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Android 中的 API 平台和系统映像有什么区别？

[英]What is the difference between API platform and system image in Android?

原文 2014-12-16 22:51:21 7 4 android

I am confused between the concept of "API platform" and "System Image" in Android.我对 Android 中的“API 平台”和“系统映像”的概念感到困惑。 What's the difference between them?它们之间有什么区别？

4 个解决方案

Android Developer Site says that Android 开发者网站说

The Android system images available through the Android SDK Manager contain code for the Android Linux kernel, the native libraries, the Dalvik VM, and the various Android packages (such as the Android framework and preinstalled applications) .通过 Android SDK 管理器提供的 Android系统映像包含 Android Linux 内核、本机库、Dalvik VM 和各种 Android 包（例如 Android 框架和预装应用程序）的代码。 The emulator provides dynamic binary translation of device machine code to the OS and processor architecture of your development machine.模拟器提供设备机器代码到开发机器的操作系统和处理器架构的动态二进制转换。

The Android platform provides a framework API that applications can use to interact with the underlying Android system . Android 平台提供了一个框架 API，应用程序可以使用该API 与底层 Android 系统进行交互。 The framework API consists of:框架 API 包括：

A core set of packages and classes一组核心包和类

A set of XML elements and attributes for declaring a manifest file一组用于声明清单文件的 XML 元素和属性

A set of XML elements and attributes for declaring and accessing resources一组用于声明和访问资源的 XML 元素和属性

A set of Intents一组意图

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.应用程序可以请求的一组权限，以及系统中包含的权限强制执行 Android 平台的每个后续版本都可以包含对其提供的 Android 应用程序框架 API 的更新。

API platform is for developing the application and it is specific to a particular API version. API 平台用于开发应用程序，它特定于特定的 API 版本。 System image is to be installed on the compatible device (or emulator) in order to run the application.系统映像将安装在兼容设备（或模拟器）上以运行应用程序。 It contains the kernel code and driver that are necessary to run the application.它包含运行应用程序所需的内核代码和驱动程序。 Usually platform release includes the system image.通常平台发布包括系统镜像。

The system image mainly refers to the operating system's code and UI, based on a specific Android distro/version;系统映像主要是指操作系统的代码和 UI，基于特定的 Android 发行版/版本； with or without certain addons;有或没有某些插件； translated for a specific assembly language/architecture.为特定的汇编语言/体系结构翻译。
EX: system-images;android-30;google_apis_playstore;x86例如：系统图像；android-30；google_apis_playstore；x86

The platform is the set of libraries needed to build an app.平台是构建应用程序所需的一组库。

Does it matter which platform you use for whatever android system your testing it on?无论您在什么 android 系统上测试它，您使用哪个平台都重要吗？

Well, unless you have a specific combo you're looking for, you want to try to update your apps to the latest platform, and test them on all the different version-addon-arch systems;好吧，除非您有正在寻找的特定组合，否则您想尝试将您的应用程序更新到最新平台，并在所有不同的 version-addon-arch 系统上测试它们； virtually or physically.虚拟或物理。

Also, Google APIs are different form platform APIS.此外，Google API 与平台 APIS 不同。 They represent the Android version of the Google APIs.它们代表 Google API 的 Android 版本。
Ex: AdMob replaces AdSense and is an "addon" to the Android platform APIs.例如：AdMob 取代了 AdSense，是 Android 平台 API 的“插件”。

Android system images are just versions of Android that you can run on a computer. Android 系统映像只是您可以在计算机上运行的 Android 版本。 So if you wanted to test the very latest stuff you could download an Android O system image and run it on the emulator to see what Android O is like.所以如果你想测试最新的东西，你可以下载一个 Android O 系统映像并在模拟器上运行它来看看 Android O 是什么样的。 Or if you wanted to test your app against Android Lollipop, you could download the Lollipop system image and run that.或者，如果您想针对 Android Lollipop 测试您的应用，您可以下载 Lollipop 系统映像并运行它。