Android, back button deallocates Activity memory?

Question

I made a simple app to test the memory of Android. It has two Activities, A and B. A is a simple Activity with a button that starts B. B consists of a pretty big image (jpg, 1024x768 pixel in mdpi)

When I monitor this process using DDMS, heap goes up as expected when moving from A to B. When I press (hardware, or software using super.onBackPressed()) button on B and end up in A again, the heap does not shrink again, even after calling garbage collection. Is this expected? Will the memory taken up by B ever be released during the lifetime of the process?

Answer 1

onBackPressed() just pop your B Activity from the BackStack then your Activity is no longer visible(onStop() called)to you, but it's process have'nt been killed untill the Os need it's memory