使用箭头键移动圆圈 - Java

Question

我现在正在试验 JavaFX，教自己如何使用箭头键移动文本和项目。我制作了一个程序，如果按下箭头键，它只会在舞台上移动文本。

我想让一个圆圈围绕我的窗格而不是文本移动。我必须进行哪些更改才能使用箭头键移动我的圈子？

public void start(Stage primaryStage) {
        Pane pane = new Pane();

        int dx = 50;
        int dy = 50;
        int radius = 125;

        Circle circle = new Circle(radius,dx,dy);
        Text text = new Text(20,20,"HI");
        circle.setFill(Color.WHITE);
        circle.setStroke(Color.BLACK);

        pane.getChildren().addAll(circle, text);

        circle.setOnKeyPressed(e -> {
            switch(e.getCode()) {
            case DOWN: text.setY(text.getY() + 10);
            break;
            case UP: text.setY(text.getY() - 10);
            break;
            case LEFT: text.setX(text.getX() - 10);
            break;
            case RIGHT: text.setX(text.getX() + 10);
            break;
            default:
                if(Character.isLetterOrDigit(e.getText().charAt(0)))
                    text.setText(e.getText());
            break;      
            }
        });

        Scene scene = new Scene(pane, 250, 200);
        primaryStage.setTitle("Arrow Keys");
        primaryStage.setScene(scene);
        primaryStage.show();

        text.requestFocus();
    }

Answer 1

scene.setOnKeyPressed(e -> {
    switch (e.getCode()) {
    case DOWN:
        circle.setCenterY(circle.getCenterY() + 10);
        break;
    case UP:
        circle.setCenterY(circle.getCenterY() - 10);
        break;
    case LEFT:
        circle.setCenterX(circle.getCenterX() - 10);
        break;
    case RIGHT:
        circle.setCenterX(circle.getCenterX() + 10);
        break;
    }
});

Answer 2

就我个人而言，我会改变你在哪里听按键。我会把它放在窗格上，因为在这个例子中它始终是焦点。除此之外，如果您不希望最后一个留下，您可能必须删除并重新读取圆圈，我不在我的电脑上，所以我无法确认这一点，但生成的代码看起来像这样。

public void start(Stage primaryStage) {
        Pane pane = new Pane();

        int dx = 50;
        int dy = 50;
        int radius = 125;

        Circle circle = new Circle(radius,dx,dy);
        Text text = new Text(20,20,"HI");
        circle.setFill(Color.WHITE);
        circle.setStroke(Color.BLACK);

        pane.getChildren().addAll(circle, text);

        pane.setOnKeyPressed(e -> {
            pane.getChildren().remove(circle);
            switch(e.getCode()) {
            case DOWN: circle.setCenterY(circle.getCenterY() + 10);
            break;
            case UP: circle.setCenterY(circle.getCenterY() - 10);
            break;
            case LEFT: circle.setCenterX(circle.getCenterX() + 10);
            break;
            case RIGHT: circle.setCenterX(circle.getCenterX() - 10);
            break;    
            }
            pane.getChildren().add(circle);
        });

        Scene scene = new Scene(pane, 250, 200);
        primaryStage.setTitle("Arrow Keys");
        primaryStage.setScene(scene);
        primaryStage.show();
    }