import javafx.animation.KeyFrame;

import javafx.animation.Timeline;

import javafx.beans.property.DoubleProperty;

import javafx.scene.layout.Pane;

import javafx.scene.paint.Color;

import javafx.scene.shape.Circle;

import javafx.util.Duration;

public class BallPane extends Pane{

    private double radius = 20;

    private double x = radius, y = radius;

    private double dx = 1, dy = 1;

    private Circle circle = new Circle(x, y, radius);

    private Timeline animation;

    public BallPane() {

        circle.setStroke(Color.BLACK);

        circle.setFill(Color.ORANGE);

        getChildren().add(circle);

        animation = new Timeline(

                new KeyFrame(Duration.millis(50), e -> moveBall()));

        animation.setCycleCount(Timeline.INDEFINITE);

        animation.play();

    }

    public void play() {

        animation.play();

    }

    public void pause() {

        animation.pause();

    }

    public void increaseSpeed() {

        animation.setRate(animation.getRate() + 0.1);

    }

    public void decreaseSpeed() {

        animation.setRate(animation.getRate() > 0 ? animation.getRate() - 0.1 : 0);

    }

    public DoubleProperty rateProperty() {

        return animation.rateProperty();

    }

    protected void moveBall() {

        if(x < radius || x > getWidth() - radius) {

            dx *= -1;

        }

        if(y < radius || y > getHeight() - radius) {

            dy *= -1;

        }

        x += dx;

        y += dy;

        circle.setCenterX(x);

        circle.setCenterY(y);

    }

}

import javafx.application.Application;

import javafx.scene.Scene;

import javafx.scene.input.KeyCode;

import javafx.stage.Stage;

public class BounceBallControl extends Application{

    @Override

    public void start(Stage primaryStage) throws Exception {

        BallPane ballPane = new BallPane();

        ballPane.setOnMousePressed(e -> ballPane.pause());

        ballPane.setOnMouseReleased(e -> ballPane.play());

        //控制速度

        ballPane.setOnKeyPressed(e -> {

            if(e.getCode() == KeyCode.UP) {

                ballPane.increaseSpeed();

            }

            else if(e.getCode() == KeyCode.DOWN) {

                ballPane.decreaseSpeed();

            }

        });

        Scene scene = new Scene(ballPane, 250, 150);

        primaryStage.setTitle("Bounce Ball Control");

        primaryStage.setScene(scene);

        primaryStage.show();

        //将输入焦点设置到ballPane上

        ballPane.requestFocus();

    }

    public static void main(String[] args) {

        Application.launch(args);

    }

}