CODEWITHSUNDEEP
javajavafxdata-bindinglabel
Lisa
Lisa

Reputation: 49

Change Label depending on boolean JavaFX

I am super new to JavaFX and for my checkers game I want to display who's turn it is above my board. I have read through multiple very similar questions, but it doesn't seem to get me where I want to go. I hope you can help me!

I have a FXML file with the following code: 

<HBox fx:id="topBox" alignment="TOP_CENTER" prefHeight="45.0" prefWidth="200.0" spacing="10.0" BorderPane.alignment="CENTER" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SampleController">
     <children>
        <Label fx:id="labelTurn" text="test" />
        <Button fx:id="buttonResign" alignment="CENTER" mnemonicParsing="false" onAction="#doResign" prefHeight="25.0" prefWidth="80.0" text="Resign" />
     </children>
  </HBox>

In my main: 

public class Main extends Application {

    Checkers content = new Checkers();
    BorderPane border = new BorderPane(); 

    @Override
    public void start(Stage primaryStage) throws Exception {
        try {
            border.setTop(FXMLLoader.load(getClass().getResource("Sample.fxml")));
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        border.setCenter(createContent());
        Scene scene = new Scene(border);
        primaryStage.setTitle("Checkers from main");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

My controller:

public class SampleController {
    @FXML
    private Label labelTurn;

    @FXML
    private HBox topBox;

    @FXML
    private Button buttonResign;

    private Checkers content = new Checkers();

    @FXML
    void doResign(ActionEvent event) {
        content.resign();
        // System.exit(0); //TODO eine tatsächliche Methode eingeben!!

    }

    public void setLabelTurn(Label labelTurn) {
        this.labelTurn = labelTurn;

        String setLabelText() {
        String s = " ";
        if (content.getWhiteTurnPropValue()) {
            labelTurn.setText("White, it is your turn.");
            s = "White, it is your turn.";
            return s;
        } else {
            labelTurn.setText("Black, it is your turn.");
            s = "Black, it is your turn.";
            return s;
        }
    }
    @FXML
    void initialize() {
        assert buttonResign != null : "fx:id=\"buttonResign\" was not injected: check your FXML file 'Sample.fxml'.";
        assert topBox != null : "fx:id=\"topBox\" was not injected: check your FXML file 'Sample.fxml'.";
        assert labelTurn != null : "fx:id=\"labelTurn\" was not injected: check your FXML file 'Sample.fxml'.";
        labelTurn.textProperty().setValue(setLabelText());
    }
}

My game data has a BooleanProperty to show who's turn it is. It gets changed after every successful move.

BooleanProperty whiteTurnProp = new SimpleBooleanProperty(true);

public BooleanProperty getWhiteTurnProp() {
    return whiteTurnProp;
}

public void setWhiteTurnPropValue(Boolean whiteTurn) {
    this.whiteTurnProp.setValue(whiteTurn);
}

public boolean getWhiteTurnPropValue() {
    return this.whiteTurnProp.getValue();
}

As far as I have understood, I need to bind the Label to the value, which I have done in the initialize method. But when I play and the value in my game class changed, the label stays the same. How do I update the label? I think I need to add a change listener to something, but I dont know how to do that and more specifically WHERE.

Thank you so much for your help! I shortened my code a bit and hope it is still not too long.

Best, Lisa

Upvotes: 4

Views: 1848

Answers (1)

DVarga
DVarga

Reputation: 21799

In initialize: labelTurn.textProperty().setValue(setLabelText()); is not a binding, it is a simple set on the property. A really strange one as setLabelText() sets the text of the Label and also return the string which was set, which value is used again to the text of the Label.

You could create a real binding instead:

labelTurn.textProperty().bind(Bindings.createStringBinding(() -> {
    String s = " ";
    if (content.getWhiteTurnProp().get())
        s = "White, it is your turn.";
     else
        s = "Black, it is your turn.";

    return s;
}, content.getWhiteTurnProp()));

Upvotes: 5

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