Question

I’m new to programming; go easy. 🙂

I have a simple program (for learning purposes) that won’t compile unless I make the two TextField objects public. I’m getting an error (ava.lang.IllegalAccessException: Class javafx.fxml.FXMLLoader$ValueElement can not access a member of class firstjavafxprogram.SampleController with modifiers “private”). And I just can’t for the life of figure out why those two have to public but Label can be private. Hope I post my code correctly:

package firstjavafxprogram;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;

public class SampleController implements Initializable {

    @FXML
    private Label label;
    public TextField txtVolts;
    public TextField txtAmps;

    @FXML
    private void handleButtonAction(ActionEvent event) {
        String labelMessage = getTheMessage();
        label.setText(labelMessage);
    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }  

   @FXML
    private String getTheMessage(){
        String enteredVolts = txtVolts.getText();
        int volts = Integer.parseInt(enteredVolts);

        String enteredAmps = txtAmps.getText();
        int amps = Integer.parseInt(enteredAmps);

        int watts = volts * amps;
        String msgString = "Watts: " + Integer.toString(watts);

        return msgString;
    }
}

Answer 1

Change

@FXML
private Label label;
public TextField txtVolts;
public TextField txtAmps;

To

@FXML
private Label label;
@FXML
private TextField txtVolts;
@FXML
private TextField txtAmps;

as per this example.