JavaFX中如何让球从墙上弹开? [英] How to make the ball bounce off the walls in JavaFX?
本文介绍了JavaFX中如何让球从墙上弹开?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我是 Javafx 的新手,我正在创建一个简单的程序.我想要实现的是让球从墙上弹开,但我还没有想出如何做到这一点.另外,请随意留下关于我的代码的其他建议.
I am new to Javafx and I am creating a simple program. What I'm trying to achieve is get the ball to bounce off the walls, but I haven't figured out how to do that yet. Also, feel free to leave other suggestions about my code.
这是源代码:
public class GamePractice extends Application {
public static Circle circle;
public static Pane canvas;
private long counter = 0;
@Override
public void start(Stage primaryStage) {
canvas = new Pane();
Scene scene = new Scene(canvas, 800, 600);
primaryStage.setTitle("Game");
primaryStage.setScene(scene);
primaryStage.show();
circle = new Circle(15,Color.BLUE);
circle.relocate(100, 100);
canvas.getChildren().addAll(circle);
Timeline loop = new Timeline(new KeyFrame(Duration.millis(10), new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent t) {
if (counter++ % 10 == 0)
{
circle.setLayoutX(circle.getLayoutX() + 10);
circle.setLayoutY(circle.getLayoutY() + 10);
//This is what I currently have, am I headed the right direction?
//Check X and Y for collision with the ball
if ((circle.getTranslateX() == canvas.getWidth() - 10) || (circle.getTranslateY() == canvas.getHeight() - 10)) {
//How do I make the ball bounce?
}
}
}
}));
loop.setCycleCount(Timeline.INDEFINITE);
loop.play();
}
感谢您的帮助.
推荐答案
一个提示:你应该 避免完全相等的双值比较 a == b
.
One hint: you should avoid comparing double values for exact equality a == b
.
对您的代码进行一些小的更改,您就已经在那里了:
With some small changes of your code you're already there:
package learn.javafx;
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 GamePractice extends Application {
public static Circle circle;
public static Pane canvas;
@Override
public void start(final Stage primaryStage) {
canvas = new Pane();
final Scene scene = new Scene(canvas, 800, 600);
primaryStage.setTitle("Game");
primaryStage.setScene(scene);
primaryStage.show();
circle = new Circle(15, Color.BLUE);
circle.relocate(100, 100);
canvas.getChildren().addAll(circle);
final Timeline loop = new Timeline(new KeyFrame(Duration.millis(10), new EventHandler<ActionEvent>() {
double deltaX = 3;
double deltaY = 3;
@Override
public void handle(final ActionEvent t) {
circle.setLayoutX(circle.getLayoutX() + deltaX);
circle.setLayoutY(circle.getLayoutY() + deltaY);
final Bounds bounds = canvas.getBoundsInLocal();
final boolean atRightBorder = circle.getLayoutX() >= (bounds.getMaxX() - circle.getRadius());
final boolean atLeftBorder = circle.getLayoutX() <= (bounds.getMinX() + circle.getRadius());
final boolean atBottomBorder = circle.getLayoutY() >= (bounds.getMaxY() - circle.getRadius());
final boolean atTopBorder = circle.getLayoutY() <= (bounds.getMinY() + circle.getRadius());
if (atRightBorder || atLeftBorder) {
deltaX *= -1;
}
if (atBottomBorder || atTopBorder) {
deltaY *= -1;
}
}
}));
loop.setCycleCount(Timeline.INDEFINITE);
loop.play();
}
public static void main(final String[] args) {
launch(args);
}
}
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