Android O Developer Preview is finally out! Official introduction of new features

Posted by Dave Burke, VP of Engineering, Google

Since its initial launch in 2008, the Android project has thrived thanks to the great feedback from our vibrant ecosystem of app developers, device manufacturers, and users. Lately, we've been working hard to improve our engineering processes to make it easier and more open to share and collaborate with partners.

So I'm very excited to share with you the first developer preview of the next generation OS: Android O. The usual caveats apply: this release is very early in development, we have more features coming, and there's still a lot of work to do to ensure stability and performance. But it's getting started :)

We'll be releasing updated developer previews in the coming months, and we'll be doing a deep dive on all things Android at Google I/O in May. In the meantime, we'd love your feedback on trying out new features and testing your apps on the new OS.

What's new in O

Android O introduces a ton of new features and APIs for you to use in your apps. Here are a few of the new features you can try out in the first Developer Preview:

1. Background restrictions:

We started working on extending users' battery life and improving device performance in Nougat, and Android O places a heavy emphasis on this. To that end, we're adding additional automatic restrictions on what apps can run in the background in three main areas: implicit broadcasts, background services, and location updates. These changes will make it easier for you to create apps that have the least impact on your users' devices and batteries. Background restrictions represent an important change in Android, so we want every developer to understand them. For more information, see the documentation on Background execution limits and Background location limits.

2. Notification channels:

Android O also introduces notification channels, which are new categories of notification content defined by apps. With channels, developers can give users granular control over different kinds of notifications, allowing users to block or change the behavior of each channel individually, rather than managing all notifications for an app in a unified way.

Android O also adds new visuals and groupings to notifications, making it easier to see what's in a notification when you receive a message or look at the notification shade.

3. Autofill API:

Android users have long relied on various password managers to automatically fill in login details and repetitive information, making it easier for users to set up new apps or process transactions. Now we’re making this easier across the ecosystem by adding platform support for autofill. Users can choose an autofill app, similar to how they choose a keyboard app. Autofill apps can store and protect user data, such as addresses, usernames, and even passwords. For apps that want to handle autofill, we’re adding new APIs to implement autofill services.

4. PIP and new window display functions for handheld devices:

Picture-in-Picture (PIP) display is now available for phones and tablets, so users can continue watching a video while chatting or hailing a ride. As long as the system supports PiP mode, the app can put itself into PiP mode from the resumed or paused state, and you can specify the aspect ratio and a set of custom interactions (such as play/pause). Other new window display features include a new application overlay window for applications to use (instead of the system alert window), and multi-monitor support for launching Activities on remote displays.

5. Font resources in XML:

Fonts are now a fully supported resource type in Android O. Apps can now use fonts in XML layouts, and can also define font families in XML — declaring the font style and weight, along with the font file.

6. Adaptive Icons:

To help you better integrate with the device UI, you can now create adaptive icons that the system can display as different shapes based on the mask selected by the device. The system will also automatically interact with the icons and use them in the launcher, shortcuts, settings, share dialogs, and overview screens.

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Adaptive icons can be displayed in various shapes on different device models.

7. Wide color gamut display for applications:

Android developers of imaging apps can now take advantage of new devices with wide color gamut displays. To display wide color gamut images, apps need to enable a flag in their manifest (for each activity) and load bitmaps with an embedded wide color gamut profile (AdobeRGB, Pro Photo RGB, DCI-P3, etc.).

8. Connect:

For the highest audio fidelity, Android O now also supports high-quality Bluetooth audio codecs, such as the LDAC codec. We're also adding new Wi-Fi features, such as Wi-Fi Sense, formerly known as Neighbor Aware Networking (NAN). On devices with the appropriate hardware, apps and nearby devices can discover and communicate over Wi-Fi without relying on an internet access point. We're working with hardware partners to bring Wi-Fi Sense technology to devices as quickly as possible.

The Telecom framework is extending the ConnectionService API to enable third-party calling apps to integrate with the System UI and operate seamlessly with other audio apps. For example, apps can display calls and control them through different types of UIs, such as a car head unit.

9. Keyboard Navigation:

As Google Play apps appear on Chrome OS and other large form factor devices, we've seen a return to keyboard navigation in these apps. In Android O, we've worked hard to build a more reliable and predictable navigation model for both arrows and tabs to help developers and end users navigate.

10. AAudio API for professional audio:

AAudio is a new native API designed specifically for apps that require high-performance, low-latency audio. Apps using AAudio read and write data through the card information stream. In Developer Preview, we will release an early version of this new API to get your feedback.

11. WebView enhancements:

In Android Nougat, we introduced an optional multi-process mode for WebView, which moved web content processing to an isolated process. In Android O, we enabled multi-process mode by default and added an API so that your app can handle errors and crashes, thereby enhancing security and improving app stability. As a further security measure, you can now choose to receive your app's WebView object to verify URLs through Google Safe Browsing.

12. Java 8 Language API and Runtime Optimization:

Android now supports several new Java Language APIs, including the new java.time API. In addition, the Android Runtime is faster, up to 2x faster in some application benchmarks.

13. Partner Platform Contribution:

Hardware vendors and silicon semiconductor industry partners worked hard to fix Android platform bugs and provide many enhancements in version O. For example, Sony contributed more than 30 feature enhancements, including the LDAC codec and 250 bug fixes for Android O.

Just a few steps to get started

First, provide compatibility for your app so that users can seamlessly transition to Android O. Simply download a device system image or emulator system image, install your current app, and test it—it should work and look good, and handle the behavior changes correctly. After making all necessary updates, we recommend publishing to Google Play immediately without changing your app's target platform.

Building with Android O

When you're ready, dive into O to learn all the features your app can take advantage of. Visit the O Developer Preview site for details on the preview timeline, behavior changes, new APIs, and support resources:

developer.android.google.cn/preview

Plan how your app will support background restrictions and other changes. Try out some of the great new features in your app -- notification channels, PIP, adaptive icons, font resources in XML, automatic TextView resizing, and many others. To make it easier for you to explore the new APIs in Android O, we provide an API diff report online as well as the Android O API reference.

The latest Canary version of Android Studio 2.4 includes many new features to help you get started with Android O. You can download and set up the O preview SDK from inside Android Studio, and then use Android O's XML font resources and automatic TextView resizing in the Layout Editor. In the coming weeks, we will provide more Android O support, so stay tuned.

We have also released an alpha version of the 26.0.0 Support Library for you to try out. This version adds many new APIs and increases the minSdkversion to 14. For more information, check out the release notes:

developer.android.google.cn/topic/libraries/support-library/revisions.html

Preview Updates

The O Developer Preview includes an updated SDK with system images for testing on the official Android Emulator and on Nexus 5X, Nexus 6P, Nexus Player, Pixel, Pixel XL, and Pixel C devices. If you're building for wearables, there's also an emulator for testing Android Wear 2.0 on Android O.

We plan to update the preview system images and SDK regularly throughout the O Developer Preview period. This initial preview is for developers only and is not intended for daily or consumer use, so we are only making it available via manual download and flashing. Downloads and instructions are available here:

developer.android.google.cn/preview/download.html

As we get closer to a final product, we'll also invite consumers to try it out, and at that time, we'll also open up sign-ups through Android Beta. Stay tuned for details, but please note that Android Beta is not currently available for Android O.

Give us feedback

As always, your feedback is important, so please tell us what you think — the sooner we hear from you, the more likely we are to act on it. If you find an issue, please report it here. We've moved to a more robust tool, Issue Tracker, which is also used internally at Google to track bugs and feature requests during product development. We hope this product will be easier to use.