尝试运行我的程序。按添加主题（填写数据）。然后显示。然后添加另一个主题。然后显示。
在“显示”选项卡上，它显示2个主题和1个空主题。
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.border.*;
@SuppressWarnings ({"unchecked" , "rawtypes"})
public class StudentGradeCalc extends JFrame implements ActionListener {
//String setName [];
int x = 0;
int count = 0;
int w = 0;
int [] addSize = {50,10,20,30,40,100};
private JPanel panelInfo = new JPanel(new GridLayout(7,0) );
private JLabel sy = new JLabel ("School Year : ");
private JLabel sem = new JLabel ("Sem/Term: ");
private JLabel Name = new JLabel ("Name : ");
private JLabel Course = new JLabel ("Course : ");
private JLabel Year = new JLabel ("Year : ");
private JLabel college = new JLabel ("College : ");
private JLabel id = new JLabel ("I.D Number : ");
private JTextField syear = new JTextField ("");
private JTextField semnum = new JTextField("");
private JTextField name = new JTextField ("");
private JTextField course = new JTextField ("");
private JTextField year = new JTextField ("");
private JTextField scs = new JTextField("");
private JTextField idnum = new JTextField("");
private JPanel fakebuttons = new JPanel (new GridLayout (4,0,10,10));
private JButton addSubject = new JButton("Add Subject..");
private JButton deleteSubject = new JButton("Delete Subject..");
private JButton editSubject = new JButton("Edit Subject..");
private JButton totalLoad = new JButton("Total Load : ");
private JButton GPA = new JButton ("GPA : ");
private JTextField units_textfield = new JTextField(3);
private JTextField gpa_textfield = new JTextField (7);
private JButton displayInfo = new JButton("Display Data");
private JPanel addPanel = new JPanel(new GridLayout(3,2,20,10));
private JLabel subjectName = new JLabel("Subject: ");
private JTextField subject [] ;
private JLabel gradeLabel = new JLabel("Grade : ");
private JLabel unitsLabel = new JLabel ("Units : ");
private JButton addButton = new JButton ("Add");
String grade [] = {"1.00","1.25","1.50","1.75","2.00","2.25","2.50","2.75","3.00","5.0", "DRP", "INC", "WDRW"};
private JComboBox comboGrade [];
String unit [] = {"1","2","3","4","5","6"};
private JComboBox comboUnit[];
private JButton done = new JButton ("Done");
private JButton d_subj,d_unit,d_grade;
// private JTextField displaySubject = new JTextField();
// private JTextField displayUnit = new JTextField ();
//private JTextField displayGrade = new JTextField();
private JTextField displaySubject[];
private JTextField displayUnit[];
private JTextField displayGrade [];
private JLabel t_units = new JLabel ("Total Load : ");
private JTextField totalUnits = new JTextField ();
private JLabel gpa = new JLabel ("GPA : ");
private JTextField gpaTxt = new JTextField ();
private JLabel err = new JLabel ("No Entry Found");
private JLabel display1 = new JLabel ();
private JLabel display2 = new JLabel ();
private JLabel displayID = new JLabel ();
final String getName [] = new String [10];
final int getUnit [] = new int [10];
final String getGrade [] = new String [10];
public StudentGradeCalc()
{
Border border = BorderFactory.createLineBorder(null);
setLayout(null);
panelInfo.setBounds(5,5,280,150);
//panelInfo.setBorder(border);
panelInfo.add(Name);
panelInfo.add(name);
panelInfo.add(Course);
panelInfo.add(course);
panelInfo.add(Year);
panelInfo.add(year);
panelInfo.add(sy);
panelInfo.add(syear);
panelInfo.add(sem);
panelInfo.add(semnum);
panelInfo.add(college);
panelInfo.add(scs);
panelInfo.add(id);
panelInfo.add(idnum);
add(panelInfo);
fakebuttons.setBounds(5,160,280,160);
fakebuttons.add(addSubject);
fakebuttons.add(deleteSubject);
fakebuttons.add(editSubject);
fakebuttons.add(displayInfo);
add(fakebuttons);
//ADD SUBJECT BUTTON
addSubject.addActionListener(new ActionListener (){
public void actionPerformed (ActionEvent cags){
final JFrame addFrame = new JFrame ();
addFrame.setVisible(true);
addFrame.setSize (300,190);
addFrame.setResizable(false);
addFrame.setLocationRelativeTo(null);
addFrame.setTitle("Add Subject");
//addFrame.setLayout(new GridLayout (3,2,20,10));
addFrame.setLayout(null);
subject = new JTextField [] {
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
new JTextField (),
};
subjectName.setBounds (10,10,120,20);
subject[x].setBounds (75,10,170,20);
addFrame.add(subjectName);
addFrame.add(subject[x]);
gradeLabel.setBounds (10,40,100,20);
addFrame.add(gradeLabel);
comboGrade = new JComboBox [] {
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
new JComboBox (grade),
};
comboGrade[x].setBounds(150,40,95,20);
addFrame.add(comboGrade[x]);
unitsLabel.setBounds (10, 70, 95, 20);
addFrame.add(unitsLabel);
comboUnit = new JComboBox [] {
new JComboBox(unit),
new JComboBox(unit),
new JComboBox(unit),
new JComboBox(unit),
new JComboBox(unit),
new JComboBox(unit),
new JComboBox(unit),
};
comboUnit[x].setBounds(150,70,95,20);
addFrame.add(comboUnit[x]);
addButton.setBounds (120,120,60,30);
addFrame.add(addButton);
w++;
addButton.addActionListener(new ActionListener () {
public void actionPerformed(ActionEvent k){
//JOptionPane.showMessageDialog(null, "Subject "+subject[x].getText()+ " has been added", "Add Subject", JOptionPane.INFORMATION_MESSAGE);
getName [x] = subject[x].getText();
getGrade[x] = String.valueOf((String)comboGrade[x].getSelectedItem());
getUnit [x] = Integer.valueOf((String)comboUnit[x].getSelectedItem());
x++;
addFrame.dispose();
}
});
}
});
//DISPLAY DATA BUTTON
displayInfo.addActionListener(new ActionListener (){
public void actionPerformed(ActionEvent m){
final String name_course_year = "Name : "+name.getText()+ " Course : " +course.getText()+"- "+year.getText()+ " ID : "+idnum.getText() ;
final String ubos = "College : "+scs.getText()+ " SY : "+syear.getText()+ " Term : "+semnum.getText() ;
//String nametanga [] = {name.getText() , };
if (name.getText().equals("")|| course.getText().equals("")||year.getText ().equals("") || idnum.getText().equals("")||syear.getText ().equals("") || scs.getText().equals("")|| semnum.getText().equals(""))
{
JOptionPane.showMessageDialog(null, "Complete the Information!", "ERROR", JOptionPane.WARNING_MESSAGE);
}
else
{
final JFrame display = new JFrame ();
display.setVisible(true);
//display.setSize (400,200);
//display.setSize (400,down+130);
display.setResizable(false);
display.setLocationRelativeTo(null);
display.setTitle("Student Info");
display.setLayout(null);
display1.setBounds (5,5,390,20);
display2.setBounds (5,25,390,20);
display1.setText(name_course_year);
display2.setText(ubos);
display.add(display1);
display.add(display2);
d_subj = new JButton ("Subject");
d_unit = new JButton ("Unit");
d_grade = new JButton ("Grade");
d_subj.setBounds(10,50,180,20);
d_unit.setBounds (200,50,90,20);
d_grade.setBounds(300,50,90,20);
display.add(d_subj);
display.add(d_unit);
display.add(d_grade);
displaySubject = new JTextField [] {
new JTextField(),
new JTextField(),
new JTextField(),
new JTextField(),
new JTextField(),
new JTextField(),
new JTextField(),
};
displayUnit = new JTextField [] {
new JTextField(),new JTextField(),new JTextField(),
new JTextField(),new JTextField(),new JTextField(),
new JTextField(),new JTextField(),
};
displayGrade = new JTextField [] {
new JTextField(),new JTextField(),new JTextField(),
new JTextField(),new JTextField(),new JTextField(),
new JTextField(),new JTextField(),
};
int y = 30;
int down = 80;
int z = 0;
for (int i = 0; i < x; i++)
{
displaySubject[i].setBounds(10,down,180,y);
displayUnit[i].setBounds(200,down,90,y);
displayGrade[i].setBounds(300,down,90,y);
displaySubject[i].setText(getName[i]);
displayUnit[i].setText(""+getUnit[i]);
displayGrade[i].setText(getGrade[i]);
display.add(displaySubject[i]);
display.add(displayUnit[i]);
display.add(displayGrade[i]);
displaySubject[i].setEditable(false);
displayUnit[i].setEditable(false);
displayGrade[i].setEditable(false);
down+=y+10;
//i++;
// z++;
}
display.setSize (400,down+130);
t_units.setBounds (100,down,70,25);
totalUnits.setBounds(180,down,50,25);
gpa.setBounds(260,down,50,25);
gpaTxt.setBounds(310,down,80,25);
display.add(t_units);
display.add(totalUnits);
display.add(gpa);
display.add(gpaTxt);
gpaTxt.setEditable(false);
totalUnits.setEditable(false);
done.setBounds (170,down+50,70,30);
display.add(done);
done.addActionListener (new ActionListener () {
public void actionPerformed (ActionEvent done){
display.dispose();
}
});
}
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setSize (300,355);
setResizable(false);
setLocationRelativeTo(null);
setTitle("Student Grade Calculator");
}
public void actionPerformed (ActionEvent vahn)
{
System.exit(1);
}
public static void main(String[] args) {
new StudentGradeCalc();
}
}
我不知道在哪里可以找到我的程序出错的原因。
答案 0 :(得分：0)
我发现你的问题就在这里 addButton.addActionListener（）。您总是向按钮实例添加一个新的ActionListener，因此，每次按 addSubject 按钮时，您还会向 addButton 添加一个新的侦听器。在将来不要这样做，在组件构造方法中将监听器添加到组件。