animation - 如何更改 JavaFX 中动画计时器的速度？

Question

我正在尝试更改 AnimationTimer 的速度，以便代码运行得更慢，这是我到目前为止的代码:

AnimationTimer timer = new AnimationTimer() {

    @Override
    public void handle(long now) {    
        if (upOrDown != 1) {
            for (int i = 0; i < 4; i++) {
                snakePositionDown[i] = snake[i].getX();
                snakePositionDownY[i] = snake[i].getY();
            }

            snake[0].setY(snake[0].getY() + 25);

            for (int i = 1; i < 4; i++) {
                snake[i].setX(snakePositionDown[i - 1]);
                snake[i].setY(snakePositionDownY[i - 1]);
            }

            leftOrRight = 2;
            upOrDown = 0;
        }
    }

};

timer.start();

如何让 AnimationTimer 运行得更慢？

提前致谢!

Answer 1

您可以使用时间轴来实现此目的。调整 Timeline.rate 属性还允许您更新“速度”:

// update once every second (as long as rate remains 1)
Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(1), event -> {

    if (upOrDown != 1) {
        for (int i = 0; i < 4; i++) {
            snakePositionDown[i] = snake[i].getX();
            snakePositionDownY[i] = snake[i].getY();
        }
        snake[0].setY(snake[0].getY() + 25);
        for (int i = 1; i < 4; i++) {
            snake[i].setX(snakePositionDown[i - 1]);
            snake[i].setY(snakePositionDownY[i - 1]);
        }
        leftOrRight = 2;
        upOrDown = 0;
    }    

}));
timeline.setCycleCount(Animation.INDEFINITE);
timeline.play();

...

// double speed
timeline.setRate(2);