[翻译]安卓介绍之应用程序原理.doc

Introduction to Android
To learn how apps work, start with App Fundamentals.
To begin coding right away, read Building Your First App.
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:
,你应该要懂得接下来的安卓应用框架的基础概念.
Apps provide multiple entry points
Android apps are built as bination of ponents that can be invoked individually. For instance, an individual activity provides a single screen for a user interface, and a service independently performs work in the background.
From ponent you can start ponent using an intent. You can even start ponent in a different app, such an activity in a maps app to show an address. This model provides 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.
安卓提供了多个入口点
,一个独立的activity仅提供一个用户界面,,甚至可以启动另一个app中的组件,.
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 instal