Pass Data to other Javafx screens

Question

People who work with Javafx, I need a lot of help, I’m trying to pass data from one screen to another but I can’t.

In my project I log in with a user searching in the database. Each user has one id. I need, by the time he logs in, I can send this id to the main screen to be able to touch the other things with this id.

I have Login.Controller, login.fxml. login.tela, and the main screen the same thing, following the MVC standard.

In the code below I log in, at that time I wanted to send the id user to my main screen.

public void logar() {

        DAO<Usuarios> dao = new DAO<Usuarios>(Usuarios.class);
        List<Usuarios> users = dao.obterTodos();

        for (int i = 0; i < users.size(); i++) {

            if (txEmail.getText().equals(users.get(i).getEmail()) && txSenha.getText().equals(users.get(i).getSenha())) {
                idUsu = users.get(i).getId();//consigo guardar o id nessa varivel que criei
                Principal p = new Principal();
            
                i = users.size();
                fechar();
                try {
                    p.start(new Stage());
                    
                    Alert alert = new Alert(AlertType.CONFIRMATION);alert.setTitle(idUsu.toString());
                    alert.show();//fiz um teste de alerte pra ver se realmente pegava o id na variavel que criei
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
}

Answer 1

I’d give you two choices

1st Make these attributes static so you can use it in which part of the code.

2nd You must not create a public method in the controller class that receives this data from the Start Screen (or any screen you want).