with new APIs and tools. The JobScheduler sample demonstrates how you can schedule background tasks to be completed later or under specific conditions.

For those interested in the enterprise device administration use case, there are sample apps on setting app restrictions and creating a managed profile.

Android Wear

For Android Wear, we have a speed tracker sample to show how to take advantage of GPS support on wearables. You can browse the rest of the Android Wear samples too, and here are some highlights that demonstrate the unique capabilities of wearables, such as data synchronization, notifications, and supporting round displays:

• DataLayer
• FindMyPhone
• GridViewPager
• Notifications
• RecipeAssistant
• SynchronizedNotifications
• WatchViewStub

Android TV

Extend your app for Android TV using the Leanback library described in this training guide and sample.

To try out a game that is specifically optimized for Android TV, download Pie Noon from Google Play. It’s an open-source game developed in-house at Google that supports multiple players using Bluetooth controllers or touch controls on mobile devices.

Android Auto

For the use cases highlighted in the Introduction to Android Auto DevByte, we have two code samples. The Media Browser sample (DevByte) demonstrates how easy it is to make an audio app compatible with Android Auto by using the new Lollipop media APIs, while the Messaging sample (DevByte) demonstrates how to implement notifications that support replies using speech recognition.

Google Play services

Since we’ve discussed sample resources for the Android platform and form factors, we also want to mention that there are existing samples for Google Play services. With Google Play services, your app can take advantage of the latest Google-powered APIs such as Maps, Google Fit, Google Cast, and more. Access samples in the Google Play services SDK or visit the individual pages for each API on the developer site. For game developers, you can reference the Google Play Games services samples for how to add achievements, leaderboards, and multiplayer support to your game.

Check out a sample today to help you with your development!

Posted by Paul Rashidi, Developer Programs Engineer

We’ve been working on a new toolchain for Android that’s designed to improve build times and simplify development by reducing dependencies on other tools. Today, we’re introducing you to Jack (Java Android Compiler Kit) and Jill (Jack Intermediate Library Linker), the two tools at the core of the new toolchain.

We are making an early, experimental version of Jack and Jill available for testing with non-production versions of your apps. This post describes how the toolchain works, how to configure it, and how to let us know of your feature requests and any bugs you find.

So how does it work?

When the new tool chain is enabled, Jill will translate any libraries you are referencing to a new Jack library file (.jack). This prepares them to be quickly merged with other .jack files. The Android Gradle plugin and Jack collect any .jack library files, along with your source code, and compiles them into a set of dex files. During the process, Jack also handles any requested code minification. The output is then assembled into an APK file as normal. We also include support for multiple dex files, if you have enabled that support.

How do I use it?

Jack and Jill are already available in the 21.1.1+ Build Tools for Android Studio. Complementary Gradle support is also currently available in the Android 1.0.0+ Gradle plugin. To get started, all you need to do is make sure you’re using these versions of the tooling and then add a single line in your build.gradle file. Perform a build of your application to receive a newly built APK.

android {
    ...
    buildToolsRevision '21.1.1'
    defaultConfig {
      // Enable the experimental Jack build tools.
      useJack = true
    }
    ...
}

If you want to build your app with both toolchains, Product Flavors are a great way to do this. Your build.gradle file might look something like the snippet below.

android {
    ...
    productFlavors {
        dev {
            ...
        }
        experimental {
            useJack = true
        }
        prod {
            ...
        }
    }
    ...
}

How do I configure my build?

We are making the transition to Jack as smooth as possible by supporting minification (shrinking and/or obfuscation), as well as repackaging (i.e. similar to tools like jarjar), while using the same input files as you are used to. Minification is available in the Gradle plugin immediately and repackaging will follow. You should continue to use the “minifyEnabled true” directive to reduce the size of your app among all other optimizations you would normally use. There are more details on our reference page (linked below) regarding the level of support for each type of optimization. We encourage you to provide feedback there if your current configuration isn’t supported.

Give us your feedback

We are attempting to make the toolchain as easy to test out as possible and we’re looking for your help to fine tune it. Use the reference page to find known issues, file feature requests, and report bugs. Happy building!

Posted by Wayne Piekarski, Developer Advocate

We’re pleased to announce that the official Android Wear Watch Face API is now available for developers. Watch faces give users even more ways to express their personal style, while creating an opportunity for developers to customize the most prominent UI feature of the watches. Watch faces have been the most requested feature from users and developers alike, and we can’t wait to see what you build for them.

An Introduction to Watch Faces for Android Wear by Timothy Jordan

Design and development

To get started, first learn about Designing Watch Faces, and then check out the Creating Watch Faces training class. The WatchFace Sample available online and in the Android Studio samples manager also provides a number of different examples to help you jump right in. For a quick overview, you can also watch the Watch Faces for Android Wear DevByte video above.

Watch faces are services that run from your wearable app, so you can provide one or multiple watch faces with a single app install. You can also choose to have configuration activities on the phone or watch, for example to let a user change between 12 and 24-hour time, or to change the watch face’s background. You can use OpenGL to provide smooth graphics, and a background service to pull in useful data like weather and calendar events. Watch faces can be analog, or digital, or display the time in some new way that hasn’t been invented yet––it’s up to you.

Updates to existing devices

Over the next week, the latest release of Android Wear, based on Android 5.0 and implementing API 21, will roll out to users. All Android Wear devices will be updated to Android 5.0 via an over-the air (OTA) update. The update allows users to manage and configure watch faces in the Android Wear app on their phone, and install watch faces from Google Play. Any handheld device running Android 4.3 or later will continue to work with all Android Wear devices.

Upgrade your watch faces

Developers are incredibly resourceful and we’re impressed with the watch faces you were able to create without any documentation at all. If you’ve already built a watch face for Android Wear using an unofficial approach, you should migrate your apps to the official API. The official API ensures a consistent user experience across the platform, while giving you additional information and controls, such as letting you know when the watch enters ambient mode, allowing you to adjust the position of system UI elements, and more. Using the new API is also necessary for your app to be featured in the Watch Faces collection on Google Play.

Deployment of watch faces to Google Play

We recommend you update your apps on Google Play as soon as the Android Wear 5.0 API 21 OTA rollout is complete, which we’ll announce on the Android Wear Developers Google+ community. It’s important to wait until the OTA rollout is complete because a Watch Face requiring API 21 will not be visible on a watch running API 20. Once your user gets the OTA, then the watch face will become visible. If you want to immediately launch your updates during the OTA rollout, make sure you set minSdkVersion to 20 in your wearable app, otherwise the app will fail to install for pre-OTA users. Once the rollout is complete, please transition your existing watch faces to the new API by January 31, 2015, at which point we plan to remove support for watch faces that don’t use the official API.

Android Wear apps on Google Play

Starting today, you can submit any of your apps for designation as Android Wear apps on Google Play by following the Distributing to Android Wear guidelines. If your apps follow the criteria in the Wear App Quality checklist and are accepted as Wear apps on Play, it will be easier for Android Wear users to discover them. To opt-in for Android Wear review, visit the Pricing & Distribution section of the Google Play Developer Console.

In the few short months since we’ve launched Android Wear, developers have already written thousands of apps, taking advantage of custom notifications, voice actions, and fully native Android capabilities. Thanks to you, users have infinite ways to personalize their watches, choosing from six devices, a range of watch bands, and thousands of apps. With support for custom watch faces launching today, users will have even more choices in the future. These choices are at the heart of a rich Android Wear ecosystem and as we continue to open up core features of the platform to developers, we can’t wait to see what you build next.

Posted by Laurence Moroney, Developer Advocate

A constraint for some Android apps is the total number of methods that the underlying compiled .dex file can support. It’s limited by 16 bits, or 65,536 values.

When you include third-party libraries in your application, you will have all of their methods in your .dex file. Larger APIs, such as those included in Google Play services, will then begin eating into the limit very quickly.

You can learn more about this, and ways that you can work around it with the Android Studio 1.0 build system here.

Additionally, with Google Play services version 6.5 or later, it is possible for you to include Google Play services in your application using a number of smaller client libraries, so that only Google Play services APIs you use will get compiled into your .dex file, and therefore their methods won’t count towards your method limit.

Prior to version 6.5, you would typically have a line like this in your build.gradle file:

compile 'com.google.android.gms:play-services:6.5.87'

Starting with version 6.5, of Google Play services, you’ll be able to pick from a number of individual APIs, and you can see which ones have their own include files in the documentation. For example, if all you want to use is Maps, you would instead have:

compile 'com.google.android.gms:play-services-maps:6.5.87'

Note that this will transitively include the ‘base’ libraries, which are used across all APIs. You can include them independently with the following line:

compile 'com.google.android.gms:play-services-base:6.5.87'

The complete list of API names is below. More details can be found on the Android Developer site.

com.google.android.gms:play-services-base:6.5.87
com.google.android.gms:play-services-ads:6.5.87
com.google.android.gms:play-services-appindexing:6.5.87
com.google.android.gms:play-services-maps:6.5.87
com.google.android.gms:play-services-location:6.5.87
com.google.android.gms:play-services-fitness:6.5.87
com.google.android.gms:play-services-panorama:6.5.87
com.google.android.gms:play-services-drive:6.5.87
com.google.android.gms:play-services-games:6.5.87
com.google.android.gms:play-services-wallet:6.5.87
com.google.android.gms:play-services-identity:6.5.87
com.google.android.gms:play-services-cast:6.5.87
com.google.android.gms:play-services-plus:6.5.87
com.google.android.gms:play-services-appstate:6.5.87
com.google.android.gms:play-services-wearable:6.5.87
com.google.android.gms:play-services-all-wear:6.5.87


Note: At the time of writing, the correct version to use is 6.5.87. As this is a very granular number, it will get updated quite quickly, so be sure the check the latest version when you are coding. Often people will use a ‘+’ to denote versions, such as 6.5.+ to use the latest 6.5 build. However, it’s typically discouraged to use a ‘+’ as it can lead to inconsistencies.

Also, there are some changes to the names of the libraries that will impact you if you build applications for Android Wear. Previously you may have used play-services-wearable to include the entire Google Play services library for your wearable, and if you want to continue doing so, you should now use play-services-all-wear instead. You can continue to use play-services-wearable which will instead give you just the Wearable Data Layer API (see here). Should you do this, and you want to continue working with other Google Play services features, such as the Location APIs on your wearable, you would need to add play-services-location.

Posted by Leticia Lago, Google Play team

Over has taken a simple idea, adding text and artwork to photos, and turned it into a creative tool that enables anyone to easily and intuitively add a unique twist to any image.

The Over team recently decided to bring their successful app to Android. “We love unlocking human creativity and Android offers a massive opportunity for doing just that. It was a no-brainer,” says Aaron Marshall, Founder, CEO, and Designer at Over. “Moving to Cape Town was eye-opening in many ways. It made me experience first-hand how many people outside the US use Android. We see users in emerging markets using mobile devices as their primary device, and believe there is a lot of opportunity in providing them with creative tools for mobile.”

The entire team was new to the platform, and were quickly impressed by the ease of development and the power of the distribution tools in the Developer Console on Google Play.

In this video, the Over team talk about their experiences learning and working with Android.

Over engineer Johan Nell, who arrived with Java experience but hadn’t worked with Android, says that he and fellow engineer Herko Lategan “were able to get a working prototype out in the first week.”

Android plays a big part in Over living up to its mantra of “go big, and go home”. As Aaron explains, “we don’t think you should be sacrificing your family to create wealth, or add value, or change the world. Being able to experiment and iterate quickly is crucial in helping us achieve this goal.”

To learn about starting a successful business with Android, be sure to check out these resources:

• The Secrets to App Success on Google Play [ebook] — a detailed playbook on the best practices and tools you can use to maximize the reach, retention, and revenue of your new app.
• Getting Started [training] — check out this comprehensive learning resource that takes you from first principles through to the most powerful Android APIs.

By Jamal Eason, Product Manager, Android

Today we are excited to introduce Android Studio 1.0. Android Studio is the official Integrated Development Environment (IDE) from the Android team. It is built on the popular IntelliJ IDEA (Community Edition) Java IDE.

We first released a preview of Android Studio at I/O last year. We value the on-going feedback from you, thanks! We are making Android Studio 1.0 available for download as a stable release on the Android Developer site.

Download Android Studio

If you are currently developing for Android or thinking about getting started, now is the time to download Android Studio 1.0 (or upgrade if you are using an earlier version). Similar to the Chrome release channels, Android Studio will continue to receive updates on four different release channels: Stable, Beta, Dev, and Canary. Canary builds are at the bleeding edge of development, while the stable release is fully tested. With this range of release channels you can choose how quickly you want to get the latest features for Android Studio.

Android Studio features

With the release of Android Studio, you have access to a new set of features to enable your development workflow. Some of the key features of Android Studio are listed below, but make sure to check out the Android Studio page for a full feature overview.

Startup experience

• First-run setup wizard — The getting started experience now installs the right Android SDK, sets up your development environment settings, and creates an optimized emulator for testing your app. Plus, we include a set of code templates to help you get started.
• 
• Sample Importing & templates — Android Studio includes wizards that enable you to start with new project templates or import Google code samples.
• 

Code and resource editing, user interface design

• Code Editing — Android Studio takes advantage of all the intelligent code editing capabilities of IntelliJ IDEA such as advanced code completion, refactoring, and code analysis.
• 
• Internationalization string editing — Manage string translations of your app in Android Studio.
• 
• User interface design — Edit and preview your Android Layouts across multiple screen sizes, languages, and even API versions.
• 

Performance analysis

• Memory monitor — View the memory usage of your app over time to help find ways to improve the performance of your app.
• 
  

Unified build system

• Android Studio uses a Gradle-based build system that provides a lot of flexibility and extensibility, as well as the ability to build from within and outside of the IDE. This unified build system decouples the build from Studio itself, meaning that Studio updates never impact the output of your build.
• Some of the key features of the build systems are: build variant support to better handle different build types (debug vs. release), or different versions of the same app (paid vs. free), multi-apks handling through splits, multi-dex support, and dependency management for 3rd party libraries.

Instant access to Google Cloud Services

• Android Studio even enables an easy way to add Google Cloud Backends & Endpoints to your app, as well as Google Cloud Messaging (find out more).
• 
  

Time to migrate & update

If you are an Eclipse user, check out our migration steps or you can just import your projects right into Android Studio with the import wizard, shown below:

If you were using one of the early versions of Android Studio, you should also upgrade to version 1.0 since we have added a host of new features and have addressed many bugs.

We have also released version 1.0 of the Gradle plugin with a file format that is now stable. The communication between Android Studio and the Gradle plugin is now stable, so updating one will not require updating the other. Check the technical release notes for additional tips for updating your previous Android Studio projects.

Give us your feedback

We are always seeking to bring you the best Android development experience. We already have plans to add features ranging from improved testing and better support for game development, but we want to know how you work and what capabilities you’d like to have for your Android development.

Please take a moment to complete a short survey (less than 5 minutes). Your responses will help shape the next set of features offered in Android Studio.

Questions?

We develop Android Studio and the corresponding tools in open source, so you can also file bugs via the public Android bug tracker and we will do our best to address your issues or questions. If you have specific questions or need help in your migration, feel free to connect with the Android developer tools team on our Google+ community page.

By Jamil Moledina, Games Strategic Partnerships Lead, Google Play

In the coming months, we’ll be seeing more media players, like the recently released Nexus Player, and TVs from partners with Android TV built-in hit the market. While there’s plenty of information available about the technical aspects of adapting your app or game to Android TV, it’s also useful to consider design changes to optimize for the living room. That way you can provide lasting engagement for existing fans as well as new players discovering your game in this new setting. Here are three things one developer did, and how you can do them too.

Infinite Dreams is an indie studio out of Poland, co-founded by hardcore game fans Tomasz Kostrzewski and Marek Wyszyński. With Sky Force 2014 TV, they brought their hit arcade style game to Android TV in a particularly clever way. The mobile-based version of Sky Force 2014 reimaged the 2004 classic by introducing stunning 3D visuals, and a free-to-download business model using in-app purchasing and competitive tournaments to increase engagement. In bringing Sky Force 2014 to TV, they found ways to factor in the play style, play sessions, and real-world social context of the living room, while paying homage to the title’s classic arcade heritage. As Wyszyński puts it, “We decided not to take any shortcuts, we wanted to make the game feel like it was designed to be played on TV.”

Orientation

For starters, Sky Force 2014 is played vertically on a smartphone or tablet, also known as portrait mode. In the game, you’re piloting a powerful fighter plane flying up the screen over a scrolling landscape, targeting waves of steampunk enemies coming down at you. You can see far enough up the screen, enabling you to plan your attacks and dodge enemies in advance.

When bringing the game to TV, the quickest approach would have been to preserve that vertical orientation of the gameplay, by pillarboxing the field of play.

With Sky Force 2014, Infinite Dreams considered their options, and decided to scale the gameplay horizontally, in landscape mode, and recompose the view and combat elements. You’re still aiming up the screen, but the world below and the enemies coming at you are filling out a much wider field of view. They also completely reworked the UI to be comfortably operated with a gamepad or simple remote. From Wyszyński’s point of view, “We really didn’t want to just add support for remote and gamepad on top of what we had because we felt it would not work very well.” This approach gives the play experience a much more immersive field of view, putting you right there in the middle of the action. More information on designing for landscape orientation can be found here.

Multiplayer

Like all mobile game developers building for the TV, Infinite Dreams had to figure out how to adapt touch input onto a controller. Sky Force 2014 TV accepts both remote control and gamepad controller input. Both are well-tuned, and fighter handling is natural and responsive, but Infinite Dreams didn’t stop there. They took the opportunity to add cooperative multiplayer functionality to take advantage of the wider field of view from a TV. In this way, they not only scaled the visuals of the game to the living room, but also factored in that it’s a living room where people play together. Given the extended lateral patterns of advancing enemies, multiplayer strategies emerge, like “divide and conquer,” or “I got your back” for players of different skill levels. More information about adding controller support to your Android game can be found here, handling controller actions here, and mapping each player’s paired controllers here.

Business Model

Infinite Dreams is also experimenting with monetization and extending play session length. The TV version replaces several $1.99 in-app purchases and timers with a try-before-you-buy model which charges $4.99 after playing the first 2 levels for free. We’ve seen this single purchase model prove successful with other arcade action games like Mediocre’s Smash Hit for smartphones and tablets, in which the purchase unlocks checkpoint saves. We’re also seeing strong arcade action games like Vector Unit’s Beach Buggy Racing and Ubisoft’s Hungry Shark Evolution retain their existing in-app purchase models for Android TV. More information on setting up your games for these varied business models can be found here. We’ll be tracking and sharing these variations in business models on Android TV, including variations in premium, as the Android TV platform grows.

Reflecting on the work involved in making these changes, Wyszyński says, “From a technical point of view the process was not really so difficult – it took us about a month of work to incorporate all of the features and we are very happy with the results.” Take a moment to check out Sky Force 2014 TV on a Nexus Player and the other games in the Android TV collection on Google Play, most of which made no design changes and still play well on a TV. Consider your own starting point, take a look at the Android TV section on our developer blog, and build the version of your game that would be most satisfying to players on the couch.

Posted by Leticia Lago, Google Play team

musiXmatch is an app that offers Android users the unique and powerful feature FloatingLyrics. FloatingLyrics pops up a floating window showing synched lyrics as users listen to tracks on their favorite player and music services. It’s achieved through a seamless integration with intents on the platform, something that’s technically possible only on Android.

As a result musiXmatch has seen “a dramatic increase in terms of engagement’, says founder Max Ciociola, “which has been two times more active users and even two times more the average time they spend in the app.”

The ability to deliver lyrics to a range of different devices — such as Chromecast, Android TV, and Android Wear — is creating opportunities for musiXmatch. It’s helping them turn their app into a smart companion for their users and getting them closer to their goal of reaching 100 million people.

In the following video, Max and Android engineer Sebastiano Gottardo talk about the unique capabilities that Android offers to musiXmatch:

To learn about achieving great user engagement and retention and reaching more users through different form factors, be sure to check out these resources:

• Convert installs to active users — Watch this video to hear from Matteo Vallone, Partner Development Manager for Google Play, about the best practices in engaging and retaining app users using intents, identity, context, and rich notifications as well as delivering a cross-platform user experience.
• Expanding to new form factors: Tablet, Wear & TV — Watch this panel discussion with Google experts talking about cross-platform opportunities and answering developer questions.

By Ellie Powers, product manager for Google Play

Google Play is the largest digital store for Android users to discover and purchase their favorite mobile app and games, and the ecosystem is continuing to grow globally. Over the past year, we’ve expanded the list of countries where app developers can sign up to be merchants on Google Play, totaling 60 countries, including Lebanon, Jordan, Oman, Pakistan, Puerto Rico, Qatar and Venezuela most recently.

As part of that continued effort, we’re excited to announce merchant support in China, enabling local developers to export and sell their apps to Google Play users in more than 130 countries. Chinese developers can now offer both free and paid applications through various monetization models, including in-app purchasing and subscriptions. For revenue generated on Google Play, developers will receive payment to their Chinese bank accounts via USD wire transfers.

If you develop Android apps in China and want to start distributing your apps to a global audience through Google Play, visit play.google.com/apps/publish and register as a developer. If you want to sell apps and in-app products, you’ll need to also sign up for a Google Wallet merchant account, which is available on the “Revenue” page in the Google Play Developer Console. After you’ve uploaded your apps, you can set prices in the Developer Console and later receive reports on your revenue. You’ll receive your developer payouts via wire transfer. For more details, please visit our developer help center.

We look forward to continuing to roll out Google Play support to developers in many more countries around the world.

中国开发者可以向全球130个国家的Google Play用户提供付费应用啦

发表者：Ellie Powers, Google Play产品经理

Google Play是一个可让Android用户发现和购买他们喜爱的移动应用程序和游戏的全球最大的应用商店，这个生态系统在全球迅速成长。过去一年中，我们已经扩展到60个国家，让应用程序开发人员可以注册成为 Google Play的商家，其中新近支持的国家包括黎巴嫩、约旦、阿曼、巴基斯坦、波多黎各、卡塔尔和委内瑞拉。

作为持续改进 Google Play努力的一部分，我们很高兴地宣布在中国增加了对商家的支持，让中国的开发者能售卖应用程序到130个国家的 Google Play 用户。中国的开发者现在可以提供通过各种盈利模式的免费和付费应用，包括应用内购买和订阅。在 Google Play 产生的营收将通过美元电汇的方式支付给开发者的中国的银行账户。

如果你在中国开发Android应用程序，并希望通过 Google Play 把应用程序推广到全球，请登录play.google.com/apps/publish 并建立你的 Google Play 开发者账户。如果你想售卖付费的应用程序和应用程序内的产品，则需要再注册一个Google 电子钱包商家帐户，通过Google Play开发者控制台里的”营收”页面进行设置。上传应用程序后，你可以通过开发者控制台设定价格，之后就可以收到营收报告，你将会通过电汇的方式获得收入。

我们将继续增加更多 Google Play 商家支持的国家，敬请关注。

更多详情，请访问我们的开发者帮助中心。

Posted by Alex Ames, Fun Propulsion Labs at Google*

We’re pleased to announce Pie Noon, a simple game created to demonstrate multi-player support on the Nexus Player, an Android TV device. Pie Noon is an open source, cross-platform game written in C++ which supports:

• Up to 4 players using Bluetooth controllers.
• Touch controls.
• Google Play Games Services sign-in and leaderboards.
• Other Android devices (you can play on your phone or tablet in single-player mode, or against human adversaries using Bluetooth controllers).

Pie Noon serves as a demonstration of how to use the SDL library in Android games as well as Google technologies like Flatbuffers, Mathfu, fplutil, and WebP.

• Flatbuffers provides efficient serialization of the data loaded at run time for quick loading times. (Examples: schema files and loading compiled Flatbuffers)
• Mathfu drives the rendering code, particle effects, scene layout, and more, allowing for efficient mathematical operations optimized with SIMD. (Example: particle system)
• fplutil streamlines the build process for Android, making iteration faster and easier. Our Android build script makes use of it to easily compile and run on on Android devices.
• WebP compresses image assets more efficiently than jpg or png file formats, allowing for smaller APK sizes.

You can download the game in the Play Store and the latest open source release from our GitHub page. We invite you to learn from the code to see how you can implement these libraries and utilities in your own Android games. Take advantage of our discussion list if you have any questions, and don’t forget to throw a few pies while you’re at it!

* Fun Propulsion Labs is a team within Google that’s dedicated to advancing gaming on Android and other platforms.

Posted by Daniel Holle, Product Manager

At Google I/O back in June, we provided a preview of Android Auto. Today, we’re excited to announce the availability of our first APIs for building Auto-enabled apps for audio and messaging. Android apps can now be extended to the car in a way that is optimized for the driving experience.

For users, this means they simply connect their Android handheld to a compatible vehicle and begin utilizing a car-optimized Android experience that works with the car’s head unit display, steering wheel buttons, and more. For developers, the APIs and UX guidelines make it easy to provide a simple way for users to get the information they need while on the road. As an added bonus, the Android Auto APIs let developers easily extend their existing apps targeting Android 5.0 (API level 21) or higher to work in the car without having to worry about vehicle-specific hardware differences. This gives developers wide reach across manufacturers, model and regions, by just developing with one set of APIs and UX standards.

There are two use cases that Android Auto supports today:

• Audio apps that expose content for users to browse and allow audio playback from the car, such as music, podcasts, news, etc.
• Messaging apps that receive incoming notifications, read messages aloud, and send replies via voice from the car.

To help you get started with Android Auto, check out our Getting Started guide. It’s important to note that while the APIs are available today, apps extended with Android Auto cannot be published quite yet. More app categories will be supported in the future, providing more opportunities for developers and drivers of Android Auto. We encourage you to join the Android Auto Developers Google+ community to stay up-to-date on the latest news and timelines.

We’ve already started working with partners to develop experiences for Android Auto: iHeartRadio, Joyride, Kik, MLB.com, NPR, Pandora, PocketCasts, Songza, SoundCloud, Spotify, Stitcher, TextMe, textPlus, TuneIn, Umano, and WhatsApp. If you happen to be in the Los Angeles area, stop by the LA Auto Show through November 30 and visit us in the Hyundai booth to take Android Auto and an app or two for a test drive.