public Session(Context cntx) {
        // TODO Auto-generated constructor stub
        prefs = PreferenceManager.getDefaultSharedPreferences(cntx);
    }

public void setUserID(int userID) {
        prefs.edit().putInt("userID", userID).apply();
    }

public int getID() {
        int userID;

        return userID = prefs.getInt("userID",0);

    }

StringRequest stringRequest = new StringRequest(Request.Method.POST, server_url, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        builder.setTitle("Server Response");
                        builder.setMessage("Response :"+response);

                        session = new Session(getApplicationContext());
                        int responseInt = Integer.parseInt(response.trim());
                        session.setUserID(responseInt);

                        Intent myIntent = new Intent(LoginActivity.this, navActivity.class);
                        startActivity(myIntent);
                        finish();

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my_jars);
        session = new Session(getApplicationContext());
        userID = (EditText) findViewById(R.id.userID);
        builder = new AlertDialog.Builder(MyJars.this);
        userID.setText(session.getID());