弹弹球

Posted 2022-12-06 夏芷雨涵梦

题目：显示一个弹球的小程序，可以让用户添加和移除球。可以通过鼠标的按下和释放来进行暂停和运行，通过加减两个按钮来进行球的个数的增减，通过顶端的滚动条来控制球移动的速度。

时间：2019.3.31

代码：

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.DoubleProperty;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ScrollBar;
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.util.Duration;

import java.awt.*;
import java.util.Random;

public class BounceBall extends Application 
    public void start(Stage primaryStage) 
        BallPane ballPane = new BallPane();
        ballPane.setStyle("-fx-border-color: yellow");
        Button btAdd = new Button("+");
        Button btSubtract = new Button("-");
        HBox hBox = new HBox(10);
        hBox.getChildren().addAll(btAdd, btSubtract);
        hBox.setAlignment(Pos.CENTER);

        btAdd.setOnAction(e -> ballPane.add());
        btSubtract.setOnAction(e -> ballPane.subtract());

        btAdd.setOnMousePressed(e -> ballPane.pause());
        btAdd.setOnMouseReleased(e -> ballPane.play());
        ScrollBar sbSpeed = new ScrollBar();
        sbSpeed.setMax(20);
        sbSpeed.setValue(10);
        ballPane.rateProperty().bind(sbSpeed.valueProperty());

        BorderPane pane = new BorderPane();
        pane.setCenter(ballPane);
        pane.setTop(sbSpeed);
        pane.setBottom(hBox);

        Scene scene = new Scene(pane, 250, 150);
        primaryStage.setTitle("弹弹球");
        primaryStage.setScene(scene);
        primaryStage.show();
    


    private class BallPane extends Pane 
        private Timeline animation;

        public BallPane() 
            animation = new Timeline(
                    new KeyFrame(Duration.millis(50), e -> moveBall())
            );
            animation.setCycleCount(Timeline.INDEFINITE);
            animation.play();
        

        public void add() 
            Color color = new Color(Math.random(), Math.random(), Math.random(), 0.5);
            getChildren().add(new Ball(30, 30, 20, color));
        

        public void subtract() 
            if (getChildren().size() > 0)
                getChildren().remove(getChildren().size() - 1);
        

        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() 
            for (Node node : this.getChildren()) 
                Ball ball = (Ball) node;
                if (ball.getCenterX() < ball.getRadius() || ball.getCenterX() > getWidth() - ball.getRadius()) 
                    ball.dx *= -1;
                
                if (ball.getCenterY() < ball.getRadius() || ball.getCenterY() > getHeight() - ball.getRadius()) 
                    ball.dy *= -1;
                
                ball.setCenterX(ball.dx + ball.getCenterX());
                ball.setCenterY(ball.dy + ball.getCenterY());

            
        
    

    class Ball extends Circle 
        private double dx = 1, dy = 1;

        Ball(double x, double y, double radius, Color color) 
            super(x, y, radius);
            setFill(color);
        
    

运行结果：