How to Create Combo Box : Java Swing Example

You will learn how to insert combo-box using Swing in Java. Combox box is used display item in drop down list. It provides option to select an item from the drop down. The basic difference between combo box and list box is that user cannot select multiple item from combo-box but it can be possible in list box.


import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ComboBox{
JComboBox combo;
JTextField txt;
public static void main(String[] args) {
ComboBox b = new ComboBox();
}

public ComboBox(){
String course[] = {"India","Germany","America","Russia"};
JFrame frame = new JFrame("Creating a JComboBox Component");
JPanel panel = new JPanel();
combo = new JComboBox(course);
combo.setBackground(Color.gray);
combo.setForeground(Color.red);
txt = new JTextField(10);
panel.add(combo);
panel.add(txt);
frame.add(panel);
combo.addItemListener(new ItemListener(){
public void itemStateChanged(ItemEvent ie){
String str = (String)combo.getSelectedItem();
txt.setText(str);
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400,400);
frame.setVisible(true);
}
}

Maximize a Frame using Swing

In this program, you will learn how to maximize a frame using setMaximizedBounds() to set the bounds for a maximized frame. Here is the source code :

import java.awt.*;
import javax.swing.*;

public class SwingSetBounds{
public static void main(String[] args){
JFrame frame = new JFrame();
Rectangle bounds = new Rectangle(0, 0, 500, 500);
frame.setMaximizedBounds(bounds);
frame.setSize(400, 400);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}