所以基本上我正在编写一个GUI程序，它使用JComboBox来显示各种财务公式。在显示公式方面，我已经掌握了一切，但这是我的问题。每次我在我的comboBox中选择一个新的公式时，其他的都会保持显示状态。我已经尝试编写一个if语句来禁用，删除和无效这些（不是所有的一次）但没有一个工作...我需要得到它所以当我点击一个选项时其他面板消失，如果有任何。谢谢！
这是完整的程序我遇到的问题是，当我选择一个新的公式时，我选择的那个仍然是活动的...我想要禁用或删除它。感谢。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.text.DecimalFormat;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class newFinanceFullClass extends JFrame {
private JMenu fileMenu;
private JMenuItem exitItem;
private JPanel presentValuePanel;
private JPanel financeFinderPanel;// A panel container
private JLabel principalMessage;
private JLabel yearlyRateMessage;
private JLabel termYearMessage;
private JPanel simpleInterestPanel;
private JPanel doublingTimePanel;
private JPanel compoundInterestPanel;
private JLabel NONEMessage;
private JLabel imageLabel;
private JLabel label;// A message to display
private JMenuBar menuBar;
private JTextField principalText; // To hold user input
private JButton calcButton; // Performs calculation
private final int WINDOW_WIDTH = 600; // Window width
private final int WINDOW_HEIGHT = 600; // Window height
private JTextField yearlyRateText;
private JTextField termYearText;
DecimalFormat dc =new DecimalFormat("####0.00"); //formater
private JComboBox financeBox;
double principal = 400.0;
double yearlyRate = .04;
double termYears = 4.0;
private String[] financeFormulas = { "NONE", "Present value", "Simple interest",
"Doubling time", "Compound interest", "Decaf"};
financeFormulaClass financeFormula = new financeFormulaClass(principal, yearlyRate, termYears);
/**
* Constructor
*/
public newFinanceFullClass()
{
// Call the JFrame constructor.
super("Finance Class");
// Set the size of the window.
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
// Specify what happens when the close
// button is clicked.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Build the panel and add it to the frame.
financeFinderPanel();
setLayout(new BorderLayout());
//buildPanel();
menuBar = new JMenuBar();
buildFileMenu();
menuBar.add(fileMenu);
setJMenuBar(menuBar);
// Add the panel to the frame's content pane.
add(financeFinderPanel);
//add(panel);
// Display the window.
setVisible(true);
}
private void financeFinderPanel()
{
// Create a panel to hold the combo box.
financeFinderPanel = new JPanel();
//create label
label = new JLabel("Pick your formula");
ImageIcon funnyImage = new ImageIcon("funny.gif");
imageLabel = new JLabel();
imageLabel.setLocation(50, 55);
label.setForeground(Color.BLUE);
// Create the combo box
financeBox = new JComboBox(financeFormulas);
imageLabel.setIcon(funnyImage);
// Register an action listener.
financeBox.addActionListener(new financeBoxListener());
exitItem = new JMenuItem("Exit");
exitItem.setMnemonic(KeyEvent.VK_X);
// Add the combo box to the panel.
financeFinderPanel.add(financeBox);
financeFinderPanel.add(label);
financeFinderPanel.add(imageLabel);
}
/** private void menuList(){
exitItem = new JMenuItem("Exit");
exitItem.setMnemonic(KeyEvent.VK_X);
menuList.add(exitItem);
} **/
private void buildMenuBar()
{
// Create the menu bar.
menuBar = new JMenuBar();
// Create the file and text menus.
buildFileMenu();
// buildTextMenu();
// Add the file and text menus to the menu bar.
menuBar.add(fileMenu);
//menuBar.add(textMenu);
// Set the window's menu bar.
setJMenuBar(menuBar);
}
private void buildFileMenu()
{
// Create an Exit menu item.
exitItem = new JMenuItem("Exit");
exitItem.setMnemonic(KeyEvent.VK_X);
exitItem.addActionListener(new ExitListener());
// Create a JMenu object for the File menu.
fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
// Add the Exit menu item to the File menu.
fileMenu.add(exitItem);
}
private void presentValuePanel()
{
// Create the label, text field, and button components.
principalMessage = new JLabel("principal");
principalText = new JTextField(10);
yearlyRateMessage = new JLabel("Yearly Rate");
yearlyRateText = new JTextField(10);
termYearMessage = new JLabel("Term Year");
termYearText = new JTextField(10);
calcButton = new JButton("Calc Present Value");
// Add an action listener to the button.
//calcButton.addActionListener(new CalcButtonListener());
calcButton.addActionListener(new financeFormListener());
// Create a panel to hold the components.
presentValuePanel = new JPanel();
// Add the label, text field, and button to the panel.
presentValuePanel.add(principalMessage);
presentValuePanel.add(principalText);
presentValuePanel.add(yearlyRateMessage);
presentValuePanel.add(yearlyRateText);
presentValuePanel.add(termYearMessage);
presentValuePanel.add(termYearText);
presentValuePanel.add(calcButton);
}
private void simpleInterestPanel(){
principalMessage = new JLabel("principal");
principalText = new JTextField(10);
yearlyRateMessage = new JLabel("Yearly Rate");
yearlyRateText = new JTextField(10);
termYearMessage = new JLabel("Term Year");
termYearText = new JTextField(10);
calcButton = new JButton("Calc Simple Interest");
simpleInterestPanel = new JPanel();
calcButton.addActionListener(new financeFormListener());
simpleInterestPanel.add(principalMessage);
simpleInterestPanel.add(principalText);
simpleInterestPanel.add(yearlyRateMessage);
simpleInterestPanel.add(yearlyRateText);
simpleInterestPanel.add(termYearMessage);
simpleInterestPanel.add(termYearText);
simpleInterestPanel.add(calcButton);
}
private void doublingTimePanel(){
yearlyRateMessage = new JLabel("Yearly Rate");
yearlyRateText = new JTextField(10);
calcButton = new JButton("Calc Doubling Time");
calcButton.addActionListener(new financeFormListener());
doublingTimePanel = new JPanel();
doublingTimePanel.add(yearlyRateMessage);
doublingTimePanel.add(yearlyRateText);
doublingTimePanel.add(calcButton);
}
private void compoundInterestPanel(){
principalMessage = new JLabel("principal");
principalText = new JTextField(10);
yearlyRateMessage = new JLabel("Yearly Rate");
yearlyRateText = new JTextField(10);
termYearMessage = new JLabel("Term Year");
termYearText = new JTextField(10);
calcButton = new JButton("Calc Compound Interest");
compoundInterestPanel = new JPanel();
calcButton.addActionListener(new financeFormListener());
compoundInterestPanel.add(principalMessage);
compoundInterestPanel.add(principalText);
compoundInterestPanel.add(yearlyRateMessage);
compoundInterestPanel.add(yearlyRateText);
compoundInterestPanel.add(termYearMessage);
compoundInterestPanel.add(termYearText);
compoundInterestPanel.add(calcButton);
}
//Listener to choose which formula
private class financeBoxListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
Object actionCommand = e.getSource();
String selection = (String) financeBox.getSelectedItem();
if(selection.equals("Present value")){
//financeFinderPanel.removeAll();
presentValuePanel();
add(presentValuePanel, BorderLayout.SOUTH);
pack();
}
else if(selection.equals("Simple interest")){
simpleInterestPanel();
add(simpleInterestPanel, BorderLayout.NORTH);
pack();
}
else if(selection.equals("Doubling time")){
doublingTimePanel();
add(doublingTimePanel, BorderLayout.SOUTH);
pack();
}
else if(selection.equals("Compound interest")){
compoundInterestPanel();
add(compoundInterestPanel, BorderLayout.NORTH);
pack();
}
else if(selection.equals("NONE")){
setSize(200, 150);
financeFinderPanel();
add(financeFinderPanel, BorderLayout.NORTH);
NONEMessage = new JLabel("PICK A SELECTION");
}
}
}
private class financeFormListener implements ActionListener{
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String actionCommand = e.getActionCommand();
if(actionCommand.equals("Calc Simple Interest")){
try{
double principal = Double.parseDouble(principalText.getText());
double yearlyRate = Double.parseDouble(yearlyRateText.getText());
double termYears = Double.parseDouble(termYearText.getText());
double interestRate = (principal * yearlyRate * termYears);
String msg = "Simple interest is: $" + dc.format(interestRate);
JOptionPane.showMessageDialog(null, msg);
}
catch(NumberFormatException r){
JOptionPane.showMessageDialog(null, "Please insert formula information");
}
}
else if(actionCommand.equals("Calc Present Value"))
{
try{
double principal = Double.parseDouble(principalText.getText());
double yearlyRate = Double.parseDouble(yearlyRateText.getText());
double termYears = Double.parseDouble(termYearText.getText());
double pValue = financeFormula.presentValue(principal, yearlyRate, termYears);
//double pValue = principal * (((1- Math.pow(1 + yearlyRate, -termYears))/ yearlyRate));
String msg = "Present value is: $" + dc.format(pValue);
JOptionPane.showMessageDialog(null, msg);
}
catch(NumberFormatException r){
JOptionPane.showMessageDialog(null, "Please insert formula information");
}
}
else if(actionCommand.equals("Calc Doubling Time")){
try{
double yearlyRate = Double.parseDouble(yearlyRateText.getText());
double dValue = financeFormula.doublingTime(yearlyRate);
String msg = "Doubling Time is: " + dc.format(dValue);
JOptionPane.showMessageDialog(null, msg);
}
catch(NumberFormatException r){
JOptionPane.showMessageDialog(null, "Please insert formula information");
}
}
else if(actionCommand.equals("Calc Compound Interest")){
try{
double principal = Double.parseDouble(principalText.getText());
double yearlyRate = Double.parseDouble(yearlyRateText.getText());
double termYears = Double.parseDouble(termYearText.getText());
double compoundInterest = financeFormula.compoundInterest(principal, yearlyRate, termYears);
String msg = "Compound Interest is: $" + dc.format(compoundInterest);
JOptionPane.showMessageDialog(null, msg);
}
catch(NumberFormatException r){
JOptionPane.showMessageDialog(null, "Please insert formula information");
}
}
}
}
private class ExitListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
}
public static void main(String[] args)
{
new newFinanceFullClass();
}
}
答案 0 :(得分：1)
再次使用CardLayout帮助您交换JPanel。您将创建一个JPanel并将其布局设置为CardLayout，然后您将使用String常量添加要转换到此持有者JPanel的JPanels（“卡片”），您将传递到CardLayout的{{1允许它交换组件的方法。
例如，假设您有一个枚举来保存您的财务公式字符串，类似于：
show(...)然后可以设置CardLayout及其JPanel：
public enum FinanceFormula {
NONE("NONE"),
PRESENT_VALUE("Present value"),
SIMPLE_INTEREST("Simple interest"),
DOUBLING_TIME("Doubling time"),
COMPOUND_INTEREST("Compound interest"),
DECAF("Decaf");
private String name;
private FinanceFormula(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public String toString() {
return getName();
};
}
和JComboBox如下。这是有效的，因为我已经将枚举重写为String方法，以便显示正确的名称：
private CardLayout cardLayout = new CardLayout();
private JPanel cardHolderPanel = new JPanel(cardLayout);
然后，您将使用从枚举中获取的字符串常量将所有公式JPanels添加到cardHolderPanel中：
private JComboBox<FinanceFormula> comboBox = new JComboBox<>(FinanceFormula.values());
然后当你想要交换JPanels时，只需将相应的String传递给CardLayout的show方法，你就可以了：
// fill the cardHolderPanel with "cards", JPanels with formula:
cardHolderPanel.add(createNonePanel(), FinanceFormula.NONE.getName());
cardHolderPanel.add(createPresentValuePanel(), FinanceFormula.PRESENT_VALUE.getName());
cardHolderPanel.add(createSimpleInterestPanel(), FinanceFormula.SIMPLE_INTEREST.getName());
cardHolderPanel.add(createDoublingTimePanel(), FinanceFormula.DOUBLING_TIME.getName());
cardHolderPanel.add(createCompoundInterestPanel(), FinanceFormula.COMPOUND_INTEREST.getName());
cardHolderPanel.add(createDecafPanel(), FinanceFormula.DECAF.getName());
以下程序不会创建任何花哨的公式JPanels，但它没有必要，因为它是一个MCVE，用于演示仅交换JPanel：
private void combBoxActionPerformed(ActionEvent e) {
FinanceFormula selectedFormula = (FinanceFormula) comboBox.getSelectedItem();
cardLayout.show(cardHolderPanel, selectedFormula.getName());
}