How to change Scenes in JavaFX

To change scenes in JavaFX, you can use the Scene and Stage classes from the javafx.scene package. The Scene class represents a scene in a JavaFX application, and the Stage class represents the stage on which the scene is displayed.

Here’s an example of how to switch scenes in JavaFX:

// Create the new scene
Scene newScene = new Scene(newParent, width, height);

// Get the current stage
Stage currentStage = (Stage)currentNode.getScene().getWindow();

// Set the new scene on the stage
currentStage.setScene(newScene);

In this code, newParent is the root Node that will be displayed in the new scene, width and height are the dimensions of the new scene, and currentNode is a reference to a Node in the current scene.

You can use this code to switch to a new scene whenever you need to, such as when a button is clicked or some other user interaction occurs.

Add Loader before changing scene JavaFx

To add a loader before changing scenes in JavaFX, you can use the ProgressIndicator class from the javafx.scene.control package.

This class provides a visual indicator that shows that some background process is running, such as loading data from a server or performing a long-running computation.

Here’s an example of how to add a loader before changing scenes in JavaFX:

// Create a new progress indicator
ProgressIndicator loader = new ProgressIndicator();

// Set the size of the progress indicator
loader.setPrefSize(100, 100);

// Set the position of the progress indicator
loader.setLayoutX(scene.getWidth() / 2 - 50);
loader.setLayoutY(scene.getHeight() / 2 - 50);

// Add the progress indicator to the current scene
scene.getRoot().getChildren().add(loader);

// Perform the long-running task in a background thread
new Thread(() -> {
  // Load the data
  loadData();

  // Create the new scene
  Scene newScene = new Scene(newParent, width, height);

  // Set the new scene on the stage
  Platform.runLater(() -> {
    Stage currentStage = (Stage)currentNode.getScene().getWindow();
    currentStage.setScene(newScene);
  });
}).start();

In this code, scene is the current Scene, newParent is the root Node that will be displayed in the new scene, width and height are the dimensions of the new scene, and currentNode is a reference to a Node in the current scene.

The loadData() method is a placeholder for the long-running task that you want to perform before switching to the new scene.

This code creates a new ProgressIndicator and adds it to the current scene. It then starts a new thread to perform the long-running task, and when the task is complete, it switches to the new scene on the JavaFX application’s main thread.

This ensures that the UI remains responsive while the long-running task is being performed.

Assign Inline CSS to Scene

To assign inline CSS styles to a scene in JavaFX, you can use the setStyle() method of the Scene class. This method takes a string containing the CSS styles that you want to apply to the scene, and applies them to the scene’s root Node.

Here’s an example of how to use the setStyle() method to apply inline CSS styles to a scene:

// Create the new scene
Scene newScene = new Scene(newParent, width, height);

// Set the inline CSS styles for the scene
newScene.setStyle("-fx-background-color: #fff; -fx-font-size: 12pt;");

// Get the current stage
Stage currentStage = (Stage)currentNode.getScene().getWindow();

// Set the new scene on the stage
currentStage.setScene(newScene);

In this code, newParent is the root Node that will be displayed in the new scene, width and height are the dimensions of the new scene, and currentNode is a reference to a Node in the current scene.

You can use any valid CSS styles in the string passed to the setStyle() method, and they will be applied to the scene’s root Node. This allows you to easily customize the look and feel of your JavaFX scenes.

Finally, destroy a Scene

To destroy a scene in JavaFX, you can use the remove() method of the Parent class, which is the superclass of the Scene class. This method removes the scene from the node tree, which effectively destroys it.

Here’s an example of how to destroy a scene in JavaFX:

// Get the current scene
Scene currentScene = (Scene)currentNode.getScene();

// Get the parent of the current scene
Parent currentParent = currentScene.getRoot();

// Remove the current scene from the parent
currentParent.getChildren().remove(currentScene);

In this code, currentNode is a reference to a Node in the current scene, currentScene is the Scene object that you want to destroy, and currentParent is the parent Node of the current scene.

Once the scene is removed from the node tree, it will no longer be displayed on the stage, and any resources it was using (such as images, fonts, etc.) will be eligible for garbage collection.

Note that this code only destroys the scene itself, but does not close the JavaFX application. To close the application, you can use the Platform.exit() method, which will shut down the JavaFX runtime and terminate the application. Here’s an example:

// Destroy the current scene
currentParent.getChildren().remove(currentScene);

// Close the JavaFX application
Platform.exit();

This code destroys the current scene and then closes the JavaFX application.