Getapplicationcontext and activity. This

The context obtained by getapplicationcontext is associated with the application, and the lifecycle is from application creation to destruction.

Activity. This extends context, and its lifecycle is from activity creation to destruction.

After figuring out the lifecycle, we can understand it.

For example, if a global database operation class uses context, getapplicationcontext is used instead of activity. This ensures that database operations are irrelevant to activity.

 

In addition, activity is related to Windows, while getapplicationcontext is irrelevant to Windows. Therefore, you must use activity. This when creating a dialog box. Otherwise, an error occurs.