Android, How to restart/refresh a fragment from FragmentActivty?

Question

In my FragmentActivity I have a fragment. This fragment loads data from server. I want we user clicks on refresh button then I call a method in fragment and do refreshing pr

Answer 1

Executing this

onRefreshSelected = (OnRefreshSelected) MainScreen.this;

you are assigning your activity in onRefreshSelected field, trying to cast it to your interface, but your activity doesn't implement the interface, that's why ClassCastException raised.

Instead use something like this

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
                case R.id.menu_refresh:
                    CategoryFragment fragment = (CategoryFragment) getFragmentManager()
                        .findFragmentById(R.id.category_fragment);
                    if (fragment != null) {
                        fragment.getData();
                    }
                    return true;
                default:
                    return super.onOptionsItemSelected(item);
    }

Your activity can call methods in the fragment by acquiring a reference to the Fragment from FragmentManager, using findFragmentById() or findFragmentByTag().