You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 3 Next »

It's common to want the user to confirm his action if it would be hard to reverse, e.g. if he asked to delete something. Here's one way to do this, using Javascript:

Link removeLink = new Link("removeLink") {
			@Override
			public void onClick() {
				// do something you want to confirm beforehand
			}
		};

removeLink.add( new SimpleAttributeModifier("onclick", "return confirm('are you sure?');"));

SimpleAttributeModifier will replace any existing onclick handler in the html. We can instead add our javascript to any existing javascript by attaching an IBehavior object to the Link. First we define a class that implements IBehavior:

class JavascriptEventConfirmation extends AbstractBehavior {
	private final String msg;

	private final String event;

	public JavascriptEventConfirmation(String event, String msg) {
		this.msg = msg;
		this.event = event;
	}

	@Override
	public void onComponentTag(Component component, ComponentTag tag) {
		String script = (String) tag.getAttributes().get(event);
		script = "confirm('" + msg + "'); " + script;
		tag.put(event, script);
	}
}

Then we add the behavior instead of an attribute modifier:

	removeLink.add(new JavascriptEventConfirmation("onclick", "are you sure?"));

If you are using the same confirmation in more than one link, you should subclass Link to encapsulate the change:

abstract public class ConfirmLink extends Link {
      public ConfirmLink(String id, String msg) {
           super(id);
           add(new JavascriptEventConfirmation("onclick", "are you sure?"));
      }

      @Override
      abstract public void onClick();
			
}

(The subclass could of course use SimpleAttributeModifier instead.)

  • No labels