java - 如何从私有(private)内部类转换为可运行接口(interface)？

Question

所以我给出了如下的工作代码，但是我必须将其转换为使用可运行的接口(interface)

package lab12;

 import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class MultiThreaded2 extends JFrame implements ActionListener {
public static final int WIDTH = 600;
public static final int HEIGHT = 400;
public static final int FILL_WIDTH = 600;
public static final int FILL_HEIGHT = 400;
public static final int SQUARE_SIZE = 10;
public static final int PAUSE = 100; // milliseconds

private JPanel box;

public static void main(String[] args) {
    MultiThreaded2 gui = new MultiThreaded2();
    gui.setVisible(true);
}

public MultiThreaded2() {
    setSize(WIDTH, HEIGHT);
    setTitle("Threaded Fill Demo");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    setLayout(new BorderLayout());

    box = new JPanel();
    add(box, BorderLayout.CENTER);

    JPanel buttonPanel = new JPanel();
    buttonPanel.setLayout(new FlowLayout());

    JButton startButton = new JButton("Start");
    startButton.addActionListener(this);
    buttonPanel.add(startButton);

    JButton stopButton = new JButton("Stop");
    stopButton.addActionListener(this);
    buttonPanel.add(stopButton);
    add(buttonPanel, BorderLayout.SOUTH);
}

public void run() {
    Graphics g = box.getGraphics();

    int count = 0;

    for (int y = 0; y < FILL_HEIGHT; y = y + SQUARE_SIZE) {
        for (int x = 0; x < FILL_WIDTH; x = x + SQUARE_SIZE) {

            if (count % 2 == 0) {
                g.setColor(Color.red);
                g.fillRect(x, y, SQUARE_SIZE, SQUARE_SIZE);
            } else {
                g.setColor(Color.blue);
                g.drawRect(x, y, SQUARE_SIZE, SQUARE_SIZE);
            }
            try {
                Thread.sleep(PAUSE);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            count++;
        }
    }
}


public void actionPerformed(ActionEvent e) {
    if (e.getActionCommand().equals("Start")) {
        SecondThread secondThread = new SecondThread();
        secondThread.start();
    } else if (e.getActionCommand().equals("Stop")) {
        System.exit(0);
    }
}

private class SecondThread extends Thread {
    public void run() {
        Graphics g = box.getGraphics();

        int count = 0;

        for (int y = 0; y < FILL_HEIGHT; y = y + SQUARE_SIZE) {
            for (int x = 0; x < FILL_WIDTH; x = x + SQUARE_SIZE) {

                if (count % 2 == 0) {
                    g.setColor(Color.red);
                    g.fillRect(x, y, SQUARE_SIZE, SQUARE_SIZE);
                } else {
                    g.setColor(Color.blue);
                    g.drawRect(x, y, SQUARE_SIZE, SQUARE_SIZE);
                }
                try {
                    Thread.sleep(PAUSE);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                count++;
            }
        }
    }

}

}

我知道我必须对公共(public)类第二线程做点什么，是吗？但我不知道如何将其转换为可运行的，因为一切都已经正常工作了。

我尝试删除“扩展线程”并插入“实现可运行”，但这只会给我错误。添加“扩展线程”和“实现可运行”都有效，但我怀疑这就是我必须做的

Answer 1

如果您不告诉我们错误消息的内容，那么任何人都很难告诉您错误消息的含义，但这里有一个猜测:

如果您除了将 SecondThread extends Thread 更改为 SecondThread Implements Runnable 之外什么也不做，那么 secondThread.start() 将无法编译，因为您的 SecondThread 类没有定义 start() 方法。

那么，给定一个 ... 实现 Runnable 对象，如何获得一个线程来运行它？

我建议您花一些时间学习 Java 并发教程。 https://docs.oracle.com/javase/tutorial/essential/concurrency/

我的问题的答案就在开头。