我如何使用多线程切换每盏灯中的Java中的交通信号灯只能分别吹3秒钟

Question

我制造了一个交通灯刺激系统，在该系统中，每个交通信号灯（绿色，红色，黄色）分别吹出3秒钟。我成功地创建了该系统的GUI。

public class TrafficLightSimulator extends Application implements Runnable{
    Circle red = new Circle();
    Circle green = new Circle();
    Circle yellow = new Circle();
    Button b1 = new Button();
@Override
public void start(Stage stage) {
    //Drawing a Rectangle 
    Rectangle rectangle = new Rectangle();

    //grid layout
    GridPane grid = new GridPane();
    grid.setHgap(20);
    grid.setVgap(5);
//buttons
    HBox hbButtons = new HBox();
    Button buttonStart = new Button("Start");
    Button buttonStop = new Button("Stop");
  buttonStart.setOnAction(new EventHandler<ActionEvent>() {
        public void handle(ActionEvent event) {
        green.setFill(Color.YELLOW);
}
    });
   buttonStop.setOnAction(new EventHandler<ActionEvent>() {
        public void handle(ActionEvent event) {
   TrafficLightSimulator tl=new TrafficLightSimulator();
   Thread t1=new Thread(tl);
   t1.start();
        }
    });
    //labels and textfeilds
    Label lblGreen = new Label("Green");
    TextField tfGreen = new TextField("3");
    Label lblYellow = new Label("Yellow");
    TextField tfYellow = new TextField("3");
    Label lblRed = new Label("Red");
    TextField tfRed = new TextField("3");
    grid.add(lblGreen, 0, 0);
    grid.add(tfGreen, 1, 0);
    grid.add(lblYellow, 0, 1);
    grid.add(tfYellow, 1, 1);
    grid.add(lblRed, 0, 2);
    grid.add(tfRed, 1, 2);
    grid.setPadding(new Insets(320, 5, 30, 40));

    hbButtons.getChildren().addAll(buttonStart, buttonStop);
    hbButtons.setAlignment(Pos.BOTTOM_CENTER);
    //Setting the properties of the rectangle 
    rectangle.setX(150);
    rectangle.setY(75);
    rectangle.setWidth(400);
    rectangle.setHeight(200);
    rectangle.setArcHeight(50);
    rectangle.setArcWidth(50);
    Color c = Color.web("#404040");
    Color color1 = Color.web("#404040");
    Color color2 = Color.web("#808080");
    Color greenColor = Color.web("#00FF00");
    rectangle.setFill(c);
    //setting circle properties
    green.setCenterX(230);
    green.setCenterY(170);
    green.setRadius(50);
    green.setFill(greenColor);
    yellow.setCenterX(345);
    yellow.setCenterY(170);
    yellow.setRadius(50);
    yellow.setFill(color2);
    red.setCenterX(465);
    red.setCenterY(170);
    red.setRadius(50);
    red.setFill(color2);
    hbButtons.setPadding(new Insets(15, 12, 15, 12));
    hbButtons.setSpacing(10);   // Gap between nodes
    //Creating a Group object  
    StackPane rootPane = new StackPane();
    Pane p1 = new Pane(red, green, yellow);
    Pane p2 = new Pane(rectangle);
    grid.add(hbButtons, 2, 2, 2, 1);
    //  grid.add(grid, 2, 0, 0, 0);
    rootPane.getChildren().addAll(p2, p1, grid);
    //Creating a scene object 
    Scene scene = new Scene(rootPane, 600, 500);
    //Setting title to the Stage 
    stage.setTitle("Drawing a Rectangle");
    //Adding scene to the stage 
    stage.setScene(scene);
    //Displaying the contents of the stage 
    stage.show();
}

我是多线程的新手，但是我无法实现灯光可以改变特定时序

的颜色的代码

我已经编码了其中的一部分

public static void main(String args[]) {
    launch(args);
}
@Override
public void run() {
    while (true) {
        try {
            Thread.sleep(400);
        } catch (InterruptedException e) {
            System.out.println(e);
        }
        green.setFill(Color.RED);
        //  green.setFill(Color.GREEN);
        System.out.println("hello");
    }
}

Answer 1

将开始按钮的事件处理程序更改为：

buttonStart.setOnAction(new EventHandler<ActionEvent>() {
    public void handle(ActionEvent event) {
        Thread t = new Thread() {
            @Override
            public void run() {
                try {
                    green.setFill(Color.GREEN);
                    Thread.sleep(3000L);
                    green.setFill(Color.GRAY);
                    yellow.setFill(Color.YELLOW);
                    Thread.sleep(3000L);
                    yellow.setFill(Color.GRAY);
                    red.setFill(Color.RED);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        };
        t.start();
    }
});

请注意，圆的颜色在新线程中更新。

在Javafx中，事件和UI更新均由同一Javafx应用程序线程处理。如果我们不在其他线程中运行这些UI更新，则渲染将阻塞直到活动处理程序完成。

Answer 2

谢谢！！！它的工作正常，但我认为我们必须在代码中更改一些位，才能从文本框中获取文本值的计时器。而且我们还需要添加一个按钮停止操作侦听器才能停止线程

buttonStart.setOnAction(new EventHandler<ActionEvent>() {
            public void handle(ActionEvent event) {
                Thread t = new Thread() {
                    @Override
                    public void run() {
                        try {
                            green.setFill(Color.GREEN);
                            System.out.println(Long.parseLong(tfGreen.getText()));
                            Thread.sleep(Long.parseLong(tfGreen.getText()) * 1000);
                            green.setFill(Color.GRAY);
                            yellow.setFill(Color.YELLOW);
                            Thread.sleep(Long.parseLong(tfYellow.getText()) * 1000);
                            yellow.setFill(Color.GRAY);
                            red.setFill(Color.RED);
                            Thread.sleep(Long.parseLong(tfRed.getText()) * 1000);
                            red.setFill(Color.GRAY);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                };
                t.start();
                buttonStop.setOnAction(new EventHandler<ActionEvent>() {
                    public void handle(ActionEvent event) {
                        green.setFill(Color.GRAY);
                        yellow.setFill(Color.GRAY);
                        red.setFill(Color.GRAY);
                        t.stop();
                    }
                });
            }
        });