来自MainActivity的NavDrawer片段中的setText

Question

我继续在setText方法上获取此空对象引用。与导航标头一起正常工作，但在片段中它一直崩溃。我尝试过这种方式，或使用Bundle传递字符串，但似乎没有用。

我应该如何测试或应该进行哪些更改？

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
    private DrawerLayout drawer;


    //NavHeader
    private TextView header_name, header_email;

    //SessionManager
    SessionManager sessionManager;

    //maps
    private static final String TAG = "MainActivity";
    private static final int ERROR_DIALOG_REQUEST = 9001;

    private static final String FINELOCATION = Manifest.permission.ACCESS_FINE_LOCATION;
    private static final String COURSELOCATION = Manifest.permission.ACCESS_COARSE_LOCATION;

    private Boolean mLocationPermissionsGranted = false;
    private static final int LOCATION_PERMISSION_REQUEST_CODE = 1234;

    private static final float DEFAULT_ZOOM = 15f;

    private FusedLocationProviderClient mFusedLocationProviderClient;

    private GoogleMap mMap;


    String pontopartida, pontochegada;

    private EditText ponto_partidaInput, ponto_chegadaInput;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //GET USER DATA
        sessionManager = new SessionManager(this);
        sessionManager.checkLogin();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        View headerView = navigationView.getHeaderView(0);

        header_name = (TextView) headerView.findViewById(R.id.header_name);
        header_email = (TextView) headerView.findViewById(R.id.header_email);



        HashMap<String, String> user = sessionManager.getUserDetail();
        String mName =  user.get(sessionManager.NAME);
        String mEmail = user.get(sessionManager.EMAIL);

        header_name.setText(mName);
        header_email.setText(mEmail);

        Log.d("Name: ", mName);
        Log.d("Email: ", mEmail);

        FragmentManager MyAccfrag = getSupportFragmentManager();

        MyAccountFragment fragment = (MyAccountFragment) MyAccfrag.findFragmentById(R.id.nav_myaccount);

        fragment.setText(mName, mEmail);

...

public class MyAccountFragment extends Fragment {


    private TextView account_name;
    private TextView account_email;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_myaccount, container, false);

        account_name = (TextView) view.findViewById(R.id.name_accountfrag);
        account_email = (TextView) view.findViewById(R.id.email_accountfrag);


        return view;
    }

    public void setText (String Name, String Email){

        account_name.setText(Name);
        account_email.setText(Email);
    }
}