Question

我正在尝试使用ActionListener设置TextFields数组的文本。我已经设置了主类，并设置了ActionListener类。我相信我的问题是在我的主类中使用for循环生成多个JTextField来设置ActionListener，但我不确定。这是我的主要课程：包lab5.pkg2;

import java.awt.BorderLayout;
import java.awt.Panel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Lab52 
{

public static void main(String[] args) 
{
    JFrame frame = new JFrame();

    Panel nPanel = new Panel();
    frame.add(nPanel, BorderLayout.NORTH);
    Panel sPanel = new Panel();
    frame.add(sPanel, BorderLayout.SOUTH);

    JTextField[] tf = new JTextField[10];
    for(int k = 0; k < tf.length; k++)
    {
        tf[k] = new JTextField(4);
        nPanel.add(tf[k]);
    }
    RandListener listen = new RandListener(tf);

    JButton bRand = new JButton("Randomize");
    bRand.setActionCommand("bRand");
    bRand.addActionListener(listen);
    sPanel.add(bRand);
    JButton bMaxMin = new JButton("Max, Min");
    bRand.setActionCommand("bMaxMin");
    bRand.addActionListener(listen);
    sPanel.add(bMaxMin);

    frame.pack();
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}    
}

这是我的ActionListener类：

class RandListener implements ActionListener
{
private final JTextField[] tf = new JTextField[10]; 

public RandListener(JTextField[] tF)
{
    tf[0] = tF[0];
    tf[1] = tF[1];
    tf[2] = tF[2];
    tf[3] = tF[3];
    tf[4] = tF[4];
    tf[5] = tF[5];
    tf[6] = tF[6];
    tf[7] = tF[7];
    tf[8] = tF[8];
    tf[9] = tF[9];
}

@Override
public void actionPerformed(ActionEvent e) 
{
    if(e.getActionCommand().equals("bRand"))
    {
        for(int k = 0; k < 10; k++)
        {
            Random rNum = new Random();
            tf[k].setText(rNum.toString());
        }
    }
    if(e.getActionCommand().equals("bMaxMin"))
    {

    }
    else
    {
        JOptionPane.showMessageDialog(null, "Error");
    }
}

}

Answer 1

代码似乎现在正在运行;）我在代码中写了一些注释，其中包含了我已经改变的内容。

import java.awt.BorderLayout;
import java.awt.Panel;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Lab52 
{

public static void main(String[] args) 
{
    JFrame frame = new JFrame();

    Panel nPanel = new Panel();
    frame.add(nPanel, BorderLayout.NORTH);
    Panel sPanel = new Panel();
    frame.add(sPanel, BorderLayout.SOUTH);

    JTextField[] tf = new JTextField[10];
    for(int k = 0; k < tf.length; k++)
    {
        tf[k] = new JTextField(4);
        nPanel.add(tf[k]);
    }
    RandListener listen = new RandListener(tf);

    JButton bRand = new JButton("Randomize");
    bRand.setActionCommand("bRand");
    bRand.addActionListener(listen);
    sPanel.add(bRand);

    JButton bMaxMin = new JButton("Max, Min");
    bMaxMin.setActionCommand("bMaxMin"); // These 2 lines were refering to bRand, not to bMaxMin
    bMaxMin.addActionListener(listen); 
    sPanel.add(bMaxMin);

    frame.pack();
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}    
}

您的Listener类有一些简化 - 在构造函数中 - 在bRand的if中我生成一个随机整数，我不确定这是不是你的目标。

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.JOptionPane;
import javax.swing.JTextField;

class RandListener implements ActionListener
{
    private final JTextField[] tF;

    public RandListener(JTextField[] tF)
    {
        this.tF = tF; // I simplified your code here
    }

    @Override
    public void actionPerformed(ActionEvent e) 
    {
        if(e.getActionCommand().equals("bRand"))
        {
            for(int k = 0; k < tF.length; k++)
            {
                Random rNum = new Random();
                tF[k].setText(rNum.nextInt() + ""); // Not sure if you wanted a random number..
            }
        }
        if(e.getActionCommand().equals("bMaxMin"))
        {

        }
        else
        {
            JOptionPane.showMessageDialog(null, "Error");
        }
    }
}

使用ActionListener设置TextFields数组的文本

1 个答案: