Question

When I call the popBackStack like:

manager.popBackStack("mybackstack", FragmentManager.POP_BACK_STACK_INCLUSIVE);

will the memory retained by the fragments that belongs to “mybackstack” will be freed?

I have a FragmentActivity that manages a ListFragment. Every time I click on item, the FragmentActivity instantiates a new Fragment which shows some information about the item clicked and then shows a DialogFragment with a Bitmap (that I recycle when the dialog is dismissed). I put the android:configChanges="orientation" in the manifest and override onConfigurationChanged as necessary.

Answer 1

Yes, the memory retained by the fragments will be freed. From the documentation,

public static final int POP_BACK_STACK_INCLUSIVE

Flag for popBackStack(String, int) and popBackStack(int, int):
If set, and the name or ID of a back stack
entry has been supplied, then all matching entries will be consumed
until one that doesn’t match is found or the bottom of the stack is
reached. Otherwise, all entries up to but not including that entry
will be removed.

and,

public abstract void popBackStack (String name, int flags)

Pop the last fragment transition from the manager’s fragment back stack.
If there is nothing to pop, false is returned. This function is
asynchronous — it enqueues the request to pop, but the action will
not be performed until the application returns to its event loop.

Note, however, that there is no guarantee that this memory will be freed immediately.