Android API 级别

英文翻译
Android API 级别(中文3800字,英文2600字)
当你开发你的Android 应用程序时，了解该平台API 变更管理的基本方法和概念是很有帮助的。同样的，知道API 级别标识以及该标识如何保障你的应用与实际硬件设备相兼容对于开发及后续的发布、维护都是有益的。本节内容告诉你API 级别的知识，以及它如何影响你开发和使用的应用。关于如何使用“以API 级别进行过滤”来使用API 参考手册，从本文末尾的文档过滤(Filtering the documentation)中可以得到更多信息。
API 级别是什么？
API 级别是一个整数值，它唯一标识了一个具体版本的Android 平台，及其框架的API 的版本。
Android 平台提供了一套框架API，使得应用程序可以与系统底层进行交互。该框架API 由以下模块组成：
    一组核心的包和类
    清单(manifest)文件的XML 元素和属性声明
    资源文件的XML 元素和属性声明及访问形式
    各类意图(Intents)
    应用程序可以请求的各类授权，以及系统中包含的授权执行
每个Android 平台的后续版本会包括它提供的更新的Android 应用程序框架的API。

英文原文
Android API Levels
As you develop your application on Android, it's useful to understand the platform's general approach to API change management. It's also important to understand the API Level identifier and the role it plays in ensuring your application's compatibility with devices on which it may be installed.
The sections below provide information about API Level and how it affects your applications.
For information about how to use the "Filter by API Level" control available in the API reference documentation, see Filtering the documentation at the end of this document.
What is API Level?
API Level is an integer value that uniquely identifies the framework API revision offered by a version of the Android platform.
The Android platform provides a framework API that applications can use to interact with the underlying Android system. The framework API consists of:
    A core set of packages and classes
    A set of XML elements and attributes for declaring a manifest file
    A set of XML elements and attributes for declaring and accessing resources
    A set of Intents
    A set of permissions that applications can request, as well as permission enforcements included in the system
Each successive version of the Android platform can include updates to the Android application framework API that it delivers.