Key Events

From Documentation


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Users can write key event listeners for key events such as ctrl+C, ctrl+V and so on.

Purpose

Implement onCtrlKey event listener.

Key event

Key event represents a key pressed by the user.

  • onCtrlKey - This event is fired when the user presses a key along with a ctrl key. Event listeners are provided with KeyEvent in the event listener.

Registering Key Events

Key event can be registered to ZK Spreadsheet by calling AbstractComponent.addEventListener(String, EventListener) as shown below.

...
ss.addEventListener(org.zkoss.zk.ui.event.Events.ON_CTRL_KEY,
		new EventListener() {
			public void onEvent(Event event) throws Exception {
				doCtrlKeyEvent((KeyEvent) event);
			}
		});
...

Note: Here instead of onCtrlKey a corresponding static constant declared in org.zkoss.zk.ui.event.Events class is used.

ZUML

Here is a sample example of ZUL file.

<?page title="ZSS" contentType="text/html;charset=UTF-8"?>
<zk>
	<window title="ZSS Key Events" border="normal" width="100%"
		height="100%"
		apply="org.zkoss.zssessentials.events.KeyEventsComposer">
		<hlayout>
			<label value="Key code:"></label>
			<textbox id="editBox"></textbox>
		</hlayout>
		<spreadsheet id="ss" width="800px" height="800px" maxrows="20"
			maxcolumns="10" src="/WEB-INF/excel/events/events.xlsx"
			ctrlKeys="^c^x^v">
		</spreadsheet>
	</window>
</zk>

Above we register ctrl+c,ctrl+x and ctrl+v key events.

Composer

Here is the composer code

public class KeyEventsComposer extends GenericForwardComposer {

	private transient Spreadsheet ss;
	private transient Textbox editBox;

	public void doAfterCompose(Component comp) throws Exception {
		super.doAfterCompose(comp);
		ss.addEventListener(org.zkoss.zk.ui.event.Events.ON_CTRL_KEY,
				new EventListener() {
					public void onEvent(Event event) throws Exception {
						doCtrlKeyEvent((KeyEvent) event);
					}
				});
	}

	private void doCtrlKeyEvent(KeyEvent event) {
		editBox.setValue("" + event.getKeyCode());
		char c = (char) event.getKeyCode();
		switch (c) {
		case 'X':
			// do cut operation
			break;
		case 'C':
			// do copy operation
			break;
		case 'V':
			// do paste operation
			break;
		default:
			return;
		}
	}
}

You can retrieve key pressed from KeyEvent using KeyEvent.getKeyCode(). View the complete source code for composer here

Version History

Last Update : 2022/01/19


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All source code listed in this book is at Github.

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.