Controls and layout managers
Components
Combo boxes
A frame with a combo box
Common constructors of the JComboBox class
| Constructor | Description |
|---|---|
| JComboBox() | Creates an empty combo box. |
| JComboBox(Object[]) | Creates a combo box with the objects stored in the specified array. |
Some methods that work with combo boxes
| Method | Description |
|---|---|
| getSelectedItem() | Returns an Object type for the selected item. |
| getSelectedIndex() | Returns an int value for the index of the selected item. |
| setSelectedIndex(intIndex) | Selects the item at the specified index. |
| setEditable(boolean) | If the boolean value is true, the combo box can be edited. |
| getItemCount() | Returns the number of items stored in the combo box. |
| addItem(Object) | Adds an item to the combo box. |
| removeItemAt(int) | Removes the item at the specified index from the combo box. |
| removeItem(Object) | Removes the specified item from the combo box. |
| addActionListener(ActionListener) | Adds an action listener to the combo box. |
| addItemListener(ItemListener) | Adds an item listener to the combo box. |
Code that creates the combo box
private ArrayList<Product> products;
products = getProducts(); // returns an ArrayList of products
productComboBox = new JComboBox();
for (Product p : products)
productComboBox.addItem(p.getDescription());
add(productComboBox);
Code that determines which item was selected
int i = productComboBox.getSelectedIndex(); Product p = products.get(i);