Create ComboBox in Java:
| We can use the Eclipse IDE for this example. If you do not know about it then follow this link- How to Install Eclipse For Java and create a program in it. |
A JComboBox is a component that combines two features: a display area showing a default option and a list box that contains additional, alternate options. (A list box is also known as a ComboBox or a drop-down list). The display area contains either a button that a user can click or an editable field into which the user can type. When a JComboBox appears on the screen, the default option is displayed. When the user clicks the JComboBox, a list of alternative items drop-down; if the user selects one, it replaces the box’s displayed item.
Java ComboBox Methods:
| Method | Description |
|---|---|
| int getItemCount( ) | Returns the number of items in the list. |
| int getMaximumRowCount( ) | Returns the maximum number of items the ComboBox can display without a scroll bar. |
| int getSelectedIndex( ) | Returns the index of the selected item. |
| Object getSelectedItem( ) | Returns the selected item as an Object. |
| void removeItem(Object obj ) | Removes the object from the list. |
| void removeItemAt(int index) | Removes the object at the specified index. |
| void setBackground(Color) | Sets the background color. |
| void setEditable(boolean) | Sets the field to be editable or not editable. |
| void setSelectedIndex( int) | Sets the index at the position indicated by the argument. |
| void setSelectedItem (Object) | Sets the selected item in the ComboBox display area to be the Object argument. |
| void setOpaque(boolean) | Sets background as transparent (boolean is false) or solid (boolean is true). |
Sample Code to Create ComboBox in Java:
Output:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Combobox extends JFrame implements ActionListener{
JComboBox combo_box;
Combobox(){
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(new FlowLayout());
String [] flowers = {"Rose", "Lotus", "Sun Flower", "Marigold"};
combo_box = new JComboBox(flowers);
combo_box.addActionListener(this);
this.add(combo_box);
this.pack();
this.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource()==combo_box) {
System.out.println(combo_box.getSelectedItem());
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
new Combobox();
}
}
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