Libgdx 之Actor 演员类

教程总目录： http://blog.csdn.net/zqiang_55/article/details/50878524

上一篇我们介绍了Libgdx中舞台类，按照类的继承图，我们应该介绍Actor类，从截图中我们知道Libgdx中的UI控件都是继承自Actor。
前面我们也介绍过Sprite类，Actor有点类似于Sprite类，保存位置，大小，颜色，旋转中心，缩放以及Actions等，同时里面也包含了一个舞台类。Actor的坐标系(local Coordinate)从左下角开始计算
我们在初始化Actor时可以设置Listener，处理一些监听事件。

注意：1. Actor的draw函数默认是空的，需要重写。
2./** Called by the framework when this actor or any parent is added to a group that is in the stage.
* @param stage May be null if the actor or any parent is no longer in a stage. */
protected void setStage (Stage stage) {
this.stage = stage;
}
3. 此外还有一个函数需要注意：
/* Set bounds the x, y, width, and height. /
public void setBounds (float x, float y, float width, float height)

测试代码：

    Stage stage;
    MyActor myActor;

    @Override
    public void create() {
        stage = new Stage();
        Gdx.input.setInputProcessor(stage);

        myActor = new MyActor();
        yActor.setX(Gdx.graphics.getWidth() / 2 - myActor.getWidth() / 2);
        myActor.setY(Gdx.graphics.getHeight() / 2 - myActor.getHeight() / 2);
        stage.addActor(myActor);
    }

    @Override
    public void render() {
        Gdx.gl.glClearColor(0.39f, 0.58f, 0.92f, 1.0f);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        stage.act();
        stage.draw();
    }

    @Override
    public void dispose() {
        stage.dispose();
        myActor.dispose();
    }

    public class MyActor extends Actor implements Disposable {
        TextureRegion region;

        public MyActor() {
            region = new TextureRegion(new Texture("badlogic.jpg"));

            setSize(this.region.getRegionWidth(), this.region.getRegionHeight());

            // 设置监听函数，可以处理一些事情
            addListener(new ClickListener() {

                @Override
                public void clicked(InputEvent event, float x, float y) {
                   //点击图片，图片隐藏![这里写图片描述](http://img.blog.csdn.net/20160425220710777)
                    setVisible(false);
                    super.clicked(event, x, y);
                }
            });
        }

        @Override
        public void draw(Batch batch, float parentAlpha) {
            super.draw(batch, parentAlpha);

            batch.draw(region, getX(), getY(), 
                    getOriginX(), getOriginY(), 
                    getWidth(), getHeight(), 
                    getScaleX(), getScaleY(), 
                    getRotation());
            }

        @Override
        public void dispose() {
            region.getTexture().dispose();
        }

    }