CitrusEngine横版游戏开发教程（四）Entity

这一节我给大家介绍一下citrus.system.Entity

Entity类可以自由的组合行为，使用方式类似装饰者模式，但却有别于装饰者

_heroEntity = new Entity("heroEntity");

_physics = new DraggableHeroPhysicsComponent("physics", {x:200, y:270, width:40, height:60});
var input:InputComponent = new InputComponent("input");
var collision:HeroCollisionComponent = new HeroCollisionComponent("collision");
var move:HeroMovementComponent = new HeroMovementComponent("move");
_view = new HeroViewComponent("view", {view:"PatchSpriteArt.swf"});

_heroEntity.add(_physics).add(input).add(collision).add(move).add(_view);
_heroEntity.initialize();

addEntity(_heroEntity, _view);

为了方便理解 ，下面我来模拟一下Entity的实现 

Entity类：

package com.decorator
{
    import flash.display.Sprite;

    /**
     * @author cong   QQ:19312413
     */
    public class Entity extends Sprite
    {
        public function Entity()
        {
        }
        
        public function initialize():void
        {
            trace("我是实体");
        }
    }
}

Behavior类

package com.behavior
{
    /**
     * @author cong   QQ:19312413
     */
    public class Behavior
    {
        public var entity:Entity;
        public function Behavior()
        {
        }
        
        public function initialize():void
        {
            if(entity!=null)
            {
                trace("行为初始化");
            }
        }
    }
}

下面我们创建两个行为类

package com.behavior
{

    /**
     * @author cong   QQ:19312413
     */
    public class TalkBehavior extends Behavior
    {
        public function TalkBehavior()
        {
        }
        
        override public function initialize():void
        {
            trace("我会说话");
        }
    }
}

package com.behavior
{

    /**
     * @author cong   QQ:19312413
     */
    public class WalkBehavior extends Behavior
    {
        public function WalkBehavior()
        {
        }

        override public function initialize() : void
        {
            trace("我会走路");
        }
    }
}

文档类：

package
{
    import com.behavior.Entity;
    import com.behavior.TalkBehavior;
    import com.behavior.WalkBehavior;
    import flash.display.Sprite;

    /**
     * @author cong   QQ:19312413
     */
    public class BehaviorTest extends Sprite
    {
        public function BehaviorTest()
        {
            var entity:Entity = new Entity();
            var walkBehavior:WalkBehavior = new WalkBehavior();
            var talkBehavior:TalkBehavior = new TalkBehavior();
            entity.addBehavior(walkBehavior).addBehavior(talkBehavior);
            entity.initialize();
        }
    }
}