Android---Android 4.0 Unifies Tablets and Phones with New Features .

原文地址：http://www.infoq.com/news/2011/10/Android-4-Ice-Cream-Sandwich

Android 4.0 runs both on tablets and phones, having new features for UI, communication, sharing, media, connectivity, input types and enterprise.

Google released Android 3.0 (Honeycomb) in February 2011 but only for tablets, having a new “holographic” user interface that was not ready to be installed on smaller screen factor devices such as smartphones. But they said they would release a new version of the mobile OS that would run both on tablets and smartphones. Android 4.0 (Ice Cream Sandwich) which was recently announced at AsiaD does exactly that, and it is powering Galaxy Nexus, manufactured by Samsung, and supposed to appear on the market soon.

Android 4.0 includes the UI widgets and APIs that tablets with Android 3.x have:

UI: Fragments and content loaders, action bar, resizable home screen widgets, rich notifications, multi-selection drag&drop clipboard.

Graphics/Animation: Hardware-accelerated 2D graphics, property-based animation, 3D graphics.

Communication: HTTP Live streaming, support for Bluetooth A2DP and HSP devices, support for RTP (Real-time Transport Protocol), MTP/PTP(Media/Photo Transfer Protocol), and DRM (Digital Rights Management), accepting input from keyboard, mouse, gamepad, joystick.

There are new features and APIs in Ice Cream Sandwich, some of them being described by category below.

UI. A new GridLayout for faster layout and rendering. The TextureView allows manipulating of OpenGL ES rendering like it was a normal object, and this feature is appropriate for camera preview, decoded video, or game scenes. 2D drawings can be hardware accelerated now, making it possible to scale, rotate or apply other transformations to text in a visually appealing mode.

Communication and sharing. All applications can now share information, having the possibility to integrate contacts, profile data, status updates from various social networks and calendar events using the Social and Calendar APIs. Android Beam allows communication between applications running on NFC-enabled phones simply by touching the phones. The ShareActionProvider widget allows developers to add sharing capabilities to their applications.

Media. A new API based on Khronos OpenMAX AL 1.0.1 for streaming multimedia, offering more control over streamed content. Camera supports ZSL exposure, continuous focus, image zoom, capturing full-resolution snapshots while shooting videos, face detection and others.

New media effects for transforming images and videos and run on the GPU: adjust color levels and brightness, change backgrounds, sharpen, crop, rotate, add lens distortion, and others.

Support for WebP, VP8, HTTP Live streaming v.3, Matroska containers.

Connectivity. With WiFi Direct applications can communicate with other nearby phones without having to use an Internet connection or a hotspot. Bluetooth HDP (Health Device Profile) is now supported enabling communication with corresponding health devices and sensors.

Input types. Android 4.0 supports new stylus input events such as pressure, tilt and distance axes, and others. It differentiates between stylus, finger, mouse and eraser, and supports multiple buttons devices.

Enterprise. These can benefit from the VPN API, its associated secured storage and the built-in VPN client in order to access L2TP and IPsec networks. The Device Policy Manager can be used to remotely control Android devices, including disabling the camera when working in sensitive environments.

There are approximately 4% changes between the API Level 13 (Android 3.2) and 14 (Android 4.0) including 804 additions (fields, methods, classes, etc.), 370 changes and 45 removals. The API Differences Report shows 5 new packages.

The SDK Tools (revision 14), Support Package (r4) and ADT plug-in for Eclipse (r14) have been updated in order to support the Android 4.0 API.

Android4.0增加了许多新特性，包括UI、通信、共享、媒体、连接、输入类型和企业功能，可以同时跑在平板电脑和手机上。

在2011年2月google针对平板电脑发布了Android3.0（代号Honeycomb），拥有全新的“holographics”用户界面，但是还没准备安装在想智能手机这样小屏幕的设备上。不过他们表示说会发布一款新的移动操作系统，可以同时跑在平板电脑和智能手机上。Android4.0（代号Ice Creame Sandwich）最近这次发布，正是实现了他们的诺言。目前这款系统已运行在由三星制造的Galaxy Nexus上，估计不久就会上市。

Android4.0包含了平板电脑Android3.x所拥有的UI部件和API，例如：

UI：片段和内容加载器，动作条，可调整大小的主屏幕部件，形式丰富的通知，多选拖放剪切板。

图形和动画：硬件加速的2D图形，基于属性的动画，3D图形。

通信：HTTP实时流，支持蓝牙A2DP和HSP设备，支持RTP（实时传输协议），MTP / PTP（媒体/图片传输协议）和DRM（数字版权管理），接受输入从键盘，鼠标手柄，摇杆。

当然Ice Cream Sandwich还有些新特性和API，其中一些分类描述如下：

UI：新的GridLayout布局，有着更快的布局速度和渲染力度。TextureView允许OpenGL ES的渲染操作，就像一个正常的对象，此功能很适合于摄像头预览、解码后的视频或游戏场景。2D绘图现在可以硬件加速，从而使缩放、旋转或其他转换操作在炫目视觉模式下展现到文本上。

通信和共享：现在所有的应用都可以共享信息，例如整合联系人、个人资料数据，使用社交网络API和日历API，根据各种社交网络和日历事件更新状态。Android电波允许在启用了NFC功能的手机上进行应用程序间的通信。ShareActionProvider部件允许开发者为他们的应用添加共享的功能。

媒体：基于Khronos OpenMAX AL 1.0.1的多媒体流API，在流媒体内容方面提供了更多控制权。相机支持ZSL曝光，连续对焦，图像缩放，捕捉全分辨率的快照，在拍摄影片、人脸识别和其他应用中都有了全新的体验。

新媒体转换的图像和视频和在GPU上运行的效果：调整色彩和亮度，改变背景、锐化、裁剪、旋转、添加滤镜失真，等等。

支持WebP，VP8，HTTP实时流V.3，Matroska容器。

连接：直接使用WiFi的应用程序可以和附近其他手机进行通信，而无需使用互联网连接或热点。现在支持蓝牙的HDP（卫生设备配置文件）能够与相应的医疗设备和传感器的通信。

输入类型：Android4.0支持新的手写笔的输入事件，如压力、倾斜和距离轴和其他事件。它可以区分手写笔、手指、鼠标和橡皮擦，并支持多点触摸设备。

企业：这些可以从VPN API中收益，其相关的安全存储和内置VPN客户端便于访问L2TP和IPsec网络。设备策略管理器可用于远程控制Android设备，包括在敏感的环境中工作时禁用相机。

在API Level 13和API Level 14（Android4.0）之间有大约4%的变化，包括804项新增（字段、方法、类等等），370项变化和45处移除。API差异报告显示5个新增软件包。

SDK工具（修订版14）、支持包（修订版4）和ADT Eclipse插件（修订版14）已经更新，以便支持Android4.0API。