Android fragment manager fragment change listener

Question

When replacing a fragment using a FragmentManager is it possible to add a listener for when the event is completed?

So

myFragmentManager
            .beginTransaction()
            .replace(R.id.fragmentContainer, fragment, FRAGMENT_TAG)
            .commit()

can I add a listener to myFragmentManager so that I know when the fragment has been replaced?

Answer 1

FragmentManager (android.support.v4.app.FragmentManager) has a nice method called registerFragmentLifecycleCallbacks which helps register a FragmentManager.FragmentLifecycleCallbacks. This allows us to take actions during the fragment's life cycle. You can do something in onFragmentCreated() as you wish.

FragmentManager fragmentManager =  getSupportFragmentManager();
        fragmentManager.registerFragmentLifecycleCallbacks(new FragmentManager.FragmentLifecycleCallbacks() {
            @Override
            public void onFragmentPreAttached(FragmentManager fm, Fragment f, Context context) {
                super.onFragmentPreAttached(fm, f, context);
                Log.v("FragXX1", f.getTag());
            }

            @Override
            public void onFragmentAttached(FragmentManager fm, Fragment f, Context context) {
                super.onFragmentAttached(fm, f, context);
                Log.v("FragXX2", f.getTag());
            }

            @Override
            public void onFragmentCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
                super.onFragmentCreated(fm, f, savedInstanceState);
                Log.v("FragXX3", f.getTag());
            }

            @Override
            public void onFragmentActivityCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
                super.onFragmentActivityCreated(fm, f, savedInstanceState);
                Log.v("FragXX4", f.getTag());
            }

            @Override
            public void onFragmentViewCreated(FragmentManager fm, Fragment f, View v, Bundle savedInstanceState) {
                super.onFragmentViewCreated(fm, f, v, savedInstanceState);
                Log.v("FragXX5", f.getTag());
            }

            @Override
            public void onFragmentStarted(FragmentManager fm, Fragment f) {
                super.onFragmentStarted(fm, f);
                Log.v("FragXX6", f.getTag());
            }

            @Override
            public void onFragmentResumed(FragmentManager fm, Fragment f) {
                super.onFragmentResumed(fm, f);
                Log.v("FragXX7", f.getTag());
            }

            @Override
            public void onFragmentPaused(FragmentManager fm, Fragment f) {
                super.onFragmentPaused(fm, f);
                Log.v("FragXX8", f.getTag());
            }

            @Override
            public void onFragmentStopped(FragmentManager fm, Fragment f) {
                super.onFragmentStopped(fm, f);
                Log.v("FragXX9", f.getTag());
            }

            @Override
            public void onFragmentSaveInstanceState(FragmentManager fm, Fragment f, Bundle outState) {
                super.onFragmentSaveInstanceState(fm, f, outState);
                Log.v("FragXX10", f.getTag());
            }

            @Override
            public void onFragmentViewDestroyed(FragmentManager fm, Fragment f) {
                super.onFragmentViewDestroyed(fm, f);
                Log.v("FragXX11", f.getTag());
            }

            @Override
            public void onFragmentDestroyed(FragmentManager fm, Fragment f) {
                super.onFragmentDestroyed(fm, f);
                Log.v("FragXX12", f.getTag());
            }

            @Override
            public void onFragmentDetached(FragmentManager fm, Fragment f) {
                super.onFragmentDetached(fm, f);
                Log.v("FragXX13", f.getTag());
            }
        }, true);

        FragmentTransaction ft = fragmentManager.beginTransaction();
        ft.replace(R.id.container, new TradeFragment(), "trien");
        ft.commit();

Answer 2

Your new Fragment's onResume function is launched when the new Fragment is active. You can do what you want to do when the previous Fragment is replaced in it.