Difference between getContext() , getApplicationContext() , getBaseContext()

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1. http://stackoverflow.com/questions/22966601/what-is-different-between-mainactivity-this-vs-getapplicationcontext/22967165#22967165

There are two types of Context:

Application context is associated with the application and will always be same throughout the life of application -- it does not change. So if you are using Toast, you can use application context or even activity context (both) because toast can be displayed from anywhere with in your application and is not attached to a specific window. But there are many exceptions, one exception is when you need to use or pass the activity context.

Activity context is associated with to the activity and can be destroyed if the activity is destroyed -- there may be multiple activities (more than likely) with a single application. And sometimes you absolutely need the activity context handle. For example, should you launch a new activity, you need to use activity context in its Intent so that the new launching activity is connected to the current activity in terms of activity stack. However, you may use application‘s context too to launch a new activity but then you need to set flag Intent.FLAG_ACTIVITY_NEW_TASK in intent to treat it as a new task.

Let‘s consider some cases:

MainActivity.this refers to the MainActivity context which extends Activity class but the base class (activity) also extends Context class, so it can be used to offer activity context.

getBaseContext() offers activity context.

getApplication() offers application context.

getApplicationContext() also offers application context.

For more information please check this link.

2. http://stackoverflow.com/questions/10641144/difference-between-getcontext-getapplicationcontext-getbasecontext-and/10641257#10641257

• View.getContext(): Returns the context the view is currently running in. Usually the currently active Activity.

• Activity.getApplicationContext(): Returns the context for the entire application (the process all the Activities are running inside of). Use this instead of the current Activity context if you need a context tied to the lifecycle of the entire application, not just the current Activity.

• ContextWrapper.getBaseContext(): If you need access to a Context from within another context, you use a ContextWrapper. The Context referred to from inside that ContextWrapper is accessed via getBaseContext().

Difference between getContext() , getApplicationContext() , getBaseContext()

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原文地址：http://www.cnblogs.com/veins/p/4500492.html