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毕业设计（论文）外文翻译
毕业论日目 基于Android手机通讯录的设计与实现
作者姓名
所学专业X称 计算机科学与技术
学 号
指导教师
2
2012年6月10日
Android Develote the Java objects for that part. Therefore, unlike applications on most other systems, Android applications don't have a single entry point for everything in the application (no main() function, for example). Rather, they have essential components that the system can instantiate and run as needed. There are four types of components:
Activities
An activity presents a visual user interface for one focused endeavor the user can undertake.
Each activity is given a default window to draw in. Typically, the window fills the screen, but it might be smaller than the screen and float on top of other windows. The visual content of the window is provided by a hierarchy of views — objects derived from the base View class. Each view controls a particular rectangular space within the window. Parent views contain and organize the layout of their children. Leaf views (those at the bottom of the hierarchy) draw in the rectangles they control and respond to user actions directed at that space. Thus, views are where the activity*s interaction with the user takes view hierarchy is placed within an activity's window by the () method. The content view is the View object at the root of the hierarchy.
4
Services
A service doesn't have a visual user interface, but rather runs in the background for an indefinite period of time. For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate something and provide the result to activities that need it. Each service extends the Service base class.
Broadcast receivers
A broadcast receiver is a component that does nothing but receive and react to broadcast announcements. Many broadcasts originate in system code — for example, announcements that the timezone has changed, that the battery is low, that a pictur