什么是语境的Android？ [英] What is Context in Android?
问题描述
在Android的程序，到底什么是上下文类又是什么用的？我读到它的开发者网站，但我无法理解清楚。
In Android programming, what exactly is a Context class and what is it used for? I read about it on the developer site, but I am unable to understand it clearly.
推荐答案
把它简单地说：
顾名思义，应用/对象的当前状态其上下文。它让新创建的对象明白什么已经持续。通常你调用它来获取有关您的程序（活动，封装/应用），另一部分信息。
As the name suggests, its the context of current state of the application/object. It lets newly created objects understand what has been going on. Typically you call it to get information regarding another part of your program (activity, package/application)
您可以通过调用获取上下文 getApplicationContext（），的getContext（）， getBaseContext（）或这（当在活动类）。
You can get the context by invoking getApplicationContext(), getContext(), getBaseContext() or this (when in the activity class).
情况下的典型应用：
-
创建新的对象： 创建新的观点，适配器，监听器：
Creating New objects: Creating new views, adapters, listeners:
TextView tv = new TextView(getContext());
ListAdapter adapter = new SimpleCursorAdapter(getApplicationContext(), ...);
访问标准公共资源： 像LAYOUT_INFLATER_SERVICE服务，共享preferences：
Accessing Standard Common Resources: Services like LAYOUT_INFLATER_SERVICE, SharedPreferences:
context.getSystemService(LAYOUT_INFLATER_SERVICE)
getApplicationContext().getSharedPreferences(*name*, *mode*);
访问组件含蓄： 对于内容提供商，广播，意图
Accessing Components Implicitly: Regarding content providers, broadcasts, intent
getApplicationContext().getContentResolver().query(uri, ...);
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