JComboBox problems

Hello all,

I'm having some problems with my program regarding JComboBoxes.
My JComboBox won't display an array of StudentClass objects. :confused:

Also, how would I be able to update the JComboBox which contains the array which would hold the StudentClass objects that that user input?

Once I can get that to work, I need to figure out how to "delete" the selected item from the JComboBox.

How would I go about doing this?

Also, where the GUI says "This student's current average is: 0.0%."
I've been trying to figure out as to why it doesn't update when "Add this student!" is pressed.

All help is appreciated.
Thanks in advance!
-Ecliptical

Here are the 3 classes needed to run the program.

Code:

---

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JTabbedPane;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.JSeparator;
import javax.swing.JComboBox;
import java.awt.event.KeyEvent;
import java.lang.String;
import java.util.ArrayList;

public class BHSSDatabasePanelTABBED extends JPanel implements ActionListener
{
  private JLabel mainDisplay, line1, studNameLabel, osisLabel, cutsLabel, examGradeLabel1, examGradeLabel2, examGradeLabel3, examGradeLabel4, finalExamLabel, homeworkLabel, homeworkCLabel, studentListLabel, teacherNameLabel, teacherListLabel, classNameLabel,
    classListLabel, finalGrade, studentOsisLabel, studentAddressLabel, teacherClassLabel, teacherDeptLabel, teacherSalaryLabel;
  private JTabbedPane tabbedPanel;
  private JPanel panel1, panel2, panel3, panel4;
  public static JPanel primary;
  // private JComponent panel1, panel2, panel3, panel4; //<<<---- What exactly does this do?
  private JTextField studentNameInput, studentAddressInput, osisInput, cutsInput, homeworkInput, homeworkCInput, examGrade1Input, examGrade2Input, examGrade3Input, examGrade4Input, finalExamInput,
    projectGrade1Input, projectGrade2Input, projectGrade3Input, teacherNameInput, classNameInput, teacherClassInput, teacherSalaryInput, teacherDeptInput;
  private JComboBox studentNameList, studentNameList2, teacherNameList, classNameList;
  private JButton button1, button2, button3, button4, button5, button6, button7;
  private ArrayList <StudentClass> students;
  private StudentClass [] students1;
  private JSeparator separator1, separator2, separator3, separator4;
  private double average;
  private int index;
 
  public BHSSDatabasePanelTABBED()
  {
    students = new ArrayList<StudentClass>();
    average = 0;
    index = 1;
    students1 = new StudentClass[150];
   
   
    panel1 = new JPanel();
   
    //tabbedPanel.addTab("Add/Remove A Person", panel2);
    studNameLabel = new JLabel("Input the student's name which you wish to add.");
    studentNameInput = new JTextField(20);
    studentAddressLabel = new JLabel("Students Address");
    studentAddressInput = new JTextField(15);
    osisLabel = new JLabel("Input the student's OSIS.");
    osisInput = new JTextField(9);
    cutsLabel = new JLabel("Input the number of cuts");
    cutsInput = new JTextField(3);
    examGradeLabel1 = new JLabel("Exam 1 Grade");
    examGrade1Input = new JTextField(3);
    examGradeLabel2 = new JLabel("Exam 2 Grade");
    examGrade2Input = new JTextField(3);
    examGradeLabel3 = new JLabel("Exam 3 Grade");
    examGrade3Input = new JTextField(3);
    examGradeLabel4 = new JLabel("Exam 4 Grade");
    examGrade4Input = new JTextField(3);
    finalExamLabel = new JLabel("Final Exam Grade");
    finalExamInput = new JTextField(3);
    homeworkLabel = new JLabel("Number of HW Completed");
    homeworkInput = new JTextField(3);
    homeworkCLabel = new JLabel("Total Number of HW Assignments");
    homeworkCInput = new JTextField (3);
    button1 = new JButton("Add A Student!");
    button1.addActionListener(this);
    finalGrade = new JLabel("This student's final grade is: " + average + "%");
    studentListLabel = new JLabel("Select the student who you wish to delete.");
    studentNameList = new JComboBox(students1);
    mainDisplay = new JLabel("Welcome to the BHSS Database");
//<--- //*************How do display the array. Code isn't working. Tried looking at API***********
    button2 = new JButton("Drop this student!");
    button2.addActionListener(this);
   
    panel1.add(mainDisplay);
    panel1.add(studNameLabel);
    panel1.add(studentNameInput);
    panel1.add(osisLabel);
    panel1.add(osisInput);
    panel1.add(cutsLabel);
    panel1.add(cutsInput);
    panel1.add(studentAddressLabel);
    panel1.add(studentAddressInput);
    panel1.add(examGradeLabel1);
    panel1.add(examGrade1Input);
    panel1.add(examGradeLabel2);
    panel1.add(examGrade2Input);
    panel1.add(examGradeLabel3);
    panel1.add(examGrade3Input);
    panel1.add(examGradeLabel4);
    panel1.add(examGrade4Input);
    panel1.add(finalExamLabel);
    panel1.add(finalExamInput);
    panel1.add(homeworkLabel);
    panel1.add(homeworkInput);
    panel1.add(homeworkCLabel);
    panel1.add(homeworkCInput);
    panel1.add(button1); //Add this student!
    panel1.add(finalGrade);
    panel1.add(studentListLabel);
    panel1.add(studentNameList);
    panel1.add(button2); //Delete this student!
   
    line1 = new JLabel("Please choose the tab which best suits your needs");
   
    tabbedPanel = new JTabbedPane();
    add(tabbedPanel);
    tabbedPanel.addTab("Add/Remove Student", panel1);
   
    primary = new JPanel();
    primary.setBackground (Color.white);
    primary.setPreferredSize (new Dimension(500, 475));
    primary.setLayout( new BorderLayout() );
    primary.add( tabbedPanel, BorderLayout.CENTER );

    tabbedPanel.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
    setPreferredSize(new Dimension(345, 550));
  }
 
  public void actionPerformed(ActionEvent e)
  {
    if(e.getSource() == button1)
    {
      StudentClass student = new StudentClass();
      String a, d;
      int b, c, f;
      a = studentNameInput.getText();
      b = Integer.parseInt(osisInput.getText());
      c = Integer.parseInt(cutsInput.getText());
      d = studentAddressInput.getText();
      f = Integer.parseInt(osisInput.getText());
      student.setName(a);
      student.setAddress(d);
      student.setOSIS(f);
      student.setNumOfCuts(c);
      average = student.paradigm(Double.parseDouble(examGrade1Input.getText()), Double.parseDouble(examGrade2Input.getText()), Double.parseDouble(examGrade3Input.getText()),
      Double.parseDouble(examGrade4Input.getText()), Double.parseDouble(finalExamInput.getText()), Double.parseDouble(homeworkInput.getText()), Double.parseDouble(homeworkCInput.getText()));
      students1[index] = student;
      index++;
      //How can I store the student that was created in an Array?
    }
   
    else if(e.getSource() == button2)
    {
    //How to delete a student through JCombobox
    }
}
  }

---

Code:

---

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JFrame; 
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;


public class BHSSDatabase
{
  public static void main (String[] args)
  {
  //Create and set up the window.
  JFrame frame = new JFrame("The BHSS Database");
  frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
  BHSSDatabasePanelTABBED tabbedPanel = new BHSSDatabasePanelTABBED();
  //Add content to the window.
 
  //Display the window.
    frame.getContentPane().add(tabbedPanel.primary);
    frame.pack();
    frame.setVisible(true);
 
}
}

---

Code:

---

import java.lang.String;

public class StudentClass
{
  private String name, address;
  private int osis, numOfCuts;
  private double finalAvg, exam1, exam2, exam3, exam4, finalExam;
 
  public StudentClass()
  {
    name = "";
    address = "";
    osis = 0;
    numOfCuts = 0;
    finalAvg = 0;
  }
 
 
  public void setName(String name1)
  {
    name = name1;
  }
 
  public String getName()
  {
    return name;
  }
 
  public void setAddress(String address1)
  {
    address = address1;
  }
 
  public String getAddress()
  {
    return address;
  }
 
  public void setOSIS(int osis1)
  {
    osis = osis1;
  }
 
  public int getOSIS()
  {
    return osis;
  }
 
  public void setNumOfCuts(int numOfCuts1)
  {
    numOfCuts = numOfCuts1;
  }
 
  public int getNumOfCuts()
  {
    return numOfCuts;
  }
 
  public double paradigm(double exam1, double exam2, double exam3, double exam4, double finalExam, double hwCompleted, double hwTotal)
  {
    double avg = 0.0;
   
    avg = (((exam1 + exam2 + exam3 + exam4)/(4)) * .7 + (finalExam * .15) + ((hwCompleted/hwTotal)*15));
return avg;
  }
 
  public double paradigm(double exam1, double exam2, double exam3, double finalExam, double projectGrade, double projectTotalPoints, double hwCompleted, double hwTotal)
  {
    double avg = 0.0;
   
    avg = (((exam1 + exam2 + exam3)/3)*.35 + (finalExam*.15) + ((projectGrade/projectTotalPoints)*35) + ((hwCompleted/hwTotal)*15));
    return avg;
  }
 
  public double paradigm(double project1, double project2, double project3, double project4, double project5, double termAbstract, double termProject, double hwCompleted, double hwTotal)
  {
    double avg = 0.0;
    avg = (((((project1 + project2 + project3 + project4 + project5)/1.5) + (termAbstract))/2)*.70) + (termProject * .15) + ((hwCompleted/hwTotal) * 15);
    return avg;
  }
 

   
}

---

Try creating the ComboBox using a model:

Code:

---

filmModel = new DefaultComboBoxModel(days);
filmList = new JComboBox(filmModel);

---

Then, add/remove elements from the model. If the changes are not shown inmediatly, check out the methods validate() and repaint().

Indeed, updating a model should work well and shouldn't even require a call to validate nor repaint. As for the original poster's problems and code, as the saying goes, tl;dr. Have a look at creating and posting an SSCCE.