JAVAFX How can I create a method for setting objects visible? - javafx

Question

I am new to Java and JavaFX so sorry if this question seems a bit obvious but it is doing my head in. I have tried googling solutions but haven't been able to find anything so far.
Basically I am trying to re-use some code in Java FX to hide / show some objects when a button is pressed. Rather than copy / paste the whole code again, I want to put it in a method (or something similar) that gets called on different occasions.
So here is a simple code example that I hope explains what I am trying to do:
package src;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class example extends Application
{
#Override
public void start(Stage stage)
{
Button b1 = new Button();
b1.setText("Show Label 1 Only");
Button b2 = new Button();
b2.setText("Show Label 2 Only");
Button b3 = new Button();
b3.setText("Show Label 2 and 3");
Label l1 = new Label();
l1.setText("Label 1");
Label l2 = new Label();
l2.setText("Label 2");
Label l3 = new Label();
l3.setText("Label 3");
b1.setOnAction(e ->
{
l1.setVisible(true);
l2.setVisible(false);
l3.setVisible(false);
});
b2.setOnAction(e ->
{
l1.setVisible(false);
l2.setVisible(true);
l3.setVisible(false);
});
b3.setOnAction(e ->
{
l1.setVisible(false);
l2.setVisible(true);
l3.setVisible(true);
});
VBox root = new VBox();
root.setSpacing(10);
root.setAlignment(Pos.CENTER);
l1.setVisible(false);
l2.setVisible(false);
l3.setVisible(false);
root.getChildren().addAll(b1, b2, b3, l1, l2, l3);
Scene scene = new Scene(root, 200, 200);
stage.setScene(scene);
stage.setTitle("Example");
stage.show();
}
public static void main(String[] args)
{
launch(args);
}
}
As you can see, the first 2 lines of the code for B2 and B3 are the same, so it would be nice if I could just put these lines in a method that gets called in both scenarios. This is in essence what i am trying to achieve.
Any guidance would be much appreciated. Like I said, I'm new to JAVA / JAVAFX so sorry if it seems like an obvious question.

Answer 1

One simple way is to make the labels instance variables and just to define a method taking a boolean for each one, indicating if it should be visible:
public class Example extends Application {
private Label l1;
private Label l2;
private Label l3;
private void labelVisibility(boolean l1Visible, boolean l2Visible, boolean l3Visible) {
l1.setVisible(l1Visible);
l2.setVisible(l2Visible);
l3.setVisible(l3Visible);
}
#Override
public void start(Stage stage) {
Button b1 = new Button();
b1.setText("Show Label 1 Only");
Button b2 = new Button();
b2.setText("Show Label 2 Only");
Button b3 = new Button();
b3.setText("Show Label 2 and 3");
l1 = new Label();
l1.setText("Label 1");
l2 = new Label();
l2.setText("Label 2");
l3 = new Label();
l3.setText("Label 3");
b1.setOnAction(e -> labelVisibility(true, false, false));
b2.setOnAction(e -> labelVisibility(false, true, false));
b3.setOnAction(e -> labelVisibility(false, true, true));
VBox root = new VBox();
root.setSpacing(10);
root.setAlignment(Pos.CENTER);
labelVisibility(false, false, false);
root.getChildren().addAll(b1, b2, b3, l1, l2, l3);
Scene scene = new Scene(root, 200, 200);
stage.setScene(scene);
stage.setTitle("Example");
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
If you don't want to expand the scope of the labels (and want a bit more generality), your method can take a list of all the labels, and a list of the ones you want visible:
public class Example extends Application {
private void labelVisibility(List<Node> allNodes, Node... visibleNodes) {
List<Node> visibleNodeList = Arrays.asList(visibleNodes);
for (Node node : allNodes) {
node.setVisible(visibleNodeList.contains(node));
}
}
#Override
public void start(Stage stage) {
Button b1 = new Button();
b1.setText("Show Label 1 Only");
Button b2 = new Button();
b2.setText("Show Label 2 Only");
Button b3 = new Button();
b3.setText("Show Label 2 and 3");
Label l1 = new Label();
l1.setText("Label 1");
Label l2 = new Label();
l2.setText("Label 2");
Label l3 = new Label();
l3.setText("Label 3");
List<Node> allLabels = List.of(l1, l2, l3);
b1.setOnAction(e -> labelVisibility(allLabels, l1));
b2.setOnAction(e -> labelVisibility(allLabels, l2));
b3.setOnAction(e -> labelVisibility(allLabels, l2, l3));
VBox root = new VBox();
root.setSpacing(10);
root.setAlignment(Pos.CENTER);
labelVisibility(allLabels);
root.getChildren().addAll(b1, b2, b3, l1, l2, l3);
Scene scene = new Scene(root, 200, 200);
stage.setScene(scene);
stage.setTitle("Example");
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}