GUI银行账户Java

Question

我的存款和取款按钮有问题。我点击他们的时候他们什么也不做。

我的目标是让用户存款并从他们的帐户中提取。

抱歉，我是刚接触GUI的人。

带有存款和取款计算的bankAccount文件

public class bankAccount {  
    private double balance;

    public bankAccount() {   
        balance = 0;
    }

    public bankAccount(double initialBalance) {   
        balance = initialBalance;
    }

    public void deposit(double amount) {  
        double newBalance = balance + amount;
        balance = newBalance;
    }

    public void withdraw(double amount) {   
        double newBalance = balance - amount;
        balance = newBalance;
    }

    public double getBalance() {   
        return balance;
    }
}

我在actionPerformed方法的文件中遇到了问题。

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.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
class AccountPanel extends JPanel implements ActionListener {  
    private JLabel amountLabel, resultLabel;
    private JTextField amountTextField;   
    private JButton depositButton, withdrawButton;
    private bankAccount account;
    double result;

    public AccountPanel() {
        JPanel displayPanel = new JPanel(); 
        displayPanel.setLayout(new FlowLayout(FlowLayout.LEFT));

        amountLabel = new JLabel("Amount:"); 
        displayPanel.add(amountLabel);

        amountTextField = new JTextField(13); 
        displayPanel.add(amountTextField); 

        JPanel resultPanel = new JPanel(); 
        resultPanel.setLayout(new FlowLayout(FlowLayout.LEFT));

        resultLabel = new JLabel("Balance = "); 
        resultPanel.add(resultLabel);

        //buttons
        JPanel buttonPanel = new JPanel(); 
        buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));

        // deposit button 
        depositButton = new JButton("Deposit"); 
        buttonPanel.add(depositButton); 

        // withdraw
        withdrawButton = new JButton("Withdraw"); 
        buttonPanel.add(withdrawButton); 

        // add panels to main panel 
        this.setLayout(new BorderLayout()); 
        this.add(displayPanel, BorderLayout.WEST);
        this.add(resultPanel, BorderLayout.SOUTH); 
        this.add(buttonPanel, BorderLayout.EAST); 
    }



    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource(); 
        if (source == depositButton) {
            double dp = Double.parseDouble(amountTextField.getText());
            double dpamount = account.getBalance() + dp;
            account.deposit(dpamount);
            result = dpamount;
            resultLabel.setText("" + result);
            depositButton.addActionListener(this); 
        }
        else if (source == withdrawButton) { 
            double wd = Double.parseDouble(amountTextField.getText());
            account.withdraw(wd);
            resultLabel.setText("" + result);
            withdrawButton.addActionListener(this); 
        } 
   }
}

import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.Window;
import javax.swing.JFrame;
import javax.swing.JPanel;
class AccountFrame extends JFrame { 
    private static final int FRAME_WIDTH = 400;
    private static final int FRAME_HEIGHT = 100;

    public AccountFrame() { 
        setTitle("Bank Account"); 
        setSize(FRAME_WIDTH, FRAME_HEIGHT); 
        centerWindow(this); 
        setResizable(false); 
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        JPanel panel = new AccountPanel(); 
        this.add(panel); 
    } 

    private void centerWindow(Window w) { 
        Toolkit tk = Toolkit.getDefaultToolkit(); 
        Dimension d = tk.getScreenSize(); 
        setLocation((d.width-w.getWidth())/2, 
        (d.height-w.getHeight())/2); 
    } 
}

import javax.swing.*; 
public class Account{ 
    public static void main(String[] args) { 
        JFrame frame = new AccountFrame(); 
        frame.setVisible(true); 
    } 
} 

Answer 1

尝试这样做，而不是使用单个actionPerformed()方法：

注册事件处理程序(您错过了这一步)：

  depositButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent evt) {
       handleDepositButtonEvent(evt);
     }
  });

实现该事件的自定义事件处理程序：

  private void handleDepositButtonEvent(ActionEvent evt){
     double dp = Double.parseDouble(amountTextField.getText());
     double dpamount = account.getBalance() + dp;
     account.deposit(dpamount);
     result = dpamount;
     resultLabel.setText("" + result);
  }

对于要捕获的每个按钮和组件生成事件，都要这样做；单独的操作方法更容易阅读和维护。

顺便说一句，不要在动作监听器中添加动作监听器！这是没有道理的，而且无论如何也行不通。

if (source == depositButton) {
    double dp = Double.parseDouble(amountTextField.getText());
    ...
    depositButton.addActionListener(this); //<--- don't do this
} 

Answer 2

您没有将任何ActionListener注册到depositButton或withdrawButton。

在告诉我它们是在actionPerformed方法中注册之前，您必须意识到没有调用此方法，您不应该在这里注册您的ActionListener，或者至少由于您的原因，应该将它们添加到构造函数中，以便在程序运行时注册。

更详细地查看如何编写动作侦听器和如何使用按钮、复选框和单选按钮

Answer 3

depositButton.addActionListener(this)和withdrawButton.addActionListener(this)调用需要在AccountPanel构造函数中。现在，它们将永远不会被执行，因为按钮最初没有事件处理程序。