Adding String to ArrayList from textfield and showing it on ComboBox

[Renxx]

How can i make so that when i add String to ArrayList from textfield, it adds it automaticlyto JComboBox as one of the options which to choose.

package Leiutis;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;


import javax.swing.*;

public class AddArray {

   static ArrayList<String> al = new ArrayList<String>();
   static int count =-1;
   static String sum ="";
   
   public static void main(String[] args) {
      final GUIx s = new GUIx();
      s.setVisible(true);
      s.getButton().addActionListener(new ActionListener() {
         
         public void actionPerformed(ActionEvent e) {
          al.add(s.getTField().getText());
          sum += s.getTField().getText()+" ";
         }
         
      });
      s.getButtonx().addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            if(al.size()<1)
               s.getLabel().setText("Nimekiri tühi");
            else {
                  s.getLabel().setText(sum) ;
               
            }
         
         }
         
      });
      s.getCombo().addItemListener(new ItemListener() {

         @Override
         public void itemStateChanged(ItemEvent e) {
            // TODO Auto-generated method stub
            
         }
         
      });
   }
   

}

class GUIx extends JFrame {
      
   private FlowLayout layout;
   private Button button,buttonx;
   private Label label;
   private TextField tfield;
   private JComboBox combo;
   
   public Button getButtonx() {
      return buttonx;
   }
   
   public JComboBox getCombo() {
      return combo;
   }
   
   public Button getButton() {
      return button;
   }
   public TextField getTField() {
      return tfield;
   }
   public Label getLabel() {
      return label;
   }
   
      
   
   GUIx() {
      super("thetitle");
      setSize(300,300);
      layout = new FlowLayout();
      getContentPane().setBackground(new Color(255,0,0));
      setLayout(layout);
      setDefaultCloseOperation(EXIT_ON_CLOSE);
   
      button = new Button("Add");
      button.setBackground(new Color(0,255,0));
      add(button);
      
      buttonx = new Button("Display");
      buttonx.setBackground(new Color(0,200,0));
      add(buttonx);
      
      tfield = new TextField(10);
      tfield.setFont(new Font("Serif",Font.BOLD,14));
      add(tfield);
      
      label = new Label();
      add(label);
      
      combo = new JComboBox(AddArray.al.toArray());
      add(combo);
      
      
   }
   
   
}

[Fubarable]

I wouldn't use an ArrayList but rather to keep it simple, use a DefaultComboBoxModel like so:

class GUIx extends JFrame {
   // ..... code deleted for brevity

   //!! added
   private DefaultComboBoxModel comboModel = new DefaultComboBoxModel();
   private JComboBox combo = new JComboBox(comboModel); //!! changed

Then I'd give GUIx two public methods, one to add and element to the comboModel and one to get the comboModel's size:

   //!! added
   public void addElement(Object element) {
      comboModel.addElement(element);
   }
   
   //!! added
   public int getComboSize() {
      return comboModel.getSize();
   }

Then I would have to change the GUIx constructor a little since the combo box has already been constructed.:

      //!! combo = new JComboBox(AddArray.al.toArray());
      add(combo);

Then in the main program, I'd use the methods just created:

      s.getButton().addActionListener(new ActionListener() {

         public void actionPerformed(ActionEvent e) {
            //!!
            String text = s.getTField().getText(); //!!
            s.addElement(text); //!!
            
            //!! al.add(s.getTField().getText());
            sum += s.getTField().getText() + " ";
         }

      });
      s.getButtonx().addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            //!! if (al.size() < 1)
            if (s.getComboSize() < 1) //!!
               s.getLabel().setText("Nimekiri tühi");
            else {
               s.getLabel().setText(sum);

            }

         }

      });