想买几本android的书，参考了很久都说所有的书都没直接看官网文档来的快，想做个笔记，顺便看下渣的英语到底有多渣 。上班了也没时间去系统的学习进阶了，当成一种坚持吧。
Introduction to Android
Android provides a rich application framework that allows you to build innovative apps and games for mobile devices in a Java language environment. The documents listed in the left navigation provide details about how to build apps using Android's various APIs.If you're new to Android development, it's important that you understand the following fundamental concepts about the Android app framework:
Android提供了丰富的应用框架允许你去创造app和game在java运行环境的手机上，这个文档清单在左边导航栏提供了详细的关于如何用各个Api去组建一个app。如果你刚开始一个新android产品，能提高你对android app 应用框架的根本概念的理解。
Apps provide multiple entry points
Android apps are built as a combination of distinct components that can be invokedindividually. For instance, an individualactivityprovides a singlescreen for a user interface, and aserviceindependently performswork in the background.
From one component you can start another component using anintent. You can even starta component in a different app, such as an activity in a maps app to show an address. This modelprovides multiple entry points for a single app and allows any app to behave as a user's "default"for an action that other apps may invoke.
app 提供了大量的入口进入点
Android app 创建正如一个可以被不同组件可以单独调用的结合体，例如，一个单独的activity页面提供了一个对于用户接口单一的屏幕，并且一个在后台service服务独立运行平台。 你可以通过Inent从一个组件开启另外一个组件，你甚至能开启一个组件在不同的app，如一个地图app 的显示位置的activity页面。这个模块让一个单独的app提供了多入口并且允许任何一个app有用户默认的行为对于其他app可以调用的动作。
Apps adapt to different devices
Android provides an adaptive app framework that allows you to provide unique resources for different device configurations. For example, you can create different XML layout files for different screen sizes and the system determines which layout to apply based on the current device's screen size.
You can query the availability of device features at runtime if any app features require specific hardware such as a camera. If necessary, you can also declare features your app requires so app markets such as Google Play Store do not allow installation on devices that do not support that feature.
app 适配不同的设备
android提供了自适应应用框架去允许你提供了单独的资源对于不同配置的设备，例如，你可以创建不同的Xml布局文件对于不同的屏幕尺寸和系统决定哪个布局去应用基于正确设备尺寸。
你可以运行时查询设备的可用性如果所有app特征需要特别的硬件如摄像机，如果必须，你也能声明你的app需求特征所以app 市场如google play stroe 不允许安装在不支持特征的设备上。
