We Keep Coding

JavaFX: Multiple 'views', 'pages' or scenes - how to approach?

I am trying to build a dummy webshop with JavaFX. I deliberately do not use fxml, scenebuilder, maven or any other build tool. Just plain JavaFX, in order to really get to understand the basics.
However, I ran into a problem creating and navigating different 'pages'.
I have tried various creative solutions, like this one (is posting links allowed?), but none fully work for me, as I want every 'page', 'view' or scene in a seperate java class file, in order to keep everything structured and orderly.
I figured I'd make a Borderpane as a parent layout for every page
abstract class WindowBase extends BorderPane {
public abstract BorderPane render(App app);
public WindowBase() {
Label labelTop = new Label("Top box");
HBox topBox = new HBox();
topBox.setStyle("-fx-background-color: red;");
topBox.getChildren().addAll(labelTop);
Label labelLeft = new Label("Left box");
VBox leftBox = new VBox();
leftBox.setStyle("-fx-background-color: green;");
leftBox.getChildren().addAll(labelLeft);
Label labelRight = new Label("Right box");
VBox rightBox = new VBox();
rightBox.setStyle("-fx-background-color: blue;");
rightBox.getChildren().addAll(labelRight);
Label labelBottom = new Label("Bottom box");
HBox bottomBox = new HBox();
bottomBox.setStyle("-fx-background-color: yellow;");
bottomBox.getChildren().addAll(labelBottom);
this.setTop(topBox);
this.setLeft(leftBox);
this.setRight(rightBox);
this.setBottom(bottomBox);
}
}
and a child, the home page
public class Homepage extends WindowBase {
public BorderPane render(App app) {
Button button = new Button("Go to shopping cart");
button.setOnAction((event) -> app.toShoppingCart());
StackPane centerPane = new StackPane();
centerPane.getChildren().add(button);
this.setCenter(centerPane);
return this;
}
}
and lastly my App.java that runs everything
public class App extends Application{
private WindowBase view;
public void start(Stage stage) throws Exception {
view = new Homepage();
stage.setScene(new Scene(view.render(this)));
stage.setFullScreen(true);
stage.show();
}
public static void main(String[] args) throws Exception {
launch(args);
}
public void toHomepage() {
this.view = new Homepage();
}
public void toShoppingCart() {
this.view = new ShoppingCart();
}
}
I understand that I can't pass this (App) as an argument to view.render(), use the parameter within the method render and expect to be able to manipulate it, because it only creates a new instance of App as soon as it gets there. However, I see no other way either.
I tried placing the navigation buttons in the App class, in order to be able to manipulate view, but then I cannot call on the buttons from the subsequent views.
There must be a way to achieve what I want without writing the complete GUI in one file, right? Should I make my view static in stead, is that it?
Instead of BorderPanes I am of course also okay with using Scenes, whatever works.

I have figured out exactly the solution that I wanted. Posting it here for whoever encounters the same situation.
Class WindowBase
public class WindowBase {
public BorderPane getMainPane() {
Label labelTop = new Label("Top box");
HBox topBox = new HBox();
topBox.setStyle("-fx-background-color: red;");
topBox.getChildren().addAll(labelTop);
Label labelLeft = new Label("Left box");
VBox leftBox = new VBox();
leftBox.setStyle("-fx-background-color: green;");
leftBox.getChildren().addAll(labelLeft);
Label labelRight = new Label("Right box");
VBox rightBox = new VBox();
rightBox.setStyle("-fx-background-color: blue;");
rightBox.getChildren().addAll(labelRight);
Label labelBottom = new Label("Bottom box");
HBox bottomBox = new HBox();
bottomBox.setStyle("-fx-background-color: yellow;");
bottomBox.getChildren().addAll(labelBottom);
BorderPane borderPane = new BorderPane();
borderPane.setTop(topBox);
borderPane.setLeft(leftBox);
borderPane.setRight(rightBox);
borderPane.setBottom(bottomBox);
return borderPane;
}
}
Class Homepage
public class Homepage extends WindowBase {
public BorderPane render(Button toShoppingCart) {
Label label = new Label("This is the homepage.");
label.setStyle(
"-fx-font: normal bold 30px 'elephant'; -fx-text-fill: black; -fx-background-color: red;");
StackPane stackPane = new StackPane();
stackPane.getChildren().addAll(label);
BorderPane mainPane = getMainPane();
VBox leftBox = (VBox) mainPane.getLeft();
leftBox.getChildren().add(toShoppingCart);
//I do not understand why this works. I abstracted leftBox from mainPane, then added shoppingCart, but never added the abstracted
// leftBox back to the mainPane before returning it. This should not work, but it does. leftBox.getChildren().add(toShoppingCart)
// should have no effect.
//However, mainPane.getChildren().add(leftBox) throws an IllegalArgumentException about duplicate components, which is to be
// expected if the leftBox is already automatically added back to the mainPane.
mainPane.setCenter(stackPane);
return mainPane;
}
}
Class ShoppingCart
public class ShoppingCart extends WindowBase {
public ShoppingCart() {
super();
}
public BorderPane render(Button toHomepage) {
Label label = new Label("This is the shopping cart.");
label.setStyle(
"-fx-font: normal bold 30px 'elephant'; -fx-text-fill: black; -fx-background-color: red;");
StackPane centerPane = new StackPane();
centerPane.getChildren().add(label);
BorderPane mainPane = getMainPane();
VBox leftBox = (VBox) mainPane.getLeft();
leftBox.getChildren().add(toHomepage);
mainPane.setCenter(centerPane);
return mainPane;
}
}
Class App
public class App extends Application{
Scene scene;
#Override
public void start(Stage stage) throws Exception {
Homepage homePane = new Homepage();
Button toHomepage = new Button("Back to home page");
ShoppingCart shoppingPane = new ShoppingCart();
Button toShoppingCart = new Button("To shopping cart");
toHomepage.setOnAction(e -> scene.setRoot(homePane.render(toShoppingCart)));
toShoppingCart.setOnAction(e -> scene.setRoot(shoppingPane.render(toHomepage)));
scene = new Scene(homePane.render(toShoppingCart), 600, 400);
stage.setScene(scene);
stage.setFullScreen(true);
stage.show();
}
public static void main(String[] args) throws Exception {
launch(args);
}
}

How to set an action to occur on pressing of any keyboard key in JavaFX?

So I want to do a title Menu for a video game project for college. I want to display a message press any key to continue... then when the user pressed any key, including the mouse, a method would run to set the stage to the next menu.
I posted all the relevant code bellow but short version is:
BackgroundImangeDisplayPane extends display pane and adds a background image.
TitleCard extends BackgroundImangeDisplayPane adds a VBox and 2 labels to the VBox
I'm using public void start(Stage primaryStage) throws Exception as the main, I set the setOnActionxxx methods here
I have tried using the set on action method on root and Vbox and non of them work... when I click nothing happens... But when I resize the window The root.setOnActionXXX "activates".
If I write the setOnAction methods on the TitleCard class It kind of works but then I cant switch the stage.
I will post the code bellow as well an explanation of the Scene structure its not to complicated:
// this will be the borderpane for every scene it recives a backgund
//images that will be present in every menu
public BackgroundImangeDisplayPane() {
try {
stream = new FileInputStream(imagePath.toString());
Image image = new Image(stream);
ImageView imageView = new ImageView();
imageView.setImage(image);
imageView.setFitWidth(1920);
imageView.setPreserveRatio(true);
this.getChildren().add(imageView);
BackgroundSize backgoundSize = new BackgroundSize(AUTO, AUTO, true, true, true, true);
BackgroundImage backgroundImage = new BackgroundImage(image, NO_REPEAT, NO_REPEAT, CENTER, backgoundSize);
Background background = new Background(backgroundImage);
this.setBackground(background);
} catch (Exception e) {
}
}
//This extends `BackgroundImangeDisplayPane` and places on top of it a A Vbox with two lables: the title and "press any key to continue..."
// it then adds styles to the labels
public class TitleCard extends BackgroundImangeDisplayPane {
Label title = new Label("Boats & Docks"); // lable 1
Label subtitle = new Label("Press any key to continue ..."); label2
public TitleCard(){
super();
VBox vbox = new VBox();
vbox.getChildren().add(title);
vbox.getChildren().add(subtitle);
this.setCenter(vbox);
this.setAlignment(vbox, Pos.CENTER);
vbox.setAlignment(Pos.CENTER);
title.setFont(new Font(170)); // set to Label
title.setTextFill(Color.SNOW);
title.setEffect(new DropShadow());
subtitle.setFont( new Font (30));
}
}
...
//Works as the "main" in javaFX
private Stage primaryStage;
#Override
public void start(Stage primaryStage) throws Exception {
TitleCard root = new TitleCard();
/*BasicMenu menu = new BasicMenu(5);
menu.ButtonSetOnAction(0, e -> changeScene() );
BackgroundImangeWithCustomMenu background = new
BackgroundImangeWithCustomMenu(menu,50,50);
root.setCenter(background);*/
Button b = new Button();
b.setOnAction(e -> changeSceneToLoginMenu());
System.out.println(root.getChildren().get(1).getClass());
root.getChildren().get(1).setFocusTraversable(true);
root.getChildren().get(1).setOnMouseClicked(e -> changeSceneToLoginMenu());
root.getChildren().get(1).setOnKeyPressed(e -> changeSceneToLoginMenu());
root.getChildren().get(0).setOnMouseClicked(e -> changeSceneToLoginMenu());
root.getChildren().get(0).setOnKeyPressed(e -> changeSceneToLoginMenu());
/*
root.setOnMouseClicked(e -> changeSceneToLoginMenu());
root.setOnKeyReleased(e -> changeSceneToLoginMenu());
root.setOnKeyPressed(e -> changeSceneToLoginMenu());
*/
Scene scene = new Scene(root, 1280, 720);
primaryStage.setScene(scene);
primaryStage.show();
this.primaryStage = primaryStage;
}

As proposed by James in comments, when a key is pressed on the scene, navigate to the next scene (or replace the root in the current scene, and remove the key press handler).
scene.setOnKeyPressed(e -> navigateToNextScene());

I managed to find a very simple working solution but I don't fully undestand why it does work. I Noticed that if I set the handler in the same class the node was instanciated the handler would work fine But if I tried to get the node with a method to the main fuction via root.getChildren().get(1) and then cast it to the VBox element the handler would not work.
As a solution I made the VBox a field and wrote a setter method for the VBox event Handler in the TitleCard Class. This fixed the problem.
I marked the code added as solution code with comments
public class TitleCard extends BackgroundImangeDisplayPane {
Label title = new Label("Boats & Docks"); // lable 1
Label subtitle = new Label("Press any key to continue ..."); label2
VBox vbox = new VBox; // solution code
public TitleCard(){
super();
VBox vbox = new VBox();
vbox.getChildren().add(title);
vbox.getChildren().add(subtitle);
this.setCenter(vbox);
this.setAlignment(vbox, Pos.CENTER);
vbox.setAlignment(Pos.CENTER);
title.setFont(new Font(170)); // set to Label
title.setTextFill(Color.SNOW);
title.setEffect(new DropShadow());
subtitle.setFont( new Font (30));
}
// Solution Code
public void setVBoxHandler(EventHandler<? super MouseEvent> value){
vbox.setOnMouseClicked(value);
}
}
Then I set the handler in the start method:
public void start(Stage primaryStage) throws Exception {
TitleCard root = new TitleCard();
VBox vBox =(VBox) root.getChildren().get(1);
root.setVBoxHandler(e->changeSceneToLoginMenu() ); // solution Code
Scene scene = new Scene(root, 1280, 720);
primaryStage.setScene(scene);
primaryStage.show();
this.primaryStage = primaryStage;
}
public void changeSceneToLoginMenu() {
System.out.println("It finally worked");
Scene currentScene = new Scene(new Group(),100,100); // just a demo
primaryStage.setScene(currentScene);
}
notes: The type of value on the method setVBoxHandler(EventHandler<? super MouseEvent> value) will depend on the setOnXXX method used. For example I tested and this soultion also works for buttons just need to change the type to EventHandler<ActionEvent> value.
Some coments on the question posted links on "how to use handlers", this posts used anomimous classes. I belived This way is outdated. I used lambdas in the code the end result is the same but more redable code
Just for reference if future readers are using anomimous classes the solution would be the same just change the way you set up the handler:
// lambdas
setVBoxHandler( e -> System.out.println("Code run if mouse is clicked "));
// anomimous classes
setVBoxHandler(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event){
System.out.println("Code run if mouse is clicked ");
}
});

JavaFX - How to change scene using a scene from another class?

I have the following class which has a button.
public class GUI extends Application {
private BorderPane mainLayout = new BorderPane();
#Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Main Menu");
FlowPane layout = new FlowPane();
Button button = new Button("Click");
layout.getChildren().addAll(button);
mainLayout.setTop(layout);
Scene scene = new Scene(mainLayout, 600, 600);
primaryStage.setScene(scene);
primaryStage.show();
}
}
If I have another class with a scene, how can I update the GUI class to show the scene by pressing the button?

The preferred mechanism would probably be to get the stage dynamically from a trigger event, for example:
button.setOnAction(event -> {
Scene newScene = // ... commands which define the new scene.
Stage stage = ((Node) event.getTarget()).getScene().getStage();
// or alternatively, just:
// Stage stage = button.getScene().getStage();
stage.setScene(newScene);
});
An alternative is to provide a static accessor to the main stage in the Application.
Change your GUI class to add an accessor for the stage:
public class GUI extends Application {
private static Stage guiStage;
public static Stage getStage() {
return guiStage;
}
#Override
public void start(Stage primaryStage) {
guiStage = primaryStage;
// other app initialization logic . . .
}
}
In your class which needs to change the scene for the GUI stage to a new scene, invoke:
Scene newScene = // ... commands which define the new scene.
GUI.getStage().setScene(newScene);
Using a static accessor in this specific instance is generally OK, because you can only have a single Application instance launched for a given JVM execution. The only real drawback is that you have a coded dependency between the class creating your new scene and your Application class. But, for some application types, this won't matter.

JavaFX Same textarea with different Pane's

I have a project with maven, javafx and fxml. I have one main BorderPane, welcome.fxml, and Pane, ready.fxml.
My start method is;
#Override
public void start(Stage primaryStage) throws Exception {
try {
Pane root = (Pane) FXMLLoader.load(getClass().getResource("welcome.fxml"));
Scene scene = new Scene(root, 640, 480);
primaryStage.setScene(scene);
primaryStage.show();
} catch (Exception e) {
makeAlert(e, false);
}
}
Now, I have a button in my welcome.fxml, and I want to change my BorderPane's center with ready.fxml. Here is my button handler;
#FXML
private void buttonHandler() throws IOException, InterruptedException {
stage = (Stage) myButton.getScene().getWindow();
Pane sub = (Pane) FXMLLoader.load(getClass().getResource("../ready.fxml"));
BorderPane root = (BorderPane) FXMLLoader.load(getClass().getResource("../welcome.fxml"));
root.setCenter(sub);
//Scene scene = new Scene(root, 640, 480);
//stage.getScene().setRoot(root);
}
UPDATE: Here is my mistake,as #James_D noticed, I load welcome.fxml again in my controller and so, my whole Scene changes insted of only center.
The correct way should be;
stage = (Stage) brokerConnect.getScene().getWindow();
Pane center = (Pane) FXMLLoader.load(getClass().getResource("../ready.fxml"));
// FIXME: Get root like this
BorderPane root = (BorderPane) stage.getScene().getRoot();
root.setCenter(center);
EDITED: Java codes added.

You should update the center of the existing border pane, not create a new one and set the center of the new one.
All you need is to inject the border pane into the controller in the usual way. So add a fx:id to the root element of welcome.fxml:
<!-- imports, etc... -->
<BorderPane fx:id="root" fx:controller="..." xmlns:fx="..." ... >
<!-- ... -->
</BorderPane>
And then in the controller
public class Controller { /* or whatever name you have, again, you can't be bothered to post a MCVE */
#FXML
private BorderPane root ;
#FXML
private void buttonHandler() throws IOException {
Pane sub = (Pane) FXMLLoader.load(getClass().getResource("../ready.fxml"));
root.setCenter(sub);
}
// ...
}

Can you write two different Java FX scenes as two separate classes?

I'm a beginning Java programmer, finishing up the "Java 101" class at my local university. I'm also pushing myself to learn some extra topics on the side, including Java FX. I've worked through the Java FX tutorials on Oracle's website, plus sat through some YouTube videos, plus read "Java FX for Dummies" (which was the best book I could find for a beginner.) All of this material has taught me a lot of the basics, but some stuff that (should be) relatively simple escapes me.
For example: Let's say I have a Java FX program that uses multiple scenes on one stage. When the user clicks a "Switch!" button, the second scene is swapped out for the first. Easy. I can do all of this in one .java file, no problem. (See code below)
But my .java class file is getting really long and cumbersome to troubleshoot. It would be great if I could define/declare/initialize one scene as one class in one .java file and the second scene as another class in another .java file. This would make keeping track of the components of each scene much, much easier. The problem is, I can't figure out how to do this.
I'd imagine that you would write a Scene1.java class and then a Scene2.java class, and simply pass the stage object between the two when you want to switch scenes. But I can't find an example of how this is done, and all my attempts result in compiler errors or really scary runtime errors.
Does anyone know how this can be done? If so, what would I have to do to modify the SwitchScenes2() method below to create the new Scene2 object and pass it the stage?
Thanks! RAO
/*
JavaFXExample.java
*/
import javafx.application.*;
import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.layout.*;
import javafx.scene.control.*;
import javafx.event.*;
import javafx.geometry.*;
public class JavaFXExample extends Application{
public static void main(String[] args){
launch(args);
}
Button btnSw1;
Button btnSw2;
Button btnClose;
HBox hbox1;
VBox vbox1;
Scene scene1;
Scene scene2;
Stage stage;
#Override public void start(Stage primaryStage){
btnSw1 = new Button("Switch Scenes!");
btnSw1.setOnAction(
e -> SwitchScenes2() );
btnSw2 = new Button("Switch back!");
btnSw2.setOnAction(
e -> SwitchScenes1() );
btnClose = new Button();
btnClose.setText("Close me!");
btnClose.setOnAction(e -> CloseWindowClick());
hbox1 = new HBox(10);
hbox1.getChildren().addAll(btnSw1);
vbox1 = new VBox(10);
vbox1.getChildren().addAll(btnSw2, btnClose);
scene1 = new Scene(hbox1, 300, 300);
scene2 = new Scene(vbox1, 200, 400);
stage = primaryStage;
stage.setScene(scene1);
stage.setTitle("Example App");
stage.show();
}
public void SwitchScenes1(){
stage.setScene(scene1);
}
public void SwitchScenes2(){
stage.setScene(scene2);
}
public void CloseWindowClick(){
stage.close();
}
}

Pete as I understand you wish to separate one big java file into small files,create Java classes in each class create method(function) that will return layout(HBox,VBox, Flowpane or ....)then in your main create an object of that Java class and use those methods to build on big application.
in my sample I made one main and one separated class with one function,just to show you how its works. In my main there is 2 lables, 2 buttons one layout and one object of the separated class, by clicking the buttons scenes will change
My Main:
public class SwitchSceneSample extends Application {
public static void main(String[] args) {
launch(args);
}
Stage window;
Scene scene1, scene2;
#Override
public void start(Stage primaryStage) throws Exception {
// I am using window as primaryStage
window = primaryStage;
// Label 1
Label label1 = new Label("Welcome to the first scene!");
// Label 2
Label label2 = new Label("This is second scene!");
// Button 1, by pressing this button primaryStage will be set as scene 2
Button button1 = new Button("Go to scene 2");
button1.setOnAction(e -> window.setScene(scene2));
// Button 2, by pressing this button primaryStage will be set as scene 1
Button button2 = new Button("Click to go scene 1");
button2.setOnAction(e -> window.setScene(scene1));
// Creating an object of the class'LayoutOne.java'
LayoutOne l1 = new LayoutOne();
// set my scene 1(by calling method called 'sceneView1()' from class 'LayoutOne.java')
scene1 = new Scene(l1.sceneView1(label1, button1), 200, 200);
// Set my scene 2 inside my main class
StackPane layout2 = new StackPane();
layout2.getChildren().addAll(label2, button2);
scene2 = new Scene(layout2, 600, 300);
// Making my
window.setScene(scene1);
window.setTitle("Scene Switch Sample");
window.show();
}
}
My Second Class:
public class LayoutOne {
public VBox sceneView1(Label label, Button button) {
// Layout 1 - children are laid out in vertical column
VBox layout1 = new VBox(20);
layout1.getChildren().addAll(label, button);
return layout1;
}
}

What you will want to do is create separate classes that both have functions to return the scene. From there you will want to initialize these classes and with a button call a function that will add data to these scene or create a new blank scene (as a quick way to "delete" the scene). But if you want a more professional way to switch between scenes like this you will want to check out the TabPane().
Scene1 scene1 = new Scene1();
Scene2 scene2 = new Scene2();
TabPane tabPane = new TabPane();
Tab tab1 = new Tab();
tab1.setContent(scene1);
tabPane.getTabs().add(tab1);
Tab tab2 = new Tab();
tab2.setContent(scene2);
tabPane.getTabs().add(tab2);

Create a Manager class that contain the main method & initialize the first screen. eg.
public class VMCSManager extends Application {
private Parent content;
private static VMCSManager instance;
public VMCSManager() {
instance=this;
}
public static void main(String[] args) {
launch(args);
}
public static VMCSManager getInstance() {
return instance;
}
#Override
public void start(Stage primaryStage) throws Exception {
initializePanel();
Scene scene = new Scene(content);
stageStyle(primaryStage);
primaryStage.setScene(scene);
primaryStage.show();
}
private void initializePanel() throws IOException{
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("fxml/SimulatorDisplay.fxml"));
content = loader.load();
}
public void openCustomerPanel() throws IOException{
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("fxml/CustomerDisplay.fxml"));
content = loader.load();
Scene scene = new Scene(content);
primaryStage.setScene(scene);
primaryStage.show();
}
}
Create main controller class for the first screen. eg;
public class SimulatorController implements Initializable{
#FXML
public void clickCustomer (ActionEvent event) throws IOException{
log.info("Starting Customer Panel");
VMCSManager.getInstance().openCustomerPanel();
}
#FXML
public void clickMaintainer(ActionEvent event) throws IOException{
log.info("Starting Maintainer Panel");
VMCSManager.getInstance().openMaintainerPanel();
}
}
Lastly Create the controller class for the specified screen. eg`
public class CustomerController extends SimulatorController{
#FXML
private Label brand1Lbl;
#FXML
private Label brand2Lbl;
#FXML
private Label brand3Lbl;
#FXML
private Label brand4Lbl;
#FXML
private Label brand5Lbl;
#FXML
private Label statusLbl1;
#FXML
private Label statusLbl2;
private static final Logger log=LoggerFactory.getLogger(CustomerController.class);
public CustomerController() {
context= new BuyingStateContext();
}
public void initialize(URL location, ResourceBundle resources) {
this.location = location;
this.rb = resources;
coinsValidityFlash.setVisible(false);
insertCoinTxt.setDisable(true);
brand1Btn.setStyle("-fx-background-color: #CACACA;");
brand2Btn.setStyle("-fx-background-color: #CACACA;");
brand3Btn.setStyle("-fx-background-color: #CACACA;");
brand4Btn.setStyle("-fx-background-color: #CACACA;");
brand5Btn.setStyle("-fx-background-color: #CACACA;");
populateVending();
}
.
.
.
}
`