Question

我是java swing的新手。

当我想将actionlistener设置为其中一个按钮时，它必须获取textArea内容并将其发送到另一个类。它没有以我期望的方式工作。

相反，当我更改文本区域的内容时，它不起作用，我不知道发生了什么？

我命名为按钮的第一个按钮，当我在Button的动作侦测程序中使用另一个名为 Clac

的actionlistener时，会出现同样的问题

这是我的代码：

package FFT;

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

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

public class FFT_Main_Frame extends JFrame {

JLabel label;
JButton button;
TextPanel txtPanel;
JButton Button;
JLabel label1;
//JTextArea[] BoxArray;
makePolynomial mp;
JButton Calc;
Complex[] Nums;
Complex[] Result;
int input;
FFT_Main fft_main;
ShowResult shr;

public FFT_Main_Frame()
{
    super ("F F T");
    //final int input;
    label=new JLabel();
    txtPanel=new TextPanel();
    Button=new JButton("OK");

    label.setText("Please Enter your Polynomial Degree");
    setLayout(new FlowLayout());
    add(label);
    add(txtPanel);
    add(Button);

    Calc=new JButton("Claculate");



    Button.addActionListener(new ActionListener()
    {
        //Test t;

        //Integer content;
        @Override
        public void actionPerformed(ActionEvent arg0) {

            try{
            Integer   content=new   Integer(Integer.parseInt(txtPanel.getTextArea()));
            input=content;
            System.out.println(input);
            //inputt=input;
            mp=new makePolynomial(content);
            setLayout(new FlowLayout());
            add(mp);
            //setLayout(new BorderLayout());
            add(Calc);

            Nums=new Complex[input+1];
            Calc.addActionListener(new ActionListener()
            {
                @Override
                public void actionPerformed(ActionEvent arg0) {
                for(int i=input;i>=0;i--)
                    {
                        Nums[i]=new  Complex(Double.parseDouble(mp.BoxArray[2*(i+1)- 1].getText()),Double.parseDouble(mp.BoxArray[2*i].getText()));
                    }

                    for (int i=0;i<=input;i++)
                    {
                        System.out.println(Nums[i]);
                    }
                    fft_main=new FFT_Main();
                    Result=new Complex[input];

                    Result=fft_main.Recursive_FFT(Nums);

                    shr=new ShowResult(Result);

                    setLayout(new BorderLayout());
                    add(shr,BorderLayout.CENTER);

                    System.out.println("Result\n\n");
                    for (int i=0;i<=input;i++)
                    {
                        System.out.println(Result[i]);
                    }

                }
                });



            }
            catch (NumberFormatException exception)
            {
                JOptionPane.showMessageDialog(null, "Please Enter Just Numbers! " , "Wrong Value", JOptionPane.ERROR_MESSAGE);

            }
        }
    }
            );
    //Integer k=new Integer(Integer.parseInt(txtPanel.getTextArea()));
    //System.out.println();
    //Nums=new Complex[input+1];





    setSize(600,500);
    setVisible(true);






  }

}

makePolynomial class：

package FFT;

import java.awt.FlowLayout;

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;

public class makePolynomial extends JPanel{


  JLabel[] label;
  public JTextArea[] BoxArray;
  public static int l;
  public makePolynomial(int i)
  {
      //label=new JLabel();
      BoxArray=new JTextArea[2*(i+1)];
    label=new JLabel[i];
    l=i;
    setLayout(new FlowLayout());

     int b=i;
     for (int x=2*(i+1)-1;x>=0;x-=2)
    {
        BoxArray[x]=new JTextArea(1,3);
        BoxArray[x-1]=new JTextArea(1,3);
         add(BoxArray[x]);
         add(BoxArray[x-1]);

         if (b >=1)
         {
             label[b-1]=new JLabel();
             label[b-1].setText("<html>i X<sup>"+b+"</sup></html>");
            add(label[b-1]);
        }

        if(b==0)
         {
            JLabel l1=new JLabel();
             l1.setText("i");
             add(l1);
         }
         b--;
     }
 }

}

ShowResult类：

package FFT;

import java.awt.FlowLayout;

import javax.swing.JLabel;
import javax.swing.JPanel;

public class ShowResult extends JPanel {
JLabel[] label;


public ShowResult(Complex[] c) {


    label=new JLabel[c.length];
    System.out.println("Complex"+c.length);

    setLayout(new FlowLayout());

    for (int i=0;i<c.length;i++)
    {
        label[i]=new JLabel();
        label[i].setText("y["+i+"]= "+c[i].toString());

        add(label[i]);

    }




  }



  }

感谢您的帮助

Answer 1

作为代码较小部分的可运行程序的示例，请参见下文。为了简短起见，我已将makePolynomial类替换为JPanel。我添加了代码来隐藏actionPerformed Button方法中的三个初始组件，但我很确定有更好的方法可以做到这一点。

此程序是否可以按照您的预期在您的计算机上运行？

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

public class ActionListenerBug {
    public static void main(final String[] arguments) {
        SwingUtilities.invokeLater(() -> new ActionListenerBug().createAndShowGui());
    }

    private void createAndShowGui() {
        final JFrame frame = new JFrame("Stack Overflow");
        frame.setBounds(100, 100, 800, 600);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        final JPanel panel = new JPanel();

        JLabel label = new JLabel();
        // TextPanel is a class?
        JTextPane txtPanel = new JTextPane();
        JButton Button = new JButton("OK");

        label.setText("Please Enter your Polynomial Degree");

        panel.setLayout(new FlowLayout());
        panel.add(label);
        panel.add(txtPanel);
        panel.add(Button);

        Button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                try {
                    int input = Integer.parseInt(txtPanel.getText());
                    System.out.println(input);
                    //mp = new makePolynomial(content);
                    JPanel mp = new JPanel();
                    mp.add(new JLabel("input: " + input));

                    // Hide other components for now. Showing a different panel would be
                    // better.
                    label.setVisible(false);
                    txtPanel.setVisible(false);
                    Button.setVisible(false);

                    panel.setLayout(new FlowLayout());
                    panel.add(mp);
                    //setLayout(new BorderLayout());
                    JButton Calc = new JButton("Claculate");
                    panel.add(Calc);
                    panel.revalidate();
                } catch (NumberFormatException exception) {
                    JOptionPane.showMessageDialog(null, "Please Enter Just Numbers! ", 
                                                  "Wrong Value", 
                                                  JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        frame.getContentPane().add(panel);
        frame.setVisible(true);
    }
}

动作听众不起作用

1 个答案: