此代码中的清除和退出按钮在点击时不会执行任何操作。我做错了什么？
public class VehicleMenu extends JFrame implements ActionListener{
private static final long serialVersionUID = 1L;
private static final String FILE_NAME = "BB_Automobil's_Inventory Record.txt";
private JTextField jtfCode, jtfBrand, jtfEngineNumber, jtfEngineType, jtfMaxHorsepower, jtfRangePerFillUp, jtfPrice, jtfResult;
private JButton calculateButton, saveButton, clearButton, exitButton;
private JComboBox typeCombo;
private JPanel comboPanel, buttonPanel;
private String[] type = {"Sports Car","Hybrid Car"};
private Container windowContainer;
private JMenuItem jmiSearch, jmiUpdate, jmiDelete, jmiClose;
public VehicleMenu (int w, int h){
//Set window size and title
this.setSize(w, h);
this.setTitle("BB Automobile's Inventory Record");
//create menu bar
JMenuBar jmb = new JMenuBar();
//add menu "Exit" to menu bar
JMenu optionsMenu = new JMenu("Options");
optionsMenu.setMnemonic('O');
jmb.add(optionsMenu);
//add menu "Exit" to menu bar
JMenu exitMenu = new JMenu("Exit");
exitMenu.setMnemonic('E');
jmb.add(exitMenu);
//add menu items
optionsMenu.add(jmiSearch=new JMenuItem("Search",'S'));
optionsMenu.add(jmiUpdate=new JMenuItem("Update",'U'));
optionsMenu.add(jmiDelete = new JMenuItem("Delete",'D'));
exitMenu.add(jmiClose = new JMenuItem("Close",'C'));
//Create textfields
jtfCode = new JTextField(10);
jtfBrand = new JTextField(10);
jtfEngineType = new JTextField(10);
jtfPrice = new JTextField(10);
//Create buttons
calculateButton = new JButton("Calculate");
saveButton = new JButton("Save");
clearButton = new JButton("Clear");
exitButton = new JButton("Exit");
//exitButton.setToolTipText("Out of Program");
//Attach listeners to the buttons
calculateButton.addActionListener(this);
saveButton.addActionListener(this);
clearButton.addActionListener(this);
exitButton.addActionListener(this);
//Create combobox
typeCombo = new JComboBox(type);
//Attach listeners to the comboboxes
typeCombo.addActionListener(this);
//attach ActionListener to menu item
jmiClose.addActionListener(this);
//Create panels
comboPanel=new JPanel();
buttonPanel = new JPanel();
//Get contentPane and set its layout
windowContainer = getContentPane();
//add menu bar to the frame
windowContainer.add(jmb,BorderLayout.NORTH);
//to create topPanel with label and text field
JPanel topPanel = new JPanel();
topPanel.setLayout(new GridLayout(9,2,10,5));
//Create combobox
topPanel.add(new JLabel("Type:"));
topPanel.add(typeCombo = new JComboBox(type));
topPanel.add(new JLabel("Code:"));
topPanel.add(jtfCode = new JTextField(3));
topPanel.add(new JLabel("Brand:"));
topPanel.add(jtfBrand = new JTextField(3));
topPanel.add(new JLabel("Engine Number:"));
topPanel.add(jtfEngineNumber = new JTextField(3));
topPanel.add(new JLabel("Engine Type:"));
topPanel.add(jtfEngineType = new JTextField(3));
topPanel.add(new JLabel("Maximum horse power(Sports Car):"));
topPanel.add(jtfMaxHorsepower = new JTextField(3));
topPanel.add(new JLabel("Range per fill up(Hybrid Car):"));
topPanel.add(jtfRangePerFillUp = new JTextField(3));
topPanel.add(new JLabel("Price: RM"));
topPanel.add(jtfPrice = new JTextField(3));
topPanel.add(new JLabel("Discount: RM"));
topPanel.add(jtfResult = new JTextField(3));
jtfResult.setEditable(false);
//to create bottom panel with buttons
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new FlowLayout());
bottomPanel.add(calculateButton = new JButton("Calculate"));
bottomPanel.add(saveButton = new JButton("Save"));
bottomPanel.add(clearButton = new JButton("Clear"));
bottomPanel.add(exitButton = new JButton("Exit"));
//ADD topPanel, middlePanel and bottomPanel to the frame
windowContainer.add(topPanel,BorderLayout.CENTER);
windowContainer.add(bottomPanel,BorderLayout.SOUTH);
//Add buttons to buttonPanel
buttonPanel.add(calculateButton);
buttonPanel.add(saveButton);
buttonPanel.add(clearButton);
buttonPanel.add(exitButton);
//Add panels to content panel
this.add(buttonPanel, BorderLayout.SOUTH);
}//end constructor
public void actionPerformed(ActionEvent ae) {
typeCombo.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent arg0) {
if (typeCombo.getSelectedItem().toString()
.equalsIgnoreCase("Sports Car")) {
jtfMaxHorsepower.setVisible(true);
jtfRangePerFillUp.setVisible(false);
} else {
jtfMaxHorsepower.setVisible(false);
jtfRangePerFillUp.setVisible(true);
}
}
});
//declare Clicked to make JButton can move
//JButton Clicked = (JButton) ae.getSource();
//assign value from JTextField to new variable to link all the data members to GUI
String typeM = typeCombo.getName();
String codeM = jtfCode.getText();
String brandM = jtfBrand.getText();
String engineNumberM = jtfEngineNumber.getText();
String engineTypeM = jtfEngineType.getText();
//Invoke the composition into GUI with data members
Engine eng = new Engine(engineNumberM,engineTypeM);
double priceM = 0;
//Invoke the superclass into GUI with their data members
Car car = new Car(eng,priceM,codeM,brandM);
double maxHorsepowerM = 0;
//Invoke the subclasses into GUI together with their data members
SportsCar sportsCar = new SportsCar(maxHorsepowerM,eng,priceM);
double rangePerFillUpM = 0;
HybridCar hybridCar = new HybridCar(rangePerFillUpM,eng,priceM);
if(ae.getSource() == saveButton) {
try
{
if(car.getEngine().equals("") || car.getPrice()==0.0
|| eng.getEngineNumber().equals("")|| eng.getEngineType().equals("")
|| (sportsCar.getMaxHorsepower()==0.0 || hybridCar.getRangePerFillUp()==0.0))
{
//exception for empty field
JOptionPane.showMessageDialog(null,"Inserting data is incomplete. Please fully insert the data",
"Wrong input", JOptionPane.WARNING_MESSAGE);
}
//SAVE the data into text file
else
{
String typeN = typeM.trim();
String engineNumberN = eng.getEngineNumber().trim();
String engineTypeN = eng.getEngineType().trim();
double maxHorsepowerN = sportsCar.getMaxHorsepower();
double rangePerFillUpN = hybridCar.getRangePerFillUp();
double priceN = car.getPrice();
//declaring object to write data to file
CustomFileWriter fw = new CustomFileWriter();
//either fill maxHorsepower(SportsCar) or rangePerFillUp(HybridCar)
if(maxHorsepowerM != 0.0)
{
String input = typeN +", "+ codeM +", "+ brandM +", "+ engineNumberN +", "
+ engineTypeN +", "+ maxHorsepowerN +", "+ priceN;
fw.writeToFile(FILE_NAME, sportsCar, true);
}
else if(rangePerFillUpM != 0.0)
{
String input = typeN +", "+ codeM +", "+ brandM +", "+ engineNumberN +", "
+ engineTypeN +", "+ rangePerFillUpN +", "+ priceN;
fw.writeToFile(FILE_NAME, hybridCar, true);
}
}
} //end else if AND try for SAVE
catch (Exception e1)
{
e1.printStackTrace();
}
}// end if SAVE
{
//to reset the input in the textfield
if(ae.getSource() == clearButton)
{
jtfCode.setText("");
jtfBrand.setText("");
jtfEngineNumber.setText("");
jtfEngineType.setText("");
jtfMaxHorsepower.setText("");
jtfRangePerFillUp.setText("");
jtfPrice.setText("");
}
else if(ae.getSource() == exitButton)
{ System.exit(0); }
else if(ae.getSource()== jmiClose)
{ System.exit(0);}
}
{
//DELETE
if(ae.getSource() == jmiDelete)
{
//open file to DELETE saved data
PrintWriter pw;
try {
pw = new PrintWriter(FILE_NAME);
pw.print("");
pw.close();
} catch (FileNotFoundException e1) {
e1.printStackTrace();
}
JOptionPane.showMessageDialog(null,
"Successfully delete content from BB's_Automobile_Inventory_Record.txt",
"Delete from file", JOptionPane.INFORMATION_MESSAGE);
}
}
按钮已创建，动作侦听器在那里，是actionPerformed吗？请帮助我，这非常令人困惑。
答案 0 :(得分：0)
你在这个区块中声明并创建按钮：
//Create buttons
calculateButton = new JButton("Calculate");
saveButton = new JButton("Save");
clearButton = new JButton("Clear");
exitButton = new JButton("Exit");
然后你将addin these按钮添加到动作监听器中，但是在这个块中你创建了新的按钮，这些是可见的按钮。
//to create bottom panel with buttons
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new FlowLayout());
bottomPanel.add(calculateButton = new JButton("Calculate"));
bottomPanel.add(saveButton = new JButton("Save"));
bottomPanel.add(clearButton = new JButton("Clear"));
bottomPanel.add(exitButton = new JButton("Exit"));
只需将其改为此即可。
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new FlowLayout());
bottomPanel.add(calculateButton );
bottomPanel.add(saveButton )
bottomPanel.add(clearButton );
bottomPanel.add(exitButton);
但是为了使你的代码更具可读性，你应该使用匿名监听器（有人已经在评论中提到过）。 所以不要这样：
calculateButton.addActionListener(this);
对每个按钮使用类似的东西：
calculateButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
//Your code
}
});
希望这会有所帮助（：