NavigationDrawer + Google Maps problem

Hi, I have a problem pressing an option in my navigationView (R.id.create_marker) I want to create a marker in my MapFragment but I can not do it, any suggestions?

public class MainActivity extends AppCompatActivity {

    private DrawerLayout drawerLayout;
    private NavigationView navigationView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setToolbar();
        drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        navigationView = (NavigationView) findViewById(R.id.navview);
        // Rotation phone cancel
        if(savedInstanceState == null) {
            setFragmentByDefault();
        }

        // Items menu
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                boolean fragmentTransaction = false;
                Fragment fragment = null;

                switch (item.getItemId()) {
                    case R.id.create_marker:
                        Toast.makeText(MainActivity.this, "Crear Marker", Toast.LENGTH_SHORT).show(); 
                        // Crear marcador y mostrarlo en el mapa
                        fragmentTransaction = true;
                        break;

                }

                if(fragmentTransaction) {
                    //getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit();
                    item.setChecked(true);
                    getSupportActionBar().setTitle(item.getTitle());
                    drawerLayout.closeDrawers();
                }
                return false;
            }
        });
    }

    private void setFragmentByDefault() {
        getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, new MapFragment()).commit();
    }
    private void setToolbar() {
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_home);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) { // open menu
            case android.R.id.home:
                drawerLayout.openDrawer(GravityCompat.START);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

This is the structure of my Project, the MapFragment works normally.