使用多线程在特定时间内更改javafx圈子的颜色

问题描述

我正在用javafx创建交通信号灯模拟器，它使用多线程概念每2秒更改一次颜色(第一个红灯闪烁并保持2秒).我有我的代码如下.但是它没有按预期工作.它只会闪烁所有指示灯，直到有人可以帮我弄清楚我出了什么问题吗?谢谢

I am creating traffic light simulator with javafx that changes colour in every 2 seconds (first red light blinks and remain for 2 seconds) using the concept of multithreading. I have my code as given below. But it doesn't work as expected. It just blinks all light and sto Can somebody help me figure it out where I went wrong? Thanks

public void startThreads() throws InterruptedException {

    Runnable taskOne = new Runnable(){
        @Override
        public void run(){
            try {
                Platform.runLater(new Runnable() {
                    @Override
                    public void run() {
                        circle.setFill(Color.RED);
                        circle1.setFill(Color.GREY);
                        circle2.setFill(Color.GREY);
                    }
                  });
                Thread.currentThread().sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    };

    Runnable taskTwo ......

    Runnable taskThree .....

    Thread thread1 = new Thread(taskOne);
    Thread thread2 = new Thread(taskTwo);
    Thread thread3 = new Thread(taskThree);

    //Start thread 1
    thread1.start();
    thread1.join();

    //start thread 2
    thread2.start();
    thread2.join();

    //Start thread 3
    thread3.start();
    thread3.join();
}

推荐答案

来自 Thread.join

这是

thread1.start();
thread1.join();

与

相比，没有提供任何好处

doesn't provide any benefits compared to

taskOne.run();

因为这会停止执行调用join的方法，直到Thread完成.

since this stops the execution of the method invoking join until the Thread completes.

通过使用Timeline，可以以一种更加优雅的方式实现您要执行的操作:

It's possible to achieve what you're trying to do in a much more elegant way by using Timeline:

Timeline timeline = new Timeline(
    new KeyFrame(Duration.ZERO, evt -> {
        circle.setFill(Color.RED);
        circle1.setFill(Color.GREY);
        circle2.setFill(Color.GREY);
    }),
    new KeyFrame(Duration.seconds(2), evt -> {
        // TODO: GUI modifications for second state
    }),
    new KeyFrame(Duration.seconds(4), evt -> {
        // TODO: GUI modifications for third state
    })
);
timeline.play();

您可能需要调整第三个KeyFrame的持续时间. Duration参数指定从动画开始开始的时间. EventHandler<ActionEvent>在JavaFX应用程序线程上执行，并且不能包含长时间运行的代码，例如Thread.sleep.您可能需要添加其他KeyFrame.

You may need to adjust the duration for the third KeyFrame. The Duration parameter specifies the time from the beginning of the animation. The EventHandler<ActionEvent>s are executed on the JavaFX application thread and must not contain long-running code such as Thread.sleep. You may need to add additional KeyFrames.

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