UINavigationController-like stacked fragment

nvc.java

package net.mootoh.tabexperiment;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public class NavigationControllerFragment extends Fragment {
    public static final String KEY_CLASS = "KEY_CLASS";
    public static final String KEY_ARGS_FOR_SUB_FRAGMENT = "KEY_ARGS_FOR_SUB_FRAGMENT";

    public NavigationControllerFragment() { }

    static NavigationControllerFragment newInstance(String rootFragmentClass, Bundle argsForRootFragment) {
        Bundle args = new Bundle();
        args.putString(KEY_CLASS, rootFragmentClass);
        args.putBundle(KEY_ARGS_FOR_SUB_FRAGMENT, argsForRootFragment);

        NavigationControllerFragment instance = new NavigationControllerFragment();
        instance.setArguments(args);
        return instance;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_navigation_controller, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        Bundle args = getArguments();
        String klass = args.getString(KEY_CLASS);
        Bundle argsForSubFragment = args.getBundle(KEY_ARGS_FOR_SUB_FRAGMENT);

        if (getChildFragmentManager().getBackStackEntryCount() > 0) // child fragments should be retained
            return;

        try {
            Class kklass = Class.forName(klass);
            Constructor ctor = kklass.getConstructor();
            Fragment subFragment = (Fragment) ctor.newInstance();
            subFragment.setArguments(argsForSubFragment);

            getChildFragmentManager()
                .beginTransaction()
                .add(R.id.container, subFragment)
                .addToBackStack(null)
                .commit();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (java.lang.InstantiationException e) {
            e.printStackTrace();
        }
    }

    public void push(Fragment fragment) {
        FragmentManager fm = getChildFragmentManager();
        fm.beginTransaction()
            .replace(R.id.container, fragment)
            .addToBackStack(null)
            .commit();
    }

    /**
     * @return true if popped, false otherwise.
     */
    public boolean pop() {
        FragmentManager fm = getChildFragmentManager();
        if (fm != null && fm.getBackStackEntryCount() > 1) {
            fm.popBackStackImmediate();
            return true;
        }
        return false;
    }
}