Android Xxxactivity and Getapplicationcontext () differences

From the touch of Android, everywhere can see the context of the figure, after viewing the source code you will find that it is only an abstract class, the implementation is implemented in Contextwrapper.

When you go to see the source of Android, you will find Activity,service and application are inherited from Contextwrapper, that is, they are the sub-class of the context, then we should give the context of the assignment?

A lot of times when you assign a value to a context in a acitivity, you pass it directly, This is the xxxactivity.this, that is, the context of xxxactivity, of course, when the beginning does not understand the time will be directly written Getapplicationcontext (), of course, the difference between the two is very obvious, Xxxactivity.this returns an instance of the current activity, Getapplicationcontext () returns an instance of application, with a much worse life cycle, application throughout the app, Life cycle of activity believe you are clear, so do not mess with, prevent memory leaks

1.dialog

dialog attached to the activity, so directly with the xxxactivity.this, when the activity disappears dialog also destroyed

2.activity

As we have said above, the direct use of Xxxactivity.this, the return is the current activity instance, the current activity is destroyed, together destroy

3.service,broadcastreceiver

Both are possible.

Summary: It is not recommended to use Getapplicationcontext (), which is related to UI operations, and generally uses the context associated with the activity, the rest of the operation, depending on the length of the life cycle of the existence of the choice

And I'm sorry, I'm not going to update the IM section yet, so let's look at this part of the camera and later update

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Android Xxxactivity and Getapplicationcontext () differences