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The Java Developers Almanac 1.4 |
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e762. Displaying the Menu in a JComboBox Component Using a KeystrokeBy default, typing a key in a read-only combobox selects an item that starts with the typed key. This example demonstrates how to display the drop-down menu when a key is typed. // Create a read-only combobox
String[] items = {"Ant", "Ape", "Bat", "Boa", "Cat", "Cow"};
JComboBox cb = new JComboBox(items);
// Create and register the key listener
cb.addKeyListener(new MyKeyListener());
// This key listener displays the menu when a key is pressed.
// To display the menu only if the pressed key matches or does not match an item,
// see e763 Displaying the Menu in a JComboBox Component Using a Keystroke If the Selected Item Is Not Unique.
class MyKeyListener extends KeyAdapter {
public void keyPressed(KeyEvent evt) {
JComboBox cb = (JComboBox)evt.getSource();
// Get pressed character
char ch = evt.getKeyChar();
// If not a printable character, return
if (ch != KeyEvent.CHAR_UNDEFINED) {
cb.showPopup();
}
}
}
e757. Getting and Setting the Selected Item in a JComboBox Component e758. Getting the Items in a JComboBox Component e759. Adding and Removing an Item in a JComboBox Component e760. Selecting an Item in a JComboBox Component with Multiple Keystrokes e761. Determining If the Menu of a JComboBox Component Is Visible e763. Displaying the Menu in a JComboBox Component Using a Keystroke If the Selected Item Is Not Unique e764. Setting the Number of Visible Items in the Menu of a JComboBox Component e765. Listening for Changes to the Selected Item in a JComboBox Component e766. Listening for Action Events from a JComboBox Component e767. Determining When the Menu of a JComboBox Component Is Displayed © 2002 Addison-Wesley. |