在实际项目制作过程中，***有时候仅仅播放预先设置的骨骼动画是不够的，还需要角色具有动态可控的动作。DragonBones提供了访问并控制骨骼框架里的每一根骨头的方法，可以让角色能够有丰富多样的交互效果。***

  在示例中，通过鼠标拖拽方块，小龙人根据与方块的距离去播放stand或者walk的动画，根据与方块的角度问题，小龙人的头部与手部会有一个角度的变化。

本需求的重点就是：获取头部与手部的骨骼，然后设置骨骼的旋转角度。

本示例的关键代码如下：

private head: dragonBones.Bone;
private armL: dragonBones.Bone;
private armR: dragonBones.Bone;
//获取骨骼
this.head = this.armature.getBone("head");
this.armL = this.armature.getBone("armUpperL");
this.armR = this.armature.getBone("armUpperR");

通过dragoneBones.Armature.getBone("骨骼名字")来获取某个骨骼，骨骼对象中的offset属性是一个DBTranform对象，是专门用于给开发者设置叠加的变换信息的，包括平移，旋转，缩放等。

this.head.offset.rotation = _r *0.3       
this.armR.offset.rotation = _r *0.8;
this.armL.offset.rotation = _r * 1.5;

ps:这里的offset的值是叠加到骨骼现有的变化上，并不是取代骨骼的现有变换。

下面是整个示例的完整代码：

/**
 * 该类主要是用来学习 如何控制骨骼动画中骨骼的运动
 */
class DBTestScene2  extends egret.Sprite{
    // private factory:dragonBones.EgretFactory;
    // private armature:dragonBones.Armature;//骨架
    // private armatureDisplay:dragonBones.EgretArmatureDisplay;//骨架显示对象
    // private head:dragonBones.Bone;//头骨骼
    // private armL:dragonBones.Bone;//左臂骨骼
    // private armR:dragonBones.Bone;//右臂骨骼
    // private bird:egret.Shape;

    public constructor() {
        super();
        this.addEventListener(egret.Event.ADDED_TO_STAGE,this.onStage,this);

    }

    private onStage(){
        this.graphics.beginFill(0xff0000,0.3);
        this.graphics.drawRect(0,0,this.stage.stageWidth,this.stage.stageHeight);
        this.graphics.endFill();

        this.initGame();

    }

    private factory:dragonBones.EgretFactory = new dragonBones.EgretFactory();
    private armature: dragonBones.Armature;
    private armatureClip:egret.DisplayObject;
    private head: dragonBones.Bone;
    private armL: dragonBones.Bone;
    private armR: dragonBones.Bone;
    private lark: egret.Bitmap;
    private initGame(): void 
    {
        // 获取骨骼数据
        var skeletonData = RES.getRes("Dragon_ske_json");
        // 获取纹理数据
        var textureData = RES.getRes("Dragon_tex_json");
        var texture = RES.getRes("Dragon_tex_png");
        // 解析骨骼数据与纹理数据
        this.factory.parseDragonBonesData(skeletonData);
        this.factory.parseTextureAtlasData(textureData,texture);
        
        // 获取骨架
        this.armature = this.factory.buildArmature("Dragon");
        // 注意！！！！！这里要获取骨架上的display 才可以在骨架移动的时候贴图一起移动
        this.armatureClip = this.armature.getDisplay();
        // 如果这样子获取armatureDisplay 骨骼移动之后 贴图并不会动
        // this.armatureClip = this.factory.buildArmatureDisplay("Dragon");
        this.armatureClip.x = 200;
        this.armatureClip.y = 450;
        this.addChild(this.armatureClip);
        
        dragonBones.WorldClock.clock.add(this.armature);

        this.armature.animation.play("stand");

        this.head = this.armature.getBone("head");
        this.armL = this.armature.getBone("armUpperL");
        this.armR = this.armature.getBone("armUpperR");
     
        egret.startTick(this.onTicker, this);

        this.stage.addEventListener(egret.TouchEvent.TOUCH_MOVE,this.onTouchMove,this);
        this.lark = new egret.Bitmap(RES.getRes("button_down_png"));
        this.addChild(this.lark);
    }

    private _time:number;

    private onTicker(timeStamp:number) {

        if(!this._time) {
            this._time = timeStamp;
        }

        var now = timeStamp;
        var pass = now - this._time;
        this._time = now;

        this.checkDist();
        this.updateMove();
        this.updateBones();

        dragonBones.WorldClock.clock.advanceTime(pass / 1000);

        return false;
    }

    
    private mouseX: number = 0;
    private mouseY: number = 0;
    private dist: number = 0;
    private moveDir: number = 0;
    private speedX: number = 0;
    private onTouchMove(evt: egret.TouchEvent): void
    {
        this.mouseX = evt.stageX;
        this.mouseY = evt.stageY;
        this.lark.x=this.mouseX - 39;
        this.lark.y=this.mouseY - 34;
    }
    private checkDist():void
    {
        this.dist = this.armatureClip.x-this.mouseX;
        if(this.dist<150)
        {
            this.updateBehavior(1);
        }
        else if(this.dist>190)
        {
            this.updateBehavior(-1)
        }
        else
        {
            this.updateBehavior(0)
        }
                    
    }
    private updateBehavior(dir:number):void
    {
        if(this.moveDir == dir) {
            return;
        }
        this.moveDir=dir;
        if (this.moveDir == 0)
        {
            this.speedX = 0;
            this.armature.animation.gotoAndPlay("stand");
        }
        else
        {
            this.speedX=6*this.moveDir;
            this.armature.animation.gotoAndPlay("walk");
        }
    }
    private updateMove():void
    {
        if (this.speedX != 0) 
        {
            this.armatureClip.x += this.speedX;
            if (this.armatureClip.x < 0) 
            {
                this.armatureClip.x = 0;
            }
            else if (this.armatureClip.x > 800) 
            {
                this.armatureClip.x = 800;
            }
        }
    }
    private updateBones():void
    {
        //update the bones' pos or rotation
        var _r = Math.PI + Math.atan2(this.mouseY - this.armatureClip.y+this.armatureClip.height/2, this.mouseX - this.armatureClip.x);
        if (_r > Math.PI)
        {
            _r -= Math.PI * 2;
        }
        this.head.offset.rotation = _r *0.3       
        this.armR.offset.rotation = _r *0.8;
        this.armL.offset.rotation = _r * 1.5;
        this.lark.rotation=_r*0.2;
    }


   

}