JavaJFrame创建关闭应用程序的关闭按钮和清除所有文本字段并以新数量运行的重置按钮

Question

需要创建一个关闭按钮，关闭应用程序，并重置以清除字段并以新金额开始。 我添加的close按钮对代码没有多大作用，它只是复制了addInterest按钮函数

这是框架

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; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.JTextArea; 
import javax.swing.JTextField; 

public class InvestmentFrame extends JFrame { 
  private static final int FRAME_WIDTH = 400; 
  private static final int FRAME_HEIGHT = 250; 
  private static final int AREA_ROWS = 10; 
  private static final int AREA_COLUMNS = 30; 
  private static final double DEFAULT_RATE = 5; 
  private static final double INITIAL_BALANCE = 1000; 
  private JLabel rateLabel; 
  private JTextField rateField; 
  private JButton btnInterest, btnExit; 
  private JTextArea resultArea; 
  private double balance; 



  public InvestmentFrame() { 
    balance = INITIAL_BALANCE; 
    resultArea = new JTextArea(AREA_ROWS, AREA_COLUMNS); 
    resultArea.setText(balance + "\n"); 
    resultArea.setEditable(false); 
    this.createTextField(); 
    this.createButton(); 
    this.createPanel(); 

    this.setSize(FRAME_WIDTH, FRAME_HEIGHT); 

  } 

  private void createTextField() { 
    rateLabel = new JLabel("Interest Rate: "); 
    final int FIELD_WIDTH = 10; 
    rateField = new JTextField(FIELD_WIDTH); 
    rateField.setText("" + DEFAULT_RATE); 
  } 


  class AddInterestListener implements ActionListener { 
    @Override 
    public void actionPerformed(ActionEvent event) { 
      try { 
        double rate = Double.parseDouble(rateField.getText()); 
        if (rate < 0) { 
          throw new IllegalArgumentException(); 
        } 
        double interest = balance * rate / 100; 
        balance = balance + interest; 
        resultArea.append(balance + "\n"); 
      } catch (Exception exception) { 
        JOptionPane.showMessageDialog(null, "Rate is a positive floating-point number.", 
                                      "Invalid rate value entered!", JOptionPane.ERROR_MESSAGE); 
      } 
    } 
  } 

  private class CloseListener implements ActionListener{

    public void actionPerformed(ActionEvent e) {
      System.exit(0);

    }
  }

  private void createButton() { 
    btnInterest = new JButton("Add Interest"); 
    btnExit = new JButton("Close");

    ActionListener listener = new AddInterestListener(); 
    btnInterest.addActionListener(listener); 
    btnExit.addActionListener(listener); 
  } 

  private void createPanel() { 
    JPanel panel = new JPanel(); 
    panel.add(rateLabel); 
    panel.add(rateField); 
    panel.add(btnInterest); 
    panel.add(btnExit);
    JScrollPane scrollPane = new JScrollPane(resultArea); 
    panel.add(scrollPane); 
    this.add(panel); 
  }
}

这是观众

import javax.swing.JFrame;

/**
 This program shows the growth of an investment.
 */
public class InvestmentViewer {
  public static void main(String[] args)
  {
    JFrame frame = new InvestmentFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }

}

Answer 1

您没有将关闭侦听器添加到退出按钮。因此它不会关闭应用程序

ActionListener listener = new AddInterestListener(); 
btnInterest.addActionListener(listener); 
btnExit.addActionListener(listener); 

正确的方法：

btnExit.addActionListener(new CloseListener());