谷歌发布Android N开发者预览版

今天早些时候，谷歌发布了 Android N 开发者预览版。

谷歌称：

We’re doing something a little different this year by releasing the preview early… really early. By releasing a “work in progress” build earlier in development, we have more time to incorporate developer feedback. Also, the earlier preview allows us to hand off the final N release to device makers this summer, so they can get their hands on the latest version of Android earlier than ever.

其中包括在“N”版本的主要特点和新的API，谷歌强调了几个项目，其中包括：

Multi-window - A new manifest attribute called android:resizableActivity is available for apps targeting N and beyond. If this attribute is set to true, your activity can be launched in split-screen modes on phones and tablets. You can also specify your activity's minimum allowable dimensions, preventing users from making the activity window smaller than that size. Lifecycle changes for multi-window are similar to switching from landscape to portrait mode: your activity can handle the configuration change itself, or it can allow the system to stop the activity and recreate it with the new dimensions. In addition, activities can also go into picture-in-picture mode on devices like TVs, and is a great feature for apps that play video; be sure to set android:supportsPictureInPicture to true to take advantage of this.

         Direct reply notifications: The RemoteInput notification API, which was originally added for Android Wear, now works in N for phones and tablets. Using the RemoteInput API enables users to reply to incoming message notifications quickly and conveniently, without leaving the notification shade. Learn more here.

        Bundled notifications - With N, you can use the Notification.Builder.setGroup() method to group notifications from the same app together - for example individual messages from a messaging app. Grouped notifications can be expanded into individual notifications by using a two-finger gesture or tapping the new expansion button. Learn more here.

        Efficiency - We launched Doze in Marshmallow to save battery when your device is stationary. In N, Doze additionally saves battery whenever the screen turns off. If you’ve already adapted your app for Doze, e.g. by using the GCM high priority message for urgent notifications, then you’re set; if not, here’s how to get started. Also, we’re continuing to invest in Project Svelte, an effort to reduce the memory needs of Android so that it can run on a much broader range of devices, in N by making background work more efficient {link to documentation}. If you use JobScheduler for background work, you’re already on the right track. If not, N is a good time to make that switch. And to help you out, we’re making JobScheduler even more capable, so now you can use {@link android.app.job.JobScheduler} to react to things like changes to content providers.

        Improved Java 8 language support - We’re excited to bring Java 8 language features to Android. With Android's Jack compiler, you can now use many popular Java 8 language features, including lambdas and more, on Android versions as far back as Gingerbread. The new features help reduce boilerplate code. For example, lambdas can replace anonymous inner classes when providing event listeners. Some Java 8 language features --like default and static methods, streams, and functional interfaces -- are also now available on N and above. With Jack, we’re looking forward to tracking the Java language more closely while maintaining backward compatibility.

Android N 开发者预览版将支持Nexus 6, Nexus 6P, Nexus 5X, Nexus Player, Nexus 9 and Pixel C。谷歌将提供$ 150折扣，给那些想购买体验Pixel C来帮助测试预览版的开发者。

谷歌一再强调，"for developers only and is not intended for daily use or consumer use"。谷歌也预计推出一款供消费体验的版本。

此外，谷歌也表示 "making it easier for you to try out N on your development devices with the new Android Beta Program. Starting today, you'll be able to update your Android devices to the Developer Preview of N and receive ongoing updates via OTA"。