JavaFX: Initialize RadioButton selection status

Question

I need to save the selection status of multiple RadioButtons, so I can see which RadioButton is selected, when I go back to the scene later on. It's not about the userData, it's about to see whether it's selected. Right now I know how to make it work but with a lot of messy copy & paste. Something like this for every ToggleGroup:

@FXML private RadioButton rb1;
@FXML private RadioButton rb2;

public static int[] status = new int[600];

// to save it
if (rb1.getSelect(true)){
 status[0] = 1;
} else {
 status[0] = 0;
} 

// to load it
if (status[0] == 1){
 rb1.setSelected(true);
} else {
 rb2.setSelected(true);
} 

The problem is that I program a survey with more than 300 questions with binary answers. So I have more than 600 different RadioButtons. It'd take hours to implement it this way.

Is there any smart way to do it? I'm grateful for any advice. Thanks in advance!

Answer 1

Here is a SCVExample, that contains the simplest implementation based on my comment: It defines a model (Survey and Question) then binds the GUI to this model.

public class Radios extends Application {

    class Survey {
        private ObservableList<Question> questions = FXCollections.observableArrayList();

        public ObservableList<Question> getQuestions() {
            return questions;
        }
    }

    class Question {

        private StringProperty text = new SimpleStringProperty("");
        private BooleanProperty answer = new SimpleBooleanProperty(false);


        public Question(String text) {
            setText(text);
        }


        public boolean isAnswer() {
            return answer.get();
        }

        public BooleanProperty answerProperty() {
            return answer;
        }

        public void setAnswer(boolean answer) {
            this.answer.set(answer);
        }


        public String getText() {
            return text.get();
        }

        public StringProperty textProperty() {
            return text;
        }

        public void setText(String text) {
            this.text.set(text);
        }
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        // Model
        Survey survey = new Survey();
        for (int i = 0; i<300; i++) {
            Question question = new Question("Do you like number " + i + "?");
            question.answerProperty().addListener((obs, oldval,newval) -> {
                System.out.println("Question: " + question.getText() + " answer changed from " + oldval + " to " + newval);
            });
            survey.getQuestions().add(question);
        }

        // View
        VBox root = new VBox();
        root.setSpacing(10);

        for (Question question : survey.getQuestions()) {

            VBox vBox = new VBox();
            vBox.setSpacing(5);
            HBox answerHBox = new HBox();
            answerHBox.setSpacing(20);
            vBox.getChildren().addAll(new Label(question.getText()), answerHBox);

            RadioButton yes = new RadioButton("Yes");
            RadioButton no = new RadioButton("No");
            ToggleGroup toggleGroup = new ToggleGroup();

            yes.setToggleGroup(toggleGroup);
            no.setToggleGroup(toggleGroup);

            answerHBox.getChildren().addAll(yes, no);
            yes.setSelected(question.isAnswer());
            no.setSelected(!question.isAnswer());

            toggleGroup.selectedToggleProperty().addListener((observable, oldValue, newValue) -> {
                question.setAnswer(newValue.equals(yes));
            });


            root.getChildren().add(vBox);

        }

        Scene scene = new Scene(new ScrollPane(root), 500, 500);

        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

This will generate a survey like:

Console output:

Question: Do you like number 1? answer changed from false to true
Question: Do you like number 3? answer changed from false to true
Question: Do you like number 6? answer changed from false to true
Question: Do you like number 8? answer changed from false to true
Question: Do you like number 8? answer changed from true to false
Question: Do you like number 8? answer changed from false to true