我制作了一个计算器并增加了它的功能和简单性我制作了三个框架，支持简单，科学和转换计算器
计算器工作完美，直到我使用它一次，但是当我将计算器类型从简单变为科学和科学再到转换再转换为简单的计算器时，程序根本不做任何事情，jbutton甚至不执行任何操作actionPerformed被调用我通过将println语句放在方法actionPerformed中来检查。
我在构造函数中实例化了我的三个框架，我为计算器类型制作了三个方法，以实例化并向JPanels添加按钮和其他内容，并将面板添加到JFrame
//Constructor
public Calculator()
{
//instantiating buttons
buttons = new JButton[15];
optionButtons = new JButton[5];
scientificOptionButtons = new JButton[20];
constantButtons = new JButton[5];
//instantiating calculatorFrames
simpleCalculatorFrame = new JFrame("Calculator");
scientificCalculatorFrame = new JFrame("Scientific Calculator");
convertCalculatorFrame = new JFrame("Conversion Calculator");
} // end of the constructor
当我从我的JMenuItems中选择计算器类型时，我处理活动框架并调用其他计算类型方法来创建和添加面板并设置框架，如
//if statements inside method actionPerformed to check which type of calculator should run
if(event.getSource() == scientificMenuItem)
{
if(simpleCalculatorFrame.isActive())
{
simpleCalculatorFrame.dispose();
scientificCalculatorBuilder();
}
else if(convertCalculatorFrame.isActive())
{
convertCalculatorFrame.dispose();
scientificCalculatorBuilder();
}
}
else if(event.getSource() == simpleMenuItem)
{
if(scientificCalculatorFrame.isActive())
{
scientificCalculatorFrame.dispose();
simpleCalculatorBuilder();
}
else if(convertCalculatorFrame.isActive())
{
convertCalculatorFrame.dispose();
simpleCalculatorBuilder();
}
}
else if(event.getSource() == convertMenuItem)
{
if(simpleCalculatorFrame.isActive())
{
simpleCalculatorFrame.dispose();
convertCalculatorBuilder();
}
else if(scientificCalculatorFrame.isActive())
{
scientificCalculatorFrame.dispose();
convertCalculatorBuilder();
}
}
else if(event.getSource() == exitMenuItem)
{
System.exit(0);
}
一切看起来都很好，只是没有问题在哪里
这是我的方法代码，用于实例化组件
public void simpleCalculatorBuilder()
{
//instantiating menuBar , fileMenu and menuItems and adding functionality
menuBar = new JMenuBar();
fileMenu = new JMenu("File");
scientificMenuItem = new JMenuItem("Scientific Calculator");
convertMenuItem = new JMenuItem("Conversion Calculator");
convertMenuItem.addActionListener(handler);
scientificMenuItem.addActionListener(handler);
exitMenuItem = new JMenuItem("Exit");
exitMenuItem.addActionListener(handler);
menuBar.add(fileMenu);
fileMenu.add(scientificMenuItem);
fileMenu.add(convertMenuItem);
fileMenu.add(exitMenuItem);
//instantiating and adding textField appearing at the top of calculator to show ongoing processes and results
myField = new JTextField();
myField.setPreferredSize(new Dimension(this.getWidth() , 40));
myField.setEditable(false);
simpleCalculatorFrame.add(myField , BorderLayout.NORTH);
//instantiating panels to hold buttons
buttonsPanel = new JPanel(new GridLayout(5 , 3 , 3 , 6));
optionButtonsPanel = new JPanel(new GridLayout(5, 1 , 3 , 3));
//loop to add buttons to panel , adding eventListeners to buttons , setting background color of buttons
for(int i = 0 ; i<buttons.length ; i++)
{
buttons[i] = new JButton(buttonTitles[i]);
buttons[i].setBackground(Color.BLACK);
buttons[i].setForeground(Color.WHITE);
buttons[i].addActionListener(handler);
buttons[i].addMouseListener(handler);
buttonsPanel.add(buttons[i]);
if(i<5)
{
optionButtons[i] = new JButton(optionButtonTitles[i]);
optionButtons[i].setBackground(Color.BLACK);
optionButtons[i].setForeground(Color.WHITE);
optionButtons[i].addActionListener(handler);
optionButtons[i].addMouseListener(handler);
optionButtonsPanel.add(optionButtons[i]);
}
}
//setting background color of panels
buttonsPanel.setBackground(Color.DARK_GRAY);
optionButtonsPanel.setBackground(Color.DARK_GRAY);
//adding items and panels to the frame and setting the simpleCalculatorFrame
simpleCalculatorFrame.setJMenuBar(menuBar);
simpleCalculatorFrame.add(buttonsPanel , BorderLayout.CENTER);
simpleCalculatorFrame.add(optionButtonsPanel , BorderLayout.EAST);
simpleCalculatorFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
simpleCalculatorFrame.setSize(240 , 270);
simpleCalculatorFrame.setLocationRelativeTo(null);
simpleCalculatorFrame.setVisible(true);
simpleCalculatorFrame.setResizable(false);
} // end of simple calculator builder
public void scientificCalculatorBuilder()
{
//instantiating menuBar , fileMenu and menuItems and adding functionality
menuBar = new JMenuBar();
fileMenu = new JMenu("File");
simpleMenuItem = new JMenuItem("Simple Calculator");
simpleMenuItem.addActionListener(handler);
convertMenuItem = new JMenuItem("Conversion Calculator");
convertMenuItem.addActionListener(handler);
exitMenuItem = new JMenuItem("Exit");
exitMenuItem.addActionListener(handler);
menuBar.add(fileMenu);
fileMenu.add(simpleMenuItem);
fileMenu.add(convertMenuItem);
fileMenu.add(exitMenuItem);
//instantiating and adding textField appearing at the top of calculator to show ongoing processes and results
myField = new JTextField();
myField.setPreferredSize(new Dimension(this.getWidth() , 40));
myField.setEditable(false);
scientificCalculatorFrame.add(myField , BorderLayout.NORTH);
//instantiating panels to hold buttons
buttonsPanel = new JPanel(new GridLayout(5 , 3 , 3 , 6));
optionButtonsPanel = new JPanel(new GridLayout(5, 1 , 3 , 3));
scientificOptionButtonsPanel = new JPanel(new GridLayout(5 , 4 , 3 , 3));
constantButtonsPanel = new JPanel(new GridLayout(5, 1 , 3 , 3));
scientificPanelManager = new JPanel(new GridLayout(1 , 2));
//loop to add buttons to panel , adding eventListeners to buttons , setting background color of buttons
for(int i = 0 ; i<scientificOptionButtons.length ; i++)
{
if(i<5)
{
optionButtons[i] = new JButton(optionButtonTitles[i]);
optionButtons[i].setBackground(Color.BLACK);
optionButtons[i].setForeground(Color.WHITE);
optionButtons[i].addActionListener(handler);
optionButtons[i].addMouseListener(handler);
optionButtonsPanel.add(optionButtons[i]);
constantButtons[i] = new JButton(constantButtonTitles[i]);
constantButtons[i].setBackground(Color.BLACK);
constantButtons[i].setForeground(Color.WHITE);
constantButtons[i].addActionListener(handler);
constantButtons[i].addMouseListener(handler);
constantButtonsPanel.add(constantButtons[i]);
}
if(i<15)
{
buttons[i] = new JButton(buttonTitles[i]);
buttons[i].setBackground(Color.BLACK);
buttons[i].setForeground(Color.WHITE);
buttons[i].addActionListener(handler);
buttons[i].addMouseListener(handler);
buttonsPanel.add(buttons[i]);
}
scientificOptionButtons[i] = new JButton(scientificOptionButtonTitles[i]);
scientificOptionButtons[i].setBackground(Color.BLACK);
scientificOptionButtons[i].setForeground(Color.WHITE);
scientificOptionButtons[i].addActionListener(handler);
scientificOptionButtons[i].addMouseListener(handler);
scientificOptionButtonsPanel.add(scientificOptionButtons[i]);
}// end of for loop
//setting background color of panels
buttonsPanel.setBackground(Color.DARK_GRAY);
optionButtonsPanel.setBackground(Color.DARK_GRAY);
scientificOptionButtonsPanel.setBackground(Color.DARK_GRAY);
constantButtonsPanel.setBackground(Color.DARK_GRAY);
scientificPanelManager.add(scientificOptionButtonsPanel);
scientificPanelManager.add(buttonsPanel);
scientificCalculatorFrame.setJMenuBar(menuBar);
scientificCalculatorFrame.add(constantButtonsPanel , BorderLayout.WEST);
scientificCalculatorFrame.add(optionButtonsPanel , BorderLayout.EAST);
scientificCalculatorFrame.add(scientificPanelManager , BorderLayout.CENTER);
scientificCalculatorFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
scientificCalculatorFrame.setSize(580 , 300);
scientificCalculatorFrame.setLocationRelativeTo(null);
scientificCalculatorFrame.setVisible(true);
scientificCalculatorFrame.setResizable(false);
} // end of scientificCalculatorBuilder
//method which starts convertCalculatorFrame and initializes frame needs
public void convertCalculatorBuilder()
{
convertCalculatorTopPanel = new JPanel(new GridLayout(2 , 1 , 0 , 4));
convertCalculatorCenterPanel = new JPanel(new GridLayout(2 , 2 , 5 , 3));
convertCalculatorEastPanel = new JPanel(new GridLayout(2 , 1 ,1 , 3));
convertCalculatorSouthPanel = new JPanel(new GridLayout(1 , 2 , 5 , 2));
//instantiating menuBar , fileMenu and menuItems and adding functionality
menuBar = new JMenuBar();
fileMenu = new JMenu("File");
simpleMenuItem = new JMenuItem("Simple Calculator");
simpleMenuItem.addActionListener(handler);
scientificMenuItem = new JMenuItem("Scientific Calculator");
scientificMenuItem.addActionListener(handler);
exitMenuItem = new JMenuItem("Exit");
exitMenuItem.addActionListener(handler);
menuBar.add(fileMenu);
fileMenu.add(simpleMenuItem);
fileMenu.add(scientificMenuItem);
fileMenu.add(exitMenuItem);
typeConvertCalculatorComboBox = new JComboBox<String>();
typeConvertCalculatorComboBox.setBackground(Color.BLACK);
typeConvertCalculatorComboBox.setForeground(Color.WHITE);
typeConvertCalculatorComboBox.setMaximumRowCount(3);
typeConvertCalculatorComboBox.addItem("Choose type of conversion");
typeConvertCalculatorComboBox.addItem("Distance Conversion");
typeConvertCalculatorComboBox.addItem("Memory Conversion");
typeConvertCalculatorComboBox.addItem("Temperature Conversion");
typeConvertCalculatorComboBox.addItem("Mass Conversion");
typeConvertCalculatorComboBox.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
if(typeConvertCalculatorComboBox.getSelectedItem() == "Distance Conversion")
{
fromConvertCalculatorComboBox.setEnabled(true);
toConvertCalculatorComboBox.setEnabled(true);
fromConvertCalculatorComboBox.removeAllItems();
fromConvertCalculatorComboBox.setMaximumRowCount(3);
fromConvertCalculatorComboBox.addItem("Centimeter(s)");
fromConvertCalculatorComboBox.addItem("Meter(s)");
fromConvertCalculatorComboBox.addItem("Kilometer(s)");
fromConvertCalculatorComboBox.addItem("Mile(s)");
toConvertCalculatorComboBox.removeAllItems();
toConvertCalculatorComboBox.setMaximumRowCount(2);
toConvertCalculatorComboBox.addItem("Centimeter(s)");
toConvertCalculatorComboBox.addItem("Meter(s)");
toConvertCalculatorComboBox.addItem("Kilometer(s)");
toConvertCalculatorComboBox.addItem("Mile(s)");
}
else if(typeConvertCalculatorComboBox.getSelectedItem() == "Memory Conversion")
{
fromConvertCalculatorComboBox.setEnabled(true);
toConvertCalculatorComboBox.setEnabled(true);
fromConvertCalculatorComboBox.removeAllItems();
fromConvertCalculatorComboBox.setMaximumRowCount(3);
fromConvertCalculatorComboBox.addItem("Kilobyte(s)");
fromConvertCalculatorComboBox.addItem("Megabyte(s)");
fromConvertCalculatorComboBox.addItem("Gigabyte(s)");
fromConvertCalculatorComboBox.addItem("Terabyte(s)");
toConvertCalculatorComboBox.removeAllItems();
toConvertCalculatorComboBox.setMaximumRowCount(2);
toConvertCalculatorComboBox.addItem("Kilobyte(s)");
toConvertCalculatorComboBox.addItem("Megabyte(s)");
toConvertCalculatorComboBox.addItem("Gigabyte(s)");
toConvertCalculatorComboBox.addItem("Terabyte(s)");
}
else if(typeConvertCalculatorComboBox.getSelectedItem() == "Temperature Conversion")
{
fromConvertCalculatorComboBox.setEnabled(true);
toConvertCalculatorComboBox.setEnabled(true);
fromConvertCalculatorComboBox.removeAllItems();
fromConvertCalculatorComboBox.addItem("Centigrade");
fromConvertCalculatorComboBox.addItem("Fahrenheit");
fromConvertCalculatorComboBox.addItem("Kelvin");
toConvertCalculatorComboBox.removeAllItems();
toConvertCalculatorComboBox.setMaximumRowCount(2);
toConvertCalculatorComboBox.addItem("Centigrade");
toConvertCalculatorComboBox.addItem("Fahrenheit");
toConvertCalculatorComboBox.addItem("Kelvin");
}
else if(typeConvertCalculatorComboBox.getSelectedItem() == "Mass Conversion")
{
fromConvertCalculatorComboBox.setEnabled(true);
toConvertCalculatorComboBox.setEnabled(true);
fromConvertCalculatorComboBox.removeAllItems();
fromConvertCalculatorComboBox.setMaximumRowCount(3);
fromConvertCalculatorComboBox.addItem("Milligram(s)");
fromConvertCalculatorComboBox.addItem("Pound(s) (lbs)");
fromConvertCalculatorComboBox.addItem("Kilogram(s)");
toConvertCalculatorComboBox.removeAllItems();
toConvertCalculatorComboBox.setMaximumRowCount(2);
toConvertCalculatorComboBox.addItem("Milligram(s)");
toConvertCalculatorComboBox.addItem("Pound(s) (lbs)");
toConvertCalculatorComboBox.addItem("Kilogram(s)");
}
}
}
);
fromConvertCalculatorComboBox = new JComboBox<String>();
fromConvertCalculatorComboBox.setMaximumRowCount(3);
fromConvertCalculatorComboBox.setBackground(Color.BLACK);
fromConvertCalculatorComboBox.setForeground(Color.WHITE);
fromConvertCalculatorComboBox.setEnabled(false);
toConvertCalculatorComboBox = new JComboBox<String>();
toConvertCalculatorComboBox.setMaximumRowCount(2);
toConvertCalculatorComboBox.setBackground(Color.BLACK);
toConvertCalculatorComboBox.setForeground(Color.WHITE);
toConvertCalculatorComboBox.setEnabled(false);
topConvertCalculatorLabel = new JLabel("What type of conversion you want ?");
topConvertCalculatorLabel.setForeground(Color.WHITE);
fromConvertCalculatorLabel = new JLabel("From");
fromConvertCalculatorLabel.setForeground(Color.WHITE);
toConvertCalculatorLabel = new JLabel("To");
toConvertCalculatorLabel.setForeground(Color.WHITE);
fromConvertCalculatorField = new JTextField();
fromConvertCalculatorField.setPreferredSize(new Dimension(120 , 2));
fromConvertCalculatorField.addActionListener(convertHandler);
ansConvertCalculatorField = new JTextField();
ansConvertCalculatorField.setEditable(false);
convertButton = new JButton("Convert");
convertButton.setBackground(Color.BLACK);
convertButton.setForeground(Color.WHITE);
convertButton.addMouseListener(handler);
convertButton.addActionListener(convertHandler);
convertCalculatorFrame.setJMenuBar(menuBar);
//adding components to panel and adding panels to frame
{
convertCalculatorTopPanel.add(topConvertCalculatorLabel);
convertCalculatorTopPanel.add(typeConvertCalculatorComboBox);
convertCalculatorTopPanel.setBackground(Color.DARK_GRAY);
convertCalculatorFrame.add(convertCalculatorTopPanel , BorderLayout.NORTH);
convertCalculatorCenterPanel.add(fromConvertCalculatorLabel);
convertCalculatorCenterPanel.add(fromConvertCalculatorComboBox);
convertCalculatorCenterPanel.add(toConvertCalculatorLabel);
convertCalculatorCenterPanel.add(toConvertCalculatorComboBox);
convertCalculatorCenterPanel.setBackground(Color.DARK_GRAY);
convertCalculatorFrame.add(convertCalculatorCenterPanel , BorderLayout.CENTER);
convertCalculatorEastPanel.add(fromConvertCalculatorField);
convertCalculatorEastPanel.setBackground(Color.DARK_GRAY);
convertCalculatorFrame.add(convertCalculatorEastPanel , BorderLayout.EAST);
convertCalculatorSouthPanel.add(convertButton);
convertCalculatorSouthPanel.add(ansConvertCalculatorField);
convertCalculatorSouthPanel.setBackground(Color.DARK_GRAY);
convertCalculatorFrame.add(convertCalculatorSouthPanel , BorderLayout.SOUTH);
convertCalculatorFrame.getContentPane().validate();
convertCalculatorFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
convertCalculatorFrame.setSize(390 , 200);
convertCalculatorFrame.setLocationRelativeTo(null);
convertCalculatorFrame.setVisible(true);
convertCalculatorFrame.setResizable(false);
}
}//end of convertCalculatorBuilder
我在编程方面没有太多经验，希望人们不介意帮助
这是一个MCVE
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Test {
public static void main(String[] args) {
Practice application = new Practice();
application.forFrame1();
}
}
class Practice extends JPanel
{
Handler handler = new Handler();
private JButton[] buttons;
private JButton[] moreButtons;
private JMenuBar menuBar;
private JMenu myMenu;
private JMenuItem firstItem;
private JMenuItem secondItem;
private JFrame frame1;
private JFrame frame2;
private JPanel panel1;
private JPanel panel2;
public Practice()
{
buttons = new JButton[3];
moreButtons = new JButton[5];
frame1 = new JFrame();
frame2 = new JFrame();
}
public void forFrame1()
{
menuBar = new JMenuBar();
myMenu = new JMenu("menu");
secondItem = new JMenuItem("goto 2nd frame");
secondItem.addActionListener(handler);
menuBar.add(myMenu);
myMenu.add(secondItem);
frame1.setJMenuBar(menuBar);
panel1 = new JPanel(new GridLayout(3 , 1));
for(int i = 0 ; i<buttons.length ; i++)
{
buttons[i] = new JButton(""+ i);
buttons[i].addActionListener(handler);
panel1.add(buttons[i]);
}
frame1.add(panel1);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setSize(200 , 200);
frame1.setVisible(true);
}
public void forFrame2()
{
menuBar = new JMenuBar();
myMenu = new JMenu("menu");
firstItem = new JMenuItem("goto 1st frame");
firstItem.addActionListener(handler);
menuBar.add(myMenu);
myMenu.add(firstItem);
frame2.setJMenuBar(menuBar);
panel2 = new JPanel(new GridLayout(1 , 5));
for(int i = 0 ; i<moreButtons.length ; i++)
{
moreButtons[i] = new JButton(""+ i);
moreButtons[i].addActionListener(handler);
panel2.add(moreButtons[i]);
}
frame2.add(panel2);
frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame2.setSize(200 , 200);
frame2.setVisible(true);
}
private class Handler implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
if(event.getSource() == firstItem)
{
frame2.dispose();
forFrame1();
}
else if(event.getSource() == secondItem)
{
frame1.dispose();
forFrame2();
}
for(int i = 0 ; i< moreButtons.length ; i++)
{
if(i<buttons.length)
{
if(event.getSource() == buttons[i])
JOptionPane.showMessageDialog(null, "frame1 component working");
}
if(event.getSource() == moreButtons[i])
JOptionPane.showMessageDialog(null, "frame2 components working");
}
}
}
}
通过选择menuItem
来更改框架后尝试使用组件答案 0 :(得分：2)
如果没有mcve，我就不会通过所有代码，但是您的症状告诉我整体问题和解决方案：您重新构建已经创建的JFrame，重新 - 使用组件进行填充，无需移除旧组件，无需取消旧听众，组件就无法工作。这表明在重建已经构建的GUI的过程中某些东西正在破坏你的功能，如果是这样，解决方案就是不这样做。如果您绝对需要交换JFrame（顺便说一下，从用户的角度来看，这是一个非常恼人的GUI设计），那么只需创建一次GUI对象，但如果需要，可以多次显示它们。换句话说，只需在构造函数中调用构建器方法一次，并在按钮的ActionListener中调用构建器方法，而不是仅调用.setVisible(true)和.setVisible(false)
导致错误的错误是您将组件添加到已填充的JFrame并且未打包它，因此显示并按下旧按钮，但它们的引用不匹配新按钮的那个。要自己查看此内容，请为每个forFrame1()和forFrame2()方法添加一行：
frame1.getContentPane().removeAll(); // ****** add this *****
frame1.add(panel1);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setSize(200, 200);
frame1.setVisible(true);
通过删除所有旧组件，您将显示并运行所有新组件，并且您的代码将起作用。
话虽如此，我仍然觉得你的设计有几个方面：
答案 1 :(得分：0)
我认为你应该使用JFrame.setVisible（false）而不是JFrame.dispose（）