FocusListener.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.scenes.scene2d.utils;

import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.Event;
import com.badlogic.gdx.scenes.scene2d.EventListener;

/**
 * Listener for {@link FocusEvent}.
 * 
 * @author Nathan Sweet
 */
abstract public class FocusListener implements EventListener {
	public boolean handle(Event event) {
		if (!(event instanceof FocusEvent))
			return false;
		FocusEvent focusEvent = (FocusEvent) event;
		switch (focusEvent.getType()) {
		case keyboard:
			keyboardFocusChanged(focusEvent, event.getTarget(), focusEvent.isFocused());
			break;
		case scroll:
			scrollFocusChanged(focusEvent, event.getTarget(), focusEvent.isFocused());
			break;
		}
		return false;
	}

	/**
	 * @param actor
	 *            The event target, which is the actor that emitted the focus event.
	 */
	public void keyboardFocusChanged(FocusEvent event, Actor actor, boolean focused) {
	}

	/**
	 * @param actor
	 *            The event target, which is the actor that emitted the focus event.
	 */
	public void scrollFocusChanged(FocusEvent event, Actor actor, boolean focused) {
	}

	/**
	 * Fired when an actor gains or loses keyboard or scroll focus. Can be cancelled to prevent losing or gaining focus.
	 * 
	 * @author Nathan Sweet
	 */
	static public class FocusEvent extends Event {
		private boolean focused;
		private Type type;
		private Actor relatedActor;

		public void reset() {
			super.reset();
			relatedActor = null;
		}

		public boolean isFocused() {
			return focused;
		}

		public void setFocused(boolean focused) {
			this.focused = focused;
		}

		public Type getType() {
			return type;
		}

		public void setType(Type focusType) {
			this.type = focusType;
		}

		/**
		 * The actor related to the event. When focus is lost, this is the new actor being focused, or null. When focus
		 * is gained, this is the previous actor that was focused, or null.
		 */
		public Actor getRelatedActor() {
			return relatedActor;
		}

		/**
		 * @param relatedActor
		 *            May be null.
		 */
		public void setRelatedActor(Actor relatedActor) {
			this.relatedActor = relatedActor;
		}

		/** @author Nathan Sweet */
		static public enum Type {
			keyboard, scroll
		}
	}
}