Few hours ago Google released the first build of Android O ,here a list all the new stuff added and what has changed .
App background limits to improve battery life, performance
Building off work in Nougat, Android O places more automatic background limits on implicit broadcasts, background services, and location updates. The end result are apps that have minimal impact on user’s battery life and the device’s interactive performance.
High-quality Bluetooth audio, pro audio API, Bluetooth control for calls from third-party apps
To improve audio fidelity, Sony has made their LDAC codec available as part of Android O. Qualcomm’s aptX and aptX HD codes are also supported. Meanwhile, the new AAudio API is designed for apps that require high-performance, low-latency audio. Lastly, the ConnectionService APIs have been updated to allow calls from third-party apps to interface and be controlled by Bluetooth devices, like cars.
New notification design, grouping, and snoozing
For improved glanceability, notifications in Android O are better grouped, with developers being able to customize the background color. However, Google notes that this should only be for “ongoing tasks which are critical for a user to see at a glance.”
Under the hood, Android is introducing app-defined categories for notifications. For example, a news app would group notifications under various sections, like politics or sports. These notification channels let developers give users fine-grained control over different kinds of alerts, as well as the ability to quickly turn off specific categories by holding down in the notification shade.
Users can also snooze notifications to reappear at a later time. Notifications will reappear with the same level of importance they first appeared at.
Some OEMs, like Samsung, skin devices all the down to the shape of app icons. Android O now allows developers to create adaptive icons with different shapes that the system will automatically display based on a mask selected by the device. These icons can feature animation interaction system-wide, including in the launcher, shortcuts, Settings, sharing dialogs, and in the overview screen.
Improved keyboard navigation
Noting the rise of keyboard navigation due to Android apps on Chrome OS, Android O has more reliable, predictable models for what “arrow” and “tab” navigation will do.
Platform support for password manager apps
Similar to how Android has long supported third-party keyboards, users can now choose a default password manager app with new autofill APIs.
Wide-gamut color for apps
Developers of imaging apps can take advantage of newer devices that feature a wide-gamut color capable display.
Accessibility service can respond to directional swipes (up, down, left, and right) from a device’s fingerprint sensor. Notably, this is labeled as an accessibility feature so it’s unclear whether it can be used system-wide to scroll anywhere.
Setting App Completely Redisigned
Android O completely revamps the Settings app with a completely white background, top bar, and even icon. To activate developer options, users who previously set a device password have to enter it before being able to access the menu.
Redesigned App info page w/ settings for PiP and lockscreen badges
The app info page features a larger icons with applications like YouTube featuring an ‘Advanced’ option to enable/disable picture in picture. As we previously reported, Android has also gained support for notification badges on app icons. Settings are available under app info, but developers need to first enable support before this feature will work.
More System UI Tuner customizations
In Android O, the System UI Tuner receives a number of major additions. The lockscreen has long featured two shortcuts accessible by swiping left or right on the screen. Users can now customize with different actions or completely remove them.
Another change allows a variety of navigation bar customizations, including spacing, left/right leaning, and the ability to add extra buttons.
External sources for installing APKs
Android O changes the behavior of installing APKs that are not downloaded via the Play Store. Rather than a universal setting to allow installs from unknown sources, users must grant install access from the app that downloaded the third-party APK.