getApplicationContext()、getBasecontext()、getApplication() 区别

getApplicationContext() Application context is associated with the Applicaition and will always be the same throughout the life cycle.

getBasecontext() should not be used just use Context instead of it which is associated with the activity and could possible be destroyed when the activity is destroyed.

getApplication() is available to Activity and Services only. Although in current Android Activity and Service implementations, getApplication() and getApplicationContext() return the same object, there is no guarantee that this will always be the case (for example, in a specific vendor implementation). So if you want the Application class you registered in the Manifest, you should never callgetApplicationContext() and cast it to your application, because it may not be the application instance (which you obviously experienced with the test framework).

翻译一下就是

getApplicationContext() 返回应用的上下文，生命周期是整个应用，应用摧毁它才摧毁

Activity.this 的context 返回当前activity的上下文，与getApplication()的返回值相同，属于activity ，activity 摧毁他就摧毁。

getBaseContext() 返回由构造函数指定或setBaseContext()设置的上下文，有些回调函数里面应该使用getBaseContext(),而不是Activity.this 。