删除Java面板而不会使程序崩溃
因此，基本上我正在编写一个GUI程序，它使用JComboBox来显示各种金融公式。我已经准备好了显示公式的一切，但这是我的问题。每次我在组合框中选择一个新公式时，其他公式都会显示出来。我试着写一个if语句来禁用、删除和失效这些（不是一次全部），但是没有一个有效…我需要得到它，这样当我点击一个选项时，其他面板就会消失，如果有的话。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，我在它仍然有效之前选择的公式…我想禁用或删除它。谢谢删除Java面板而不会使程序崩溃,java,swing,Java,Swing,因此，基本上我正在编写一个GUI程序，它使用JComboBox来显示各种金融公式。我已经准备好了显示公式的一切，但这是我的问题。每次我在组合框中选择一个新公式时，其他公式都会显示出来。我试着写一个if语句来禁用、删除和失效这些（不是一次全部），但是没有一个有效…我需要得到它，这样当我点击一个选项时，其他面板就会消失，如果有的话。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，我在它仍然有效之前选择的公式…我想禁用或删除它。谢谢 import java.awt.BorderLayou
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();
}
}
同样，使用CardLayout来帮助您交换JPanel。您将创建一个JPanel并将其布局设置为CardLayout，然后使用字符串常量将您希望交换的JPanel（“卡”）添加到此持有者JPanel中，字符串将传递到CardLayout的
show（…）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();
};
}
private CardLayout cardLayout = new CardLayout();
private JPanel cardHolderPanel = new JPanel(cardLayout);
private JComboBox<FinanceFormula> comboBox = new JComboBox<>(FinanceFormula.values());
private void combBoxActionPerformed(ActionEvent e) {
FinanceFormula selectedFormula = (FinanceFormula) comboBox.getSelectedItem();
cardLayout.show(cardHolderPanel, selectedFormula.getName());
}
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
@SuppressWarnings("serial")
public class NewFinance2 extends JPanel {
private CardLayout cardLayout = new CardLayout();
private JPanel cardHolderPanel = new JPanel(cardLayout);
private JComboBox<FinanceFormula> comboBox = new JComboBox<>(FinanceFormula.values());
public NewFinance2() {
// 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());
comboBox.addActionListener(e -> combBoxActionPerformed(e));
JPanel northPanel = new JPanel();
northPanel.add(comboBox);
setLayout(new BorderLayout());
add(cardHolderPanel, BorderLayout.CENTER);
add(northPanel, BorderLayout.NORTH);
}
private void combBoxActionPerformed(ActionEvent e) {
FinanceFormula selectedFormula = (FinanceFormula) comboBox.getSelectedItem();
cardLayout.show(cardHolderPanel, selectedFormula.getName());
}
// A bunch of dummy methods that don't create much
// Your real methods would create more complex JPanels
private JPanel createDecafPanel() {
return createPanel(FinanceFormula.DECAF);
}
private JPanel createCompoundInterestPanel() {
return createPanel(FinanceFormula.COMPOUND_INTEREST);
}
private JPanel createDoublingTimePanel() {
return createPanel(FinanceFormula.DOUBLING_TIME);
}
private JPanel createSimpleInterestPanel() {
return createPanel(FinanceFormula.SIMPLE_INTEREST);
}
private JPanel createPresentValuePanel() {
return createPanel(FinanceFormula.PRESENT_VALUE);
}
private JPanel createNonePanel() {
return createPanel(FinanceFormula.NONE);
}
// temporary method just for demonstration purposes
private JPanel createPanel(FinanceFormula financeFormula) {
JLabel label = new JLabel(financeFormula.getName());
label.setFont(label.getFont().deriveFont(Font.BOLD, 24f));
JPanel panel = new JPanel(new GridBagLayout());
panel.add(label);
panel.setPreferredSize(new Dimension(400, 300));
float split = 0.7f;
float h = (float) (split + Math.random() * (1f - split));
float s = (float) (split + Math.random() * (1f - split));
float b = (float) (split + Math.random() * (1f - split));
Color color = Color.getHSBColor(h, s, b);
panel.setBackground(color);
return panel;
}
private static void createAndShowGui() {
NewFinance2 mainPanel = new NewFinance2();
JFrame frame = new JFrame("Finance");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
导入java.awt.BorderLayout；
导入java.awt.CardLayout；
导入java.awt.Color；
导入java.awt.Dimension；
导入java.awt.Font；
导入java.awt.GridBagLayout；
导入java.awt.event.ActionEvent；
导入javax.swing.*；
@抑制警告（“串行”）
公共类新金融2扩展JPanel{
private CardLayout CardLayout=新的CardLayout（）；
专用JPanel卡面板=新JPanel（卡布局）；
private JComboBox comboBox=新的JComboBox（FinanceFormula.values（））；
公共新金融2（）{
//用“卡”填充持卡人面板，用公式填充JPanels：
添加（createNonePanel（），FinanceFormula.NONE.getName（））；
添加（createPresentValuePanel（），FinanceFormula.PRESENT_VALUE.getName（））；
添加（createSimpleInterestPanel（），FinanceFormula.SIMPLE_INTEREST.getName（））；
添加（createDoublingTimePanel（），FinanceFormula.DOUBLING_TIME.getName（））；
添加（createCompoundInterestPanel（），FinanceFormula.composite_INTEREST.getName（））；
add（createDecafPanel（），FinanceFormula.DECAF.getName（））；
comboBox.addActionListener（e->ComboxActionPerformed（e））；
JPanel northPanel=新的JPanel（）；
添加（组合框）；
setLayout（新的BorderLayout（））；
添加（面板、边框布局、中心）；
添加（northPanel，BorderLayout.NORTH）；
}
已执行的私有操作（操作事件e）{
FinanceFormula selectedFormula=（FinanceFormula）组合框。getSelectedItem（）；
显示（持卡人面板，selectedFormula.getName（））；
}
//一堆不会产生太多结果的伪方法
//您的实际方法将创建更复杂的JPanel
私有JPanel createDecafPanel（）{
返回createPanel（FinanceFormula.DECAF）；
}
私有JPanel CreateCompondinInterestPanel（）{
返回createPanel（FinanceFormula.复利）；
}
私有JPanel createDoublingTimePanel（）{
返回createPanel（FinanceFormula.倍增时间）；
}
私有JPanel createSimpleInterestPanel（）{
返回createPanel（FinanceFormula.单利）；
}
私有JPanel createPresentValuePanel（）{
返回createPanel（FinanceFormula.现值）；
}
私有JPanel createNonePanel（）{
返回createPanel（FinanceFormula.NONE）；
}
//仅用于演示目的的临时方法
私人JPanel createPanel（金融公式金融公式）{
JLabel=新的JLabel（financeFormula.getName（））；
label.setFont（label.getFont（）.deriveFont（Font.BOLD，24f））；
JPanel panel=newjpanel（newgridbagloayout（））；
面板。添加（标签）；
面板。设置首选尺寸（新尺寸（400300））；
浮动分割=0.7f；
浮点h=（浮点）（拆分+数学随机（）*（1f-拆分））；
float s=（float）（split+Math.random（）*（1f-split））；
float b=（float）（split+Math.random（）*（1f-split））；
Color Color=Color.getHSBColor（h、s、b）；
面板.立根背景（颜色）；
返回面板；
}
私有静态void createAndShowGui（）{
NewFinance2主面板=new NewFinance2（）；
JFrame=新JFrame（“财务”）；
frame.setDefaultCloseOperation（JFrame.DISPOSE_ON_CLOSE）；
frame.getContentPane（）.add（主面板）；
frame.pack（）；
frame.setLocationByPlatform（真）；
frame.setVisible（true）；
}
公共静态void main（字符串[]args）{
调用器（（）->createAndShowGui（））；
}
}
==来比较字符串=。请改用equals（…）
或equalsIgnoreCase（…）
方法。了解==
检查两个对象引用是否相同，这不是您感兴趣的。另一方面，这些方法检查两个字符串是否具有相同顺序的相同字符，这就是这里的问题所在。另一方面，您应该使用a交换组件。当我单击一个新字符串时，是否有人可以简单地删除它们？对不起，我不确定您的意思。你的意思是移除一个JPanel并在其位置上不显示任何内容吗？如果是这样的话，你就是你
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
@SuppressWarnings("serial")
public class NewFinance2 extends JPanel {
private CardLayout cardLayout = new CardLayout();
private JPanel cardHolderPanel = new JPanel(cardLayout);
private JComboBox<FinanceFormula> comboBox = new JComboBox<>(FinanceFormula.values());
public NewFinance2() {
// 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());
comboBox.addActionListener(e -> combBoxActionPerformed(e));
JPanel northPanel = new JPanel();
northPanel.add(comboBox);
setLayout(new BorderLayout());
add(cardHolderPanel, BorderLayout.CENTER);
add(northPanel, BorderLayout.NORTH);
}
private void combBoxActionPerformed(ActionEvent e) {
FinanceFormula selectedFormula = (FinanceFormula) comboBox.getSelectedItem();
cardLayout.show(cardHolderPanel, selectedFormula.getName());
}
// A bunch of dummy methods that don't create much
// Your real methods would create more complex JPanels
private JPanel createDecafPanel() {
return createPanel(FinanceFormula.DECAF);
}
private JPanel createCompoundInterestPanel() {
return createPanel(FinanceFormula.COMPOUND_INTEREST);
}
private JPanel createDoublingTimePanel() {
return createPanel(FinanceFormula.DOUBLING_TIME);
}
private JPanel createSimpleInterestPanel() {
return createPanel(FinanceFormula.SIMPLE_INTEREST);
}
private JPanel createPresentValuePanel() {
return createPanel(FinanceFormula.PRESENT_VALUE);
}
private JPanel createNonePanel() {
return createPanel(FinanceFormula.NONE);
}
// temporary method just for demonstration purposes
private JPanel createPanel(FinanceFormula financeFormula) {
JLabel label = new JLabel(financeFormula.getName());
label.setFont(label.getFont().deriveFont(Font.BOLD, 24f));
JPanel panel = new JPanel(new GridBagLayout());
panel.add(label);
panel.setPreferredSize(new Dimension(400, 300));
float split = 0.7f;
float h = (float) (split + Math.random() * (1f - split));
float s = (float) (split + Math.random() * (1f - split));
float b = (float) (split + Math.random() * (1f - split));
Color color = Color.getHSBColor(h, s, b);
panel.setBackground(color);
return panel;
}
private static void createAndShowGui() {
NewFinance2 mainPanel = new NewFinance2();
JFrame frame = new JFrame("Finance");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}