如何在按钮单击时从一个片段切换到另一个片段？

有一个基础Acrivity，里面有Fragment_Go和Button go_button，怎么点击这个按钮去Fragment_Train呢？在代码中，我在 OnCreate 和 OnClick 中编写了以下几行，应用程序启动时没有错误，但按下按钮时没有任何反应。活动代码：

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    Fragment_Go fgo;
    Fragment_Programs fprograms;
    Fragment_Settings fsettings;
    Fragment_Statistic fstatistic;
    Fragment_Uprajnenia fuprajnenia;
    Fragment_zameri fzameri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        fgo = new Fragment_Go();
        if (fgo != null) {
            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
            fragmentTransaction.add(R.id.container, fgo);
            fragmentTransaction.commit();
        }
        fprograms = new Fragment_Programs();
        fsettings = new Fragment_Settings();
        fstatistic = new Fragment_Statistic();
        fuprajnenia = new Fragment_Uprajnenia();
        fzameri = new Fragment_zameri();
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        int id = item.getItemId();

        FragmentTransaction ftrans = getFragmentManager().beginTransaction();

        if (id == R.id.nav_go) {
            ftrans.replace(R.id.container, fgo);

        } else if (id == R.id.nav_programs) {
            ftrans.replace(R.id.container, fprograms);

        }else if (id == R.id.nav_uprajnenia) {
            ftrans.replace(R.id.container, fuprajnenia);


        }else if (id == R.id.nav_statistic) {
            ftrans.replace(R.id.container, fstatistic);

        } else if (id == R.id.nav_zameri) {
            ftrans.replace(R.id.container, fzameri);

        } else if (id == R.id.nav_settings) {
            ftrans.replace(R.id.container, fsettings);

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }
        ftrans.commit();

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

第一个片段代码：

public class Fragment_Go extends Fragment implements View.OnClickListener {

    Fragment_Train f_train;

    @Override
    public void onClick(View view) {

        FragmentTransaction ftrans = getFragmentManager().beginTransaction();


        if (getId() == R.id.go_button) {
            ftrans.replace(R.id.container, f_train);

        }
        ftrans.commit();

    }

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public Fragment_Go() {
        // Required empty public constructor
    }
    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment Fragment_Go.
     */
    // TODO: Rename and change types and number of parameters
    public static Fragment_Go newInstance(String param1, String param2) {
        Fragment_Go fragment = new Fragment_Go();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
       View rootView = inflater.inflate(R.layout.fragment__go, container, false);
        Button go_button = (Button) rootView.findViewById(R.id.go_button);

        go_button.setOnClickListener(this);

        return rootView;
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }
        public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}