java - 将变量从一类传递到另一类

大家好，我很高兴，如果有人可以任何方式提供帮助，那就太好了。我正在使用eclipse，程序正在编译并运行。我有3个课程，它们在同一个程序包中。因此，我想将ThreadQuizCountdown类中的i值传递给其他类PanelQuizCountdown int，并将名称为timeField的JTextField当前显示在控制台中。这是代码

/**The driver class of the program. Here is the JFrame
 * class name RunQuizCountdown.java
 * @author Kiril Anastasov
 * @date 09/03/2012
 */

import java.awt.*;
import javax.swing.*;

public class RunQuizCountdown
{
    public static void main(String[] args)
    {

        JFrame application = new JFrame();
        PanelQuizCountdown panel = new PanelQuizCountdown();
        application.add(panel);
        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        application.setSize(200,300);
        application.setLocationByPlatform(true);
        application.setVisible(true);
    }

}



/** Here is the GUI of the program
 * class name PanelQuizCountdown.java
 * @author Kiril Anastasov
 * @date 09/03/2012
 */

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class PanelQuizCountdown extends JPanel implements ActionListener
{
    JTextField timeField, answerField;
    JLabel messageLabel, correctLabel, totalLabel;
    int x, y;
    int correct;
    int total;

    ThreadQuizCountdown myQuiz;

    PanelQuizCountdown()
    {
        timeField = new JTextField(5);
        myQuiz = new ThreadQuizCountdown(timeField);
        this.add(timeField);
        myQuiz.begin();


        messageLabel = new JLabel("What is the result of " + x + " * " + y);
        this.add(messageLabel);

        answerField = new JTextField(5);
        this.add(answerField);

        correctLabel = new JLabel("You gave : " + correct +  " correct answers");
        this.add(correctLabel);

        totalLabel = new JLabel("You answered: " + total + " questions");
        this.add(totalLabel);





    }


    public void actionPerformed(ActionEvent ae)
    {

    }
}

/** Here is the thread of the program
 * class name ThreadQuizCountdown.java
 * @author Kiril Anastasov
 * @date 09/03/2012
 */

import javax.swing.JTextField;

public class ThreadQuizCountdown implements Runnable
{
    JTextField  timeField;
    Thread myThread = new Thread(this);

    int i = 30;
    boolean go = true;

    ThreadQuizCountdown(JTextField theTimeField)
    {
        timeField = theTimeField;
    }

    public void run()
    {


        while(go)
        {
            System.out.println(i);

            try
            {
                myThread.sleep(1000);
            }
            catch (InterruptedException ie)
            {
                 System.out.println("thread exception");
            }

            timeField = new JTextField(26);

            if(i == 0 )
            {
                go = false;
            }
            i--;
        }

    }

    public void begin()
    {
        myThread.start();
    }

    public void finish()
    {
        myThread.stop();
    }
}

最佳答案

使用委托，将符合接口的委托类添加到begin（）方法参数中，例如

interface DelegationInterface {
   void countdownTick(int i);
}

在ThreadQuizCountdown中：
添加私有字段并修改begin方法：

private DelegationInterface delegate;

public void begin(DelegationInterface delegate) {
   this.delegate = delegate;
   myThread.start();
}

接下来，修改run（）：（请注意，我们在关键部分调用了倒数计时，在这种情况下这没关系，但是如果您有很多计时器，它将有助于避免问题）

public void run() {
....
  myThread.sleep(1000);
  if (delegate != null) {
      synchronized(delegate) {
          delegate.countdownTick(i);
      }
  }
....
}

最后，将接口的实现添加到面板中：

public class PanelQuizCountdown extends JPanel implements ActionListener, DelegationInterface {
    ....
    public void countdownTick(int i) {
        // place i to to timeField
    }
    ....
}

而已！

Begin

java - 将变量从一类传递到另一类