JavaFX Canvas没有拾取关键事件

Question

我有以下代码显示带有3个连续hello世界的JavaFX Canvas

    StackPane root = new StackPane();

        Canvas canvas = new Canvas(250,250);
        canvas.setOnMouseEntered((a) -> System.out.println("hi"));
        canvas.setOnMousePressed((a) -> System.out.println("focus"));
        canvas.setOnKeyReleased(new EventHandler<KeyEvent>() {

            @Override
            public void handle(KeyEvent event) {
                System.out.println("Handled");
            }
        });
//        canvas.setOnKeyPressed((a) -> System.out.println("hi"));

        GraphicsContext context = canvas.getGraphicsContext2D();
        context.setFill(Color.BLUE);
        final int fontSize = 15, fontSpace = 5;
        context.setFont(Font.font(15));

        context.fillText("hello world", 75, 75);
        context.fillText("hello world", 75, 75 + fontSize + fontSpace);
        context.fillText("hello world", 75, 75 + (fontSize + fontSpace) * 2);

        root.getChildren().add(canvas);

        Scene scene = new Scene(root, 300, 250);

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();

当我将鼠标悬停在它上面时，它会打印“hi”。当我点击它时，它会打印“焦点”。当我按键时，没有任何反应。有什么我想念的吗？

Answer 1

你需要

canvas.setFocusTraversable(true);

因为画布默认情况下没有设置focusTraversable。

Answer 2

添加以下行：

canvas.addEventFilter(MouseEvent.ANY, (e) -> canvas.requestFocus());

单击画布后，画布将请求焦点和识别键事件。