In which cases getApplicationContext() function is used

Question

I am following some tutorials for learning android but the problem is they do not contain all the details.

Specifically, it would be great if some light could be shed upon the use cases for getApplicationContext().

Answer 1

You can think of a Context as a handle to your application's resources (i.e. everything in the res folder) and to the Android runtime. Classes like Activity, Service, Application inherit from Context, among others.

Typically, you'll pass in the current Activity whenever a Context is required, since Activity inherits from Context.

You'll also find information about using getApplicationContext() instead of your activities when a Context is required. This usually is to prevent whatever code that needs the Context from unnecessarily holding a reference to your Activity, which in the worst case might preventing it from being garbage collected (passing in the Application isn't really a huge problem in that scenario, because it's expected to be around for a long time).

However, there are certain scenarios where an argument of a method is of type Context, but an Activity is actually required. Using startActivity() is one example of this I believe (correct me if I'm wrong).