问Popbackstack完成OnBackPressed中的活动

EN

 public static final int CLIENT_LIST_FRAGMENT = 1;
 public static final int CLIENT_DETAILS_FRAGMENT = 2;
 private int currentFragment = 0;

if (savedInstanceState == null) {
            //On first run, start the list fragment
            if (currentFragment == 0) {
                ClientListFragment listFrag = new ClientListFragment();
                getSupportFragmentManager().beginTransaction()
                        .add(R.id.container_client, listFrag, Constants.CLIENT_LIST_FRAGMENT_TAG)
                        .commit();
                currentFragment = CLIENT_LIST_FRAGMENT;
            } else {
                switch (currentFragment) {
                    case CLIENT_LIST_FRAGMENT:
                        addListFragment();
                        break;
                    case CLIENT_DETAILS_FRAGMENT:
                        addDetailsFragment(0);
                        break;
                }
            }
        }

 private void addListFragment(){
        ClientDetailsFragment listFrag = new ClientDetailsFragment();
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.container_client, listFrag, Constants.CLIENT_LIST_FRAGMENT_TAG)
                .addToBackStack("details")
                .commit();
        currentFragment = CLIENT_LIST_FRAGMENT;
    }

    private void addDetailsFragment(long companyId){
        ClientDetailsFragment detailsFrag = ClientDetailsFragment.newInstance(companyId);
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.container_client, detailsFrag, Constants.CLIENT_DETAILS_TAG)
                .addToBackStack(null)
                .commit();
        currentFragment = CLIENT_DETAILS_FRAGMENT;

    }

@Override
    public void onBackPressed() {
        if (currentFragment == CLIENT_DETAILS_FRAGMENT){
            getSupportFragmentManager().popBackStackImmediate();
        }else {
            super.onBackPressed();
        }
    }