Call a current visible NavHostFragment's method from Activity

Issue

To achieve this task, I am currently using a FragmentListner interface, but I need to use create a static method to get the instance of the fragment. To avoid this approach of static way, I am thinking if there is any better way to do it. I need to get the current visible fragment instance on the Activity and based upon that I need to call a method of that fragment.

If it is not a NavHost fragment I am getting easily the instance of fragment like this below and can call any public method from it.

    Fragment fragment = getCurrentFragment();
    if (fragment instanceof MyFragment) {
                ((MyFragment) fragment).doFragmentOperation();
      }

    private Fragment getCurrentFragment() {
       return this.getSupportFragmentManager()
            .findFragmentById(R.id.framelayout);
      }

But I am able to know which fragment is visible by addOnDestinationChangedLisnter method like below

navController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
        @Override
        public void onDestinationChanged(@NonNull NavController controller, @NonNull NavDestination destination, @Nullable Bundle arguments) {
          
            switch (destination.getId()) {
                case R.id.navigation_x:
                    Toast.makeText(this, "X fragment is visible", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.navigation_y:
                    Toast.makeText(this, "Y fragment is visible", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.navigation_z:
                    Toast.makeText(this, "Z fragment is visible", Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    });

Here we can able to know the visible fragment by destination id, is there anything which can return us the visible fragment instance directly??

Solution

You can use the NavHostFragment to get the primaryNavigationFragment using its childFragmentManager.

val navHostFragment = supportFragmentManager.findFragmentById(R.id.your_nav_host_fragment_id) as NavHostFragment
val currentFragment = navHostFragment.childFragmentManager.primaryNavigationFragment

See if this works for you!

Answered By - Arpit Shukla