Android fragment transaction listener

Question

I need to listen when a fragment transaction is performed, for example, when I replace a fragment with another, without call to addToBackStack(). FragmentManager class provides a addOnBackStackChangedListener callback, but when I perform a fragment replacement without call to addToBackStack, it is not executed.

Edit: the listen operation is performed in a class which only have access to the activity instance and its fragment manager.

For a library which performs some actions when a fragment is destroyed. — Victor Manuel Pineda Murcia, Oct 11 '16 at 10:51

score 1 · Answer 1 · answered Oct 11 '16 at 12:15

1

You can use Base class for all your fragments. Then you can override onDetach() method. For example

public class BaseFragment extends Fragment {

@Override
public void onDetach() {
   // run code that needed by your library. e.g.
    if (getActivity() != null && getActivity() instanceof MainActivity) {
    ((MainActivity)getActivity()).someMethodToDetectOnDetach();
    }
    super.onDetach();
}

And then extends your fragments from BaseFragment like this

public class MyFragment extends BaseFragment {
// .....
}

answered Oct 11 '16 at 12:15

Hank Moody

354
2
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The same behavior you can use in onAttach(Context context); method (maybe is will be even better) – Hank Moody Oct 11 '16 at 12:22
Yes, I could do that, but I'm building a library project and I don't want to force that kind of things, like using a base class. But I think there is no other ways to do it. – Victor Manuel Pineda Murcia Oct 11 '16 at 13:39

score 0 · Answer 2 · answered Oct 11 '16 at 10:57

0

You can use Fragment's onAttach() method.

answered Oct 11 '16 at 10:57

Jan Slominski

2,968
4
35
61

The listen operation for fragment transactions is performed in a class which only have access to an activity instance and its FragmentManager. I will edit my question to clarify. – Victor Manuel Pineda Murcia Oct 11 '16 at 10:59
Did you ever figure this out? I have just tried an onBackStackChange listener but it never gets called even after setting it with the FragmentManager. – John Glen Oct 02 '20 at 02:42

Android fragment transaction listener

2 Answers2

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