public class ATMgui extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 1L;
public static final int WIDTH = 500;
public static final int HEIGHT = 200;
private ATMbizlogic theBLU;// short for the Business Logic Unit
public JLabel totalBalanceLabel;
public JTextField withdrawTextField;
public JTextField depositTextField;
public JTextField pinTextField;
/**
* Creates a new instance of ATMgui
*/
public ATMgui() {
setTitle("ATM Transactions");
setSize(WIDTH, HEIGHT);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
Container contentPane = getContentPane();
contentPane.setBackground(Color.BLACK);
contentPane.setLayout(new BorderLayout());
// Do the panel for the rest stop
JLabel start = new JLabel("Welcome To Your Account", JLabel.CENTER);
Font curFont = start.getFont();
start.setFont(new Font(curFont.getFontName(), curFont.getStyle(), 25));
start.setForeground(Color.BLUE);
start.setOpaque(true);
start.setBackground(Color.BLACK);
pinTextField = new JTextField();
JLabel pinLabel = new JLabel("Enter your PIN below:", JLabel.CENTER);
pinLabel.setForeground(Color.RED);
pinLabel.setOpaque(true);
pinLabel.setBackground(Color.WHITE);
JButton pinButton = new JButton("Enter Pin OK");
pinButton.addActionListener(this);
pinButton.setBackground(Color.red);
JPanel pinPanel = new JPanel();
pinPanel.setLayout(new GridLayout(3, 1, 100, 0));
pinPanel.add(pinLabel);
pinPanel.add(pinTextField);
pinPanel.add(pinButton);
contentPane.add(pinPanel, BorderLayout.WEST);
JPanel headingPanel = new JPanel();
headingPanel.setLayout(new GridLayout());
headingPanel.add(start);
contentPane.add(headingPanel, BorderLayout.NORTH);
// Do the panel for the amount & type of transactions
withdrawTextField = new JTextField();
JLabel withdrawLabel = new JLabel("Withdraw (0.00)", JLabel.CENTER);
withdrawLabel.setForeground(Color.RED);
withdrawLabel.setOpaque(true);
withdrawLabel.setBackground(Color.WHITE);
depositTextField = new JTextField();
JLabel depositLabel = new JLabel("Deposit (0.00)", JLabel.CENTER);
depositLabel.setForeground(Color.RED);
depositLabel.setOpaque(true);
depositLabel.setBackground(Color.WHITE);
JButton txButton = new JButton("Transactions OK");
txButton.addActionListener(this);
txButton.setBackground(Color.red);
JPanel txPanel = new JPanel();
txPanel.setLayout(new GridLayout(5, 1, 30, 0));
txPanel.add(withdrawLabel);
txPanel.add(withdrawTextField);
txPanel.add(depositLabel);
txPanel.add(depositTextField);
txPanel.add(txButton);
contentPane.add(txPanel, BorderLayout.EAST);
txPanel.setVisible(true);
totalBalanceLabel = new JLabel("Your balance after transactions: ", JLabel.CENTER);
totalBalanceLabel.setForeground(Color.BLUE);
totalBalanceLabel.setOpaque(true);
totalBalanceLabel.setBackground(Color.BLACK);
contentPane.add(totalBalanceLabel, BorderLayout.SOUTH);
theBLU = new ATMbizlogic();
}
public void actionPerformed(ActionEvent e) {
String actionCommand = e.getActionCommand();
// Container contentPane = getContentPane();
if (actionCommand.equals("Transactions OK")) {
try {
double deposit = Double.parseDouble(depositTextField.getText().trim());
double withdraw = Double.parseDouble(withdrawTextField.getText().trim());
theBLU.computeBalance(withdraw, deposit);
totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());
} catch (ATMexception ex) {
totalBalanceLabel.setText("Error: " + ex.getMessage());
} catch (Exception ex) {
totalBalanceLabel.setText("Error in deposit or withdraw amount: " + ex.getMessage());
}
} else if (actionCommand.equals("Enter Pin OK")) {
try {
double pin = Double.parseDouble(pinTextField.getText().trim());
theBLU.checkPin(pin);
totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());
} catch (ATMexception ex) {
totalBalanceLabel.setText("Error: " + ex.getMessage());
} catch (Exception ex) {
totalBalanceLabel.setText("Error in pin: " + ex.getMessage());
}
} else {
System.out.println("Error in button interface.");
}
}
public static void main(String[] args) {
ATMgui gui = new ATMgui();
gui.setVisible(true);
}
}
答案 0 :(得分：2)
我认为这不是为按钮实现ActionListeners的正确方法。
public void actionPerformed(ActionEvent e)
{
String actionCommand = e.getActionCommand();
// Container contentPane = getContentPane();
if (actionCommand.equals("Transactions OK"))
else ...
}
使用actionPerformed方法中的if-else stamements，每次按下任何按钮时，程序都会被强制检查要调用的侦听器，这样，您的代码就不容易编辑和重用。 此外，GUI容器就像一个事件的接收者，然后你应该避免
pinButton.addActionListener(this);
尝试为每个按钮实现自己的内部类，如下所示：
JButton pinButton = new JButton("Enter Pin OK");
pinButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae){
//enter here your action
txPanel.setVisible(true);
}
});
通过这种方式，您不需要为您的类实现ActionListener接口，因为您正在为pinButton实现接口的内部功能。检查SO的this old question。
此外，您应该避免在类构造函数中实现所有GUI元素，最好在单独的方法中实现GUI，例如createAndShowGui()，并在构造函数中调用它，以尊重Java Swing conventions和在不同的线程中运行Swing组件，称为Event Dispatch Thread，与应用程序的主线程不同。阅读this question。
然后在txPanel.setVisible(false);方法中加入createAndShowGui()。
请记住，Swing组件不是线程安全的。
答案 1 :(得分：1)
由于您粘贴的代码不起作用，我已经为您制作了一个小程序，看一看，看看您可以做些什么更改以便将其合并到您的案例中：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PanelTest extends JFrame
{
private JPanel eastPanel;
public PanelTest()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationByPlatform(true);
Container container = getContentPane();
eastPanel = new JPanel();
eastPanel.setBackground(Color.DARK_GRAY);
JPanel westPanel = new JPanel();
westPanel.setBackground(Color.YELLOW);
JPanel centerPanel = new JPanel();
centerPanel.setBackground(Color.BLUE);
container.add(eastPanel, BorderLayout.LINE_START);
container.add(centerPanel, BorderLayout.CENTER);
container.add(westPanel, BorderLayout.LINE_END);
eastPanel.setVisible(false);
JButton showButton = new JButton("Click Me to Display EAST JPanel");
showButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
eastPanel.setVisible(true);
}
});
JButton hideButton = new JButton("Click Me to Hide EAST JPanel");
hideButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
eastPanel.setVisible(false);
}
});
container.add(hideButton, BorderLayout.PAGE_START);
container.add(showButton, BorderLayout.PAGE_END);
setSize(300, 300);
setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new PanelTest();
}
});
}
}
从以后开始，永远不要将NORTH，EAST，WEST和SOUTH用于BorderLayout。它们已分别替换为PAGE_START，LINE_START，LINE_END和PAGE_END。
BorderLayout对象有五个区域。这些区域由BorderLayout常量指定：
版本说明： 在JDK 1.4版之前，各个区域的首选名称是不同的，从罗盘的点（例如，顶部区域的BorderLayout.NORTH）到我们在示例中使用的常量的更多版本。我们的示例使用的常量是首选，因为它们是标准的，并使程序能够适应具有不同方向的语言。
我修改了checkPin(...)类的ATMLogin方法以返回boolean而不是void，因此在actionPerformed(...)方法中ATMgui 1}} class，如果这个东西返回true，那么只是将所需的JPanel设置为可见，否则什么都不做。
请检查代码并查看您可以采取哪些更改，以使其适用于您的目的。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ATMgui extends JFrame implements ActionListener
{
/**
*
*/
private static final long serialVersionUID = 1L;
public static final int WIDTH = 500;
public static final int HEIGHT = 200;
private ATMbizlogic theBLU;// short for the Business Logic Unit
private JPanel txPanel;
public JLabel totalBalanceLabel;
public JTextField withdrawTextField;
public JTextField depositTextField;
public JTextField pinTextField;
/**
* Creates a new instance of ATMgui
*/
public ATMgui()
{
setTitle("ATM Transactions");
setSize(WIDTH, HEIGHT);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
Container contentPane = getContentPane();
contentPane.setBackground(Color.BLACK);
contentPane.setLayout(new BorderLayout());
// Do the panel for the rest stop
JLabel start = new JLabel("Welcome To Your Account", JLabel.CENTER);
Font curFont = start.getFont();
start.setFont(new Font(curFont.getFontName(), curFont.getStyle(), 25));
start.setForeground(Color.BLUE);
start.setOpaque(true);
start.setBackground(Color.BLACK);
pinTextField = new JTextField();
JLabel pinLabel = new JLabel("Enter your PIN below:", JLabel.CENTER);
pinLabel.setForeground(Color.RED);
pinLabel.setOpaque(true);
pinLabel.setBackground(Color.WHITE);
JButton pinButton = new JButton("Enter Pin OK");
pinButton.addActionListener(this);
pinButton.setBackground(Color.red);
JPanel pinPanel = new JPanel();
pinPanel.setLayout(new GridLayout(3, 1, 100, 0));
pinPanel.add(pinLabel);
pinPanel.add(pinTextField);
pinPanel.add(pinButton);
contentPane.add(pinPanel, BorderLayout.WEST);
JPanel headingPanel = new JPanel();
headingPanel.setLayout(new GridLayout());
headingPanel.add(start);
contentPane.add(headingPanel, BorderLayout.NORTH);
// Do the panel for the amount & type of transactions
withdrawTextField = new JTextField();
JLabel withdrawLabel = new JLabel("Withdraw (0.00)", JLabel.CENTER);
withdrawLabel.setForeground(Color.RED);
withdrawLabel.setOpaque(true);
withdrawLabel.setBackground(Color.WHITE);
depositTextField = new JTextField();
JLabel depositLabel = new JLabel("Deposit (0.00)", JLabel.CENTER);
depositLabel.setForeground(Color.RED);
depositLabel.setOpaque(true);
depositLabel.setBackground(Color.WHITE);
JButton txButton = new JButton("Transactions OK");
txButton.addActionListener(this);
txButton.setBackground(Color.red);
txPanel = new JPanel();
txPanel.setLayout(new GridLayout(5, 1, 30, 0));
txPanel.add(withdrawLabel);
txPanel.add(withdrawTextField);
txPanel.add(depositLabel);
txPanel.add(depositTextField);
txPanel.add(txButton);
contentPane.add(txPanel, BorderLayout.EAST);
txPanel.setVisible(false);
totalBalanceLabel = new JLabel("Your balance after transactions: ", JLabel.CENTER);
totalBalanceLabel.setForeground(Color.BLUE);
totalBalanceLabel.setOpaque(true);
totalBalanceLabel.setBackground(Color.BLACK);
contentPane.add(totalBalanceLabel, BorderLayout.SOUTH);
theBLU = new ATMbizlogic();
}
public void actionPerformed(ActionEvent e)
{
String actionCommand = e.getActionCommand();
// Container contentPane = getContentPane();
if (actionCommand.equals("Transactions OK"))
{
try
{
double deposit = Double.parseDouble(depositTextField.getText().trim());
double withdraw = Double.parseDouble(withdrawTextField.getText().trim());
theBLU.computeBalance(withdraw, deposit);
totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());
}
/*catch (ATMexception ex)
{
totalBalanceLabel.setText("Error: " + ex.getMessage());
}*/
catch (Exception ex)
{
totalBalanceLabel.setText("Error in deposit or withdraw amount: " + ex.getMessage());
}
}
else if (actionCommand.equals("Enter Pin OK"))
{
try
{
double pin = Double.parseDouble(pinTextField.getText().trim());
if(theBLU.checkPin(pin))
txPanel.setVisible(true);
totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());
}
/*catch (ATMexception ex)
{
totalBalanceLabel.setText("Error: " + ex.getMessage());
}*/
catch (Exception ex)
{
totalBalanceLabel.setText("Error in pin: " + ex.getMessage());
ex.printStackTrace();
}
}
else
{
System.out.println("Error in button interface.");
}
}
public static void main(String[] args)
{
ATMgui gui = new ATMgui();
gui.setVisible(true);
}
}
class ATMbizlogic
{
private double totalBalance;
private boolean rightPinEntered;
/**
* Creates a new instance of ATMbizlogic
*/
public ATMbizlogic()
{
totalBalance = 0.0;
rightPinEntered = true;
}
public void computeBalance(double withdraw, double deposit)
//throws ATMexception
{
if(withdraw <=0)
{
System.out.println("Negative withdraw not allowed");
//throw new ATMexception("Negative withdraw not allowed");
}
if(deposit <=0)
{
System.out.println("Negative deposit not allowed");
//throw new ATMexception("Negative deposit not allowed");
}
double balance = deposit - withdraw;
totalBalance = totalBalance + balance;
}
public boolean checkPin(double pin)
//throws ATMexception
{
if(pin <=0)
{
System.out.println("Negative pin not allowed");
rightPinEntered = false;
//throw new ATMexception("Negative pin not allowed");
}
/*else if(rightPinEntered == false)
{
System.out.println("Can not take another pin");
rightPinEntered = false;
//throw new ATMexception("Can not take another pin");
}*/
else if(pin<1111 || pin>9999)
{
System.out.println("Enter a valid pin");
rightPinEntered = false;
//throw new ATMexception("Enter a valid pin");
}
else
{
rightPinEntered = true;
}
return rightPinEntered;
}
public double getBalance()
{
return totalBalance;
}
}