JavaFX动画球示例

妖狐艹你老母 2023-02-15 05:11 17阅读 0赞

弹跳球是JavaFx中动画的“ Hello World”。 它很容易编写，易于理解，甚至从这个原始阶段就可以揭示JavaFx的潜力。

我们将首先创建一个运动球，该运动球将为随后的弹跳球奠定基础。

## 1.移动球示例 ##

除了基本设置之外，此代码只有一条重要的代码行。 我们创建`Timeline` 。 该`Timeline`具有两个重要属性： `KeyFrame`和`KeyValue` 。 我们用简单的英语对`Timeline`说的是“在3秒内将球从原处移到`Pane`的尽头”。 然后，我们还请它（请）重复两次并贴上！

MovingBall.java

package com.mkyong.javafx.animatedball;
    
    import javafx.animation.KeyFrame;
    import javafx.animation.KeyValue;
    import javafx.animation.Timeline;
    import javafx.application.Application;
    import javafx.geometry.Bounds;
    import javafx.scene.Scene;
    import javafx.scene.layout.Pane;
    import javafx.scene.paint.Color;
    import javafx.scene.shape.Circle;
    import javafx.stage.Stage;
    import javafx.util.Duration;
    
    public class MovingBall extends Application{
    	
        @Override
        public void start(Stage stage) {
        	Pane canvas = new Pane();
        	Scene scene = new Scene(canvas, 300, 300);
        	Circle ball = new Circle(10, Color.RED);
            ball.relocate(0, 10);
            
            canvas.getChildren().add(ball);
            
            stage.setTitle("Moving Ball");
            stage.setScene(scene);
            stage.show();
            
            Bounds bounds = canvas.getBoundsInLocal();
            Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(3), 
                    new KeyValue(ball.layoutXProperty(), bounds.getMaxX()-ball.getRadius())));
            timeline.setCycleCount(2);
            timeline.play();
        }
        
        public static void main(String[] args) {
            launch();
        }
    }

输出：

![javafx-animated-ball-example-1][]![javafx-animated-ball-example-1][javafx-animated-ball-example-1 1]

## 2.弹跳球 ##

快速查看代码后，您会发现与上一个代码的相似之处。 除了`Timeline`现在具有`EventHandler`之外，我们的设置几乎相同。 除非球位于`Pane`的边界处，否则handle方法中的代码将球移动`dx`和`dy` ，取决于球所在的位置，将`dx`和`dy`更改为负步（换句话说，使球以其他方式移动） 。

BouncingBall.java

package com.mkyong.javafx.animatedball;
    
    import javafx.animation.KeyFrame;
    import javafx.animation.Timeline;
    import javafx.application.Application;
    import javafx.event.ActionEvent;
    import javafx.event.EventHandler;
    import javafx.geometry.Bounds;
    import javafx.scene.Scene;
    import javafx.scene.layout.Pane;
    import javafx.scene.paint.Color;
    import javafx.scene.shape.Circle;
    import javafx.stage.Stage;
    import javafx.util.Duration;
    
    public class BouncingBall extends Application{
    	
        @Override
        public void start(Stage stage) {
        	
        	Pane canvas = new Pane();
        	Scene scene = new Scene(canvas, 300, 300, Color.ALICEBLUE);
        	Circle ball = new Circle(10, Color.CADETBLUE);
            ball.relocate(5, 5);
            
            canvas.getChildren().add(ball);
            
            stage.setTitle("Animated Ball");
            stage.setScene(scene);
            stage.show();
            
            Timeline timeline = new Timeline(new KeyFrame(Duration.millis(20), 
                    new EventHandler<ActionEvent>() {
    
            	double dx = 7; //Step on x or velocity
            	double dy = 3; //Step on y
            	
                @Override
                public void handle(ActionEvent t) {
                	//move the ball
                	ball.setLayoutX(ball.getLayoutX() + dx);
                	ball.setLayoutY(ball.getLayoutY() + dy);
    
                    Bounds bounds = canvas.getBoundsInLocal();
                    
                    //If the ball reaches the left or right border make the step negative
                    if(ball.getLayoutX() <= (bounds.getMinX() + ball.getRadius()) || 
                            ball.getLayoutX() >= (bounds.getMaxX() - ball.getRadius()) ){
    
                    	dx = -dx;
    
                    }
    
                    //If the ball reaches the bottom or top border make the step negative
                    if((ball.getLayoutY() >= (bounds.getMaxY() - ball.getRadius())) || 
                            (ball.getLayoutY() <= (bounds.getMinY() + ball.getRadius()))){
    
                    	dy = -dy;
    
                    }
                }
            }));
            timeline.setCycleCount(Timeline.INDEFINITE);
            timeline.play();
        }
        
        public static void main(String[] args) {
            launch();
        }
    }

输出：

![javafx-animated-ball-example-2][]![javafx-animated-ball-example-2][javafx-animated-ball-example-2 1]

## 3.您的第一个游戏 ##

在尝试“弹跳球”示例时，我想了一下，如果我将其全部透明并添加一个`MouseEvent`来关闭应用程序，该怎么办？ 好吧……你猜怎么着……我最终试图在桌面上接住一个弹跳球！ 这就是我用JavaFx制作第一款游戏的方式！ 请享用！

MyFirstGame.java

package com.mkyong.javafx.animatedball;
    
    import javafx.animation.KeyFrame;
    import javafx.animation.Timeline;
    import javafx.application.Application;
    import javafx.application.Platform;
    import javafx.event.ActionEvent;
    import javafx.event.EventHandler;
    import javafx.geometry.Bounds;
    import javafx.scene.Scene;
    import javafx.scene.input.MouseEvent;
    import javafx.scene.layout.Pane;
    import javafx.scene.paint.Color;
    import javafx.scene.shape.Circle;
    import javafx.stage.Stage;
    import javafx.stage.StageStyle;
    import javafx.util.Duration;
    
    public class MyFirstGame extends Application{
    	
        @Override
        public void start(Stage stage) {
        	
        	Pane canvas = new Pane();
        	Scene scene = new Scene(canvas, 300, 300, Color.TRANSPARENT);
        	Circle ball = new Circle(10, Color.DARKSLATEBLUE);
            ball.relocate(5, 5);
            
            canvas.getChildren().add(ball);
                    
            stage.initStyle(StageStyle.TRANSPARENT);
            scene.addEventFilter(MouseEvent.MOUSE_PRESSED, new EventHandler<MouseEvent>() {
                @Override
                public void handle(MouseEvent mouseEvent) {
                	Platform.exit();
                    System.exit(0);
                }
            });
            stage.setTitle("Animated Ball");
            stage.setScene(scene);
            stage.show();
            
            Timeline timeline = new Timeline(new KeyFrame(Duration.millis(20), new EventHandler<ActionEvent>() {
            	double dx = 7; //Step on x or velocity
            	double dy = 3; //Step on y
            	
                @Override
                public void handle(ActionEvent t) {
                	//move the ball
                	ball.setLayoutX(ball.getLayoutX() + dx);
                	ball.setLayoutY(ball.getLayoutY() + dy);
    
                    Bounds bounds = canvas.getBoundsInLocal();
                    
                    //If the ball reaches the left or right border make the step negative
                    if(ball.getLayoutX() <= (bounds.getMinX() + ball.getRadius()) || 
                            ball.getLayoutX() >= (bounds.getMaxX() - ball.getRadius()) ){
    
                    	dx = -dx;
    
                    }
    
                    //If the ball reaches the bottom or top border make the step negative
                    if((ball.getLayoutY() >= (bounds.getMaxY() - ball.getRadius())) || 
                            (ball.getLayoutY() <= (bounds.getMinY() + ball.getRadius()))){
    
                    	dy = -dy;
    
                    }
                    
                }
            }));
            timeline.setCycleCount(Timeline.INDEFINITE);
            timeline.play();
        }
        
        public static void main(String[] args) {
            launch();
        }
    }

输出：

![javafx-animated-ball-example-3][]![javafx-animated-ball-example-3][javafx-animated-ball-example-3 1]

## 参考文献 ##

1.  [实际运行中的Java 8 – Raoul-Gabriel Urma，Mario Fusco和Alan Mycroft][Java 8 _ Raoul-Gabriel Urma_Mario Fusco_Alan Mycroft]
2.  [动画基础知识– Oracle][Oracle]

标签： [球][Link 1] [几何][Link 2] [javafx][] [时间轴][Link 3]

> 翻译自: [https://mkyong.com/javafx/javafx-animated-ball-example/][https_mkyong.com_javafx_javafx-animated-ball-example]

[javafx-animated-ball-example-1]: http://imgconvert.csdnimg.cn/aHR0cDovL3d3dy5ta3lvbmcuY29tL3dwLWNvbnRlbnQvdXBsb2Fkcy8yMDE3LzAxL2phdmFmeC1hbmltYXRlZC1iYWxsLWV4YW1wbGUtMS5naWY
[javafx-animated-ball-example-1 1]: http://imgconvert.csdnimg.cn/aHR0cHM6Ly93d3cubWt5b25nLmNvbS93cC1jb250ZW50L3VwbG9hZHMvMjAxNy8wMS9qYXZhZngtYW5pbWF0ZWQtYmFsbC1leGFtcGxlLTEuZ2lm
[javafx-animated-ball-example-2]: http://imgconvert.csdnimg.cn/aHR0cDovL3d3dy5ta3lvbmcuY29tL3dwLWNvbnRlbnQvdXBsb2Fkcy8yMDE3LzAxL2phdmFmeC1hbmltYXRlZC1iYWxsLWV4YW1wbGUtMi5naWY
[javafx-animated-ball-example-2 1]: http://imgconvert.csdnimg.cn/aHR0cHM6Ly93d3cubWt5b25nLmNvbS93cC1jb250ZW50L3VwbG9hZHMvMjAxNy8wMS9qYXZhZngtYW5pbWF0ZWQtYmFsbC1leGFtcGxlLTIuZ2lm
[javafx-animated-ball-example-3]: http://imgconvert.csdnimg.cn/aHR0cDovL3d3dy5ta3lvbmcuY29tL3dwLWNvbnRlbnQvdXBsb2Fkcy8yMDE3LzAxL2phdmFmeC1hbmltYXRlZC1iYWxsLWV4YW1wbGUtMy5naWY
[javafx-animated-ball-example-3 1]: http://imgconvert.csdnimg.cn/aHR0cHM6Ly93d3cubWt5b25nLmNvbS93cC1jb250ZW50L3VwbG9hZHMvMjAxNy8wMS9qYXZhZngtYW5pbWF0ZWQtYmFsbC1leGFtcGxlLTMuZ2lm
[Java 8 _ Raoul-Gabriel Urma_Mario Fusco_Alan Mycroft]: https://www.manning.com/books/java-8-in-action
[Oracle]: http://docs.oracle.com/javafx/2/animations/basics.htm
[Link 1]: https://mkyong.com/tag/ball/
[Link 2]: https://mkyong.com/tag/geometry/
[javafx]: https://mkyong.com/tag/javafx/
[Link 3]: https://mkyong.com/tag/timeline/
[https_mkyong.com_javafx_javafx-animated-ball-example]: https://mkyong.com/javafx/javafx-animated-ball-example/