Google I/O is a developer-centric conference, so it's perhaps no surprise that one of the leading topics at Wednesday's keynote event was new application programming interfaces, or APIs.
Hugo Barra, the vice president of Android product management, took the stage at Moscone Center to detail several new frameworks to soon be available for developers on Google's mobile platform. With these new Google Play services, developers can use the same APIs that Google takes advantage of in its own apps.
First up were three new location-based APIs. Fused Location combines data from a device's cellular radio, GPS, and Wi-Fi to provide more uniform location features in apps. In particular, Barra stressed, the API for these often very power-hungry features is exceptionally efficient--it uses less than 1 percent of battery per hour.
The second new location-based API is geofencing, a feature that will be familiar to users of iOS. A geofence allows you to set up a geographical area, then trigger events when users enter or leave it; apps can maintain up to 100 active geofences per app.
Finally, the Activity Recognition API harnesses the power of the device's accelerometer to track physical activity. Combined with machine learning technology, Activity Recognition can figure out whether you're currently traveling on foot, in a car, or even by bicycle. That's sure to be a popular addition for makers of fitness-related apps.
In addition to the location-based APIs, Barra also showed off a new cross-platform Google+ sign-in API. Log in to a website with your Google+ sign-in, and, if you have the corresponding app on your Android device--the demo used Google partner The Fancy--you are automatically logged in with your credentials.
Google's popular push notification system, which is currently moving about 17 billion messages per day, has also now been bundled into Google Play services, along with three new features of its own. Persistent connection support lets servers send more messages even faster. Upstream messages lets apps send data back to servers in addition to receiving data from servers. And, in a feature sure to inspire the envy of iOS users everywhere, a sync API should make short work of managing notifications: When you dismiss a notification on device, it's cleared on all of your devices.
In a shot at its rival in Cupertino, Google's Barra also announced that the company is launching Google Play game services, offering many of the features iOS users have in Game Center, along with additional features such as the ability to play cross-platform between Android devices and Web-based games. Unfortunately, the on-stage demo ran into a few hiccups as the Google employees were unable to get a multiplayer session to work.