java - 如何在程序运行时显示实时变化的文本数据？

Question

例如，我想查找车辆在远离 radio 塔的特定时刻接收的瞬时信号强度。车辆与塔的瞬时距离也会实时显示。

我可以使用 JTextArea 在程序运行时显示信号和距离的变化值吗？以下是我想做的事情的总体思路。

 public class Stuff
 {
 public static double calculateSignal(double d, double f)
        {
            GUI.d=Mover.instantDistance(animpos); //needs to be displayed


            double atten=20*(Math.log10(d))+20*(Math.log10(f))+32.44; //would also like to display this

            return atten;
        }

    ...
    JTextArea textArea_3 = new JTextArea();
    textArea_3.setEditable(false);
    textArea_3.setText(GUI.d); //would have to be converted to String
    textArea_3.setBounds(147, 481, 215, 32);
    panel_3.add(textArea_3);


    JTextArea textArea_4 = new JTextArea();
    textArea_4.setEditable(false);
    textArea_4.setText(atten); //would have to be converted to String
    textArea_4.setBounds(147, 527, 215, 27);
    panel_3.add(textArea_4);

Answer 1

您可以利用发布者监听器模式 ( code )

import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;

public class PublisherListenerSignalExample {

    private interface Listener {
        void onEventRecieved(Event e);
    }

    private static class Event {
        private double distance;
        private double atten;

        public Event(double distance, double atten) {
            this.distance = distance;
            this.atten = atten;
        }

        public double getDistance() {
            return distance;
        }

        public double getAtten() {
            return atten;
        }

    }

    private static class GUI {

        public static double d;

    }

    private static class Mover {

        public static double instantDistance(double animpos) {
            return 0;
        }

    }

    private static double distance, animpos;

    private static List<Listener> listeners = new LinkedList<>();

    private static void fire(Event event) {
        for(Listener l : listeners) {
            l.onEventRecieved(event);
        }
    }

    public static void addListener(Listener l) {
        listeners.add(l);
    }

    public static double calculateSignal(double d, double f) {

        GUI.d = Mover.instantDistance(animpos); // needs to be displayed

        double atten = 20 * (Math.log10(d)) + 20 * (Math.log10(f)) + 32.44; // would
                                                                            // also
                                                                            // like
                                                                            // to
                                                                            // display
                                                                            // this

        fire(new Event(d, atten));
        return atten;
    }

    public static void main(String[] args) {

        addListener(new Listener() {

            @Override
            public void onEventRecieved(Event e) {
                System.out.println(String.format("distance=%f atten=%f", e.getDistance(), e.getAtten()));
            }
        });

        final JTextArea textArea_3 = new JTextArea();
        textArea_3.setEditable(false);
        textArea_3.setBounds(147, 481, 215, 32);


        final JTextArea textArea_4 = new JTextArea();
        textArea_4.setEditable(false);
        textArea_4.setBounds(147, 527, 215, 27);

        addListener(new Listener() {

            @Override
            public void onEventRecieved(final Event e) {
                SwingUtilities.invokeLater(new Runnable() {

                    @Override
                    public void run() {
                        textArea_3.setText(""+e.getDistance()); //would have to be converted to String
                        textArea_4.setText(""+e.getAtten()); //would have to be converted to String
                    }
                });

            }
        });

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                JPanel panel = new JPanel();
                frame.setContentPane(panel);
                panel.add(textArea_3);
                panel.add(textArea_4);
                frame.pack();
                frame.setVisible(true);
            }
        });


        Thread worker = new Thread(new Runnable() {

            @Override
            public void run() {

                Random rnd = new Random();

                while(true) {

                    calculateSignal(rnd.nextDouble(), rnd.nextDouble());
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }

            }
        });

        worker.setDaemon(true);
        worker.start();

    }

}