JavaFX でオブジェクトを移動する

// Importing necessary packages.
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class MoveObject extends Application {
  @Override public void start(Stage primaryStage) { // Our main method
    BallPane BallPane = new BallPane();

    HBox ButtonHolder = new HBox(5); // Create an Hbox named "ButtonHolder"
    Button LeftBtn = new Button("Left"); // Create a button that move the ball left
    Button RightBtn = new Button("Right"); // Create a button that move the ball Right
    Button UpBtn = new Button("Up"); // Create a button that move the ball Up
    Button DownBtn = new Button("Down"); // Create a button that move the ball Down
    ButtonHolder.getChildren().addAll(
        LeftBtn, RightBtn, UpBtn, DownBtn); // Contain all the button to the `ButtonHolder` Hbox

    // Create actions for the buttons
    LeftBtn.setOnAction(e -> BallPane.MoveLeft());
    RightBtn.setOnAction(e -> BallPane.MoveRight());
    UpBtn.setOnAction(e -> BallPane.MoveUp());
    DownBtn.setOnAction(e -> BallPane.MoveDown());

    BorderPane pane = new BorderPane(); // Create a BorderPane
    pane.setCenter(BallPane); // Set the BallPane to pane
    pane.setBottom(ButtonHolder); // Set the ButtonHolder to pane
    pane.setPadding(new Insets(0, 20, 0, 20)); // Apply necessary paddings
    BorderPane.setAlignment(ButtonHolder, Pos.CENTER); // Align the ButtonHolder

    Scene scene = new Scene(pane, 250, 250); // Create a scene
    primaryStage.setTitle("Move a Ball"); // Provide an application title "Move a Ball"
    primaryStage.setScene(scene); // Set the scene to stage
    primaryStage.show(); // Visualizing the stage.
  }

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

class BallPane extends Pane { //  Create a Pane for pane
  private double radius = 25; // Define the ball redius
  private double width = 210; // Define the ball width
  private double height = 210; // Define the ball height
  Circle Ball = new Circle(width / 2, height / 2, radius); // Calcuate the circle

  BallPane() { // Set ball properties
    Ball.setFill(Color.GREEN);
    Ball.setStroke(Color.BLACK);
    getChildren().add(Ball);
  }

  public void MoveLeft() { // Method for moving the ball left
    if (Ball.getRadius() < Ball.getCenterX()) {
      Ball.setCenterX(Ball.getCenterX() - 10);
    }
  }

  public void MoveRight() { // Method for moving the ball Right
    if (Ball.getCenterX() < width - Ball.getRadius()) {
      Ball.setCenterX(Ball.getCenterX() + 10);
    }
  }

  public void MoveUp() { // Method for moving the ball Up
    if (Ball.getRadius() < Ball.getCenterY()) {
      Ball.setCenterY(Ball.getCenterY() - 10);
    }
  }

  public void MoveDown() { // Method for moving the ball Down
    if (Ball.getCenterY() < height - Ball.getRadius()) {
      Ball.setCenterY(Ball.getCenterY() + 10);
    }
  }
}

public void MoveLeft() { // Method for moving the ball left
  if (Ball.getRadius() < Ball.getCenterX()) {
    Ball.setCenterX(Ball.getCenterX() - 10);
  }
}

public void MoveRight() { // Method for moving the ball Right
  if (Ball.getCenterX() < width - Ball.getRadius()) {
    Ball.setCenterX(Ball.getCenterX() + 10);
  }
}

public void MoveUp() { // Method for moving the ball Up
  if (Ball.getRadius() < Ball.getCenterY()) {
    Ball.setCenterY(Ball.getCenterY() - 10);
  }
}

public void MoveDown() { // Method for moving the ball Down
  if (Ball.getCenterY() < height - Ball.getRadius()) {
    Ball.setCenterY(Ball.getCenterY() + 10);
  }
}