laya2.x的场景Scene和脚本Script

laya2.x UI类结构

- 新增加了一个Scene - > Sprite, Scene只有一个子类就是View，Dialog仍然继承View。

- Component也出现了变化：Component implements ISingletonElement, IDestroy。现在的Component变成了一个脚本的基类，它的子类有相对布局插件

   Widget,Script,CommonScript。之前的Component现在被重命名为UIComponent。

- AnimationPlayerBase被重命名成为AnimationBase

laya1.0创建的UI：xxUI->View->Box->Component->Sprite

laya2.0创建的UI：xxUI->View->Scene->Sprite(创建时也可以选成Scene类型，xxUI->Scene->Sprite)

需要说明一下，现在创建的UI文件后缀名统一为.scene。

laya2.x的Scene类

public function open(closeOther:Boolean = true, param:*=null):void{
  if(closeOther) closeAll();
  root.addChild(scene);
  onOpened(param);  
}
public function close():void{
  if(autoDestroyAtClosed) this.destory();
  else removeSelf();
  onClosed();  
}

override public function destroy(destroyChild:Boolean = true):void{
  _idMap = null;
  super.destroy(destroyChild);
  var list:Array = Scene.unDestroyedScenes;
  for(var i:int = 0, n:int = list.length; i<n;i++){
      if(lsit[i]===this){
        list.splice(i,1);
        return;
      }
   }
}

//创建后，还未被销毁的场景列表，方便查看还未被销毁的场景列表，方便内存管理，本属性只读，请不要直接修改
public static var unDestroyedScenes:Array = [];
public function Scene(){
   this._setBit(Const.NOT_READY,true);
   unDestroyedScenes.push(this);
   this._scene = this;
   createChildren();
}

public static function open(url:String,closeOther:Boolean = true,  complete:Handler = null, param:*=null):void{
  load(url,Handler.create(null,_onSceneLoaded,[closeOther,complete,param]));
}

private static function _onSceneLoaded(closeOther:Boolean,complete:Handler,param:*,scene:Scene):void{
    scene.open(closeOther,param);
    if (complete) complete.runWith(scene);
}

public static funcion close(url:String,name:String= ""):Boolean{
   var flag:Boolean = false;
   var list:Array  = Scene.unDestroyedScenes;
    for (var i:int=0,n:int=list.length;i<n;i++){
     var scene:Scene = list[i];
     if (scene.parent && scene.url === url && scene.name == name){
    scene.close();
    flag = true;
       }
    }
    return flag;
}

public static function closeAll():void {
    var root:Sprite = Scene.root;
    for (var i:int = 0, n:int = root.numChildren;i<n;i++){
      var scene:Scene = root.getChildAt(0) as Scene;
      if (scene is Scene) scene.close();
   }
}

public static function destroy(url:String,name:String=""):Boolean{
  var flag:Boolean = false;
  var list:Array = Scene.unDestroyedScenes;
  for (var i:int=0,n:int=list.length;i<n;i++){
       var scene:Scene = list[i];
       if (scene.url ===url && scene.name == name){
         scene.destroy();
         flag = true;
       }
   }
    return flag;
}

public static function get root():Sprite{
     if(!_root){
       _root = Laya.stage.addChild(new Sprite()) as Sprite;
       _root.name = "root";
       Laya.stage.on("resize",null,resize);
       function resize():void{
           _root.size(Laya.stage.width, Laya.stage.height);
           _root.event(Event.RESIZE);
           }
      resize();
      }
      return _root;
}

1. autoDestroyAtClosed : 场景被关闭后，是否自动销毁（销毁节点和使用到的资源）,默认为false

在close方法中，可以看到if (autoDestroyAtClosed) this.destroy();

2.在open方法中，看到root.addChild(scene);,而在get root中看到_root = Laya.stage.addChild(new Sprite()) as Sprite,这说明所有打开的Scene都被添加到一个叫root的Sprite容器里，这个容器是直接放在stage上了。

3.参考一下官方例子中如何使用scene的：

static startScene:any = "test/Test2View.scene";
Laya.Scene.open(GameConfig.startScene);

这里直接调用static open方法，在里面调用了load方法

public static function load(url:String,complete:Handler = null):void{
      Laya.loader.resetProgress();
      var loader:SceneLoader = new SceneLoader();
      loader.on(Event.COMPLETE,null,create);
      loader.load(url);
      
      function create():void {
        var obj:Object = Loader.getRes(url);
        if(!obj) throw "Can not find scene:" + url;
        if(!obj.props) throw "Scene data is error:" + url;
         var runtime:String = obj.props.runtime ? obj.props.runtime : obj.type;
         var clas:*=ClassUtils.getClass(runtime);
         if(obj.props.renderType=="instance"){
                var scene:Scene = clas.instance || (clas.instance = new clas());
                } else {
                 scene = new clas();
               }
         if (scene && scene is Node){
               scene.url = rul;
               if (!scene._getBit(Const.NOT_READY)) complete.runWith(scene);
               else{
                    scene.on("onViewCreated",null,functon():void{
                          complete && complete.runWith(scene)
                          })
                          scene.createView(obj);
                     }
           }else{
                throw "Can not find scene:" + runtime;
            }
       }
}

　

牵涉到SceneLoader类

public static const LoadableExtensions:Object = {"scene":Loader.JSON}

这个映射会把test/Test2View.scene转化为去加载相应的json文件

Dialog

laya2.x创建的Dialog:xxDialogUI - > Dialog - > View - > Scene - > Sprite

Dialog会把Scene中默认的open方法覆盖掉，转交给DialogManager处理

//Dialog:
override public function open(closeOther:Boolean = true, param:* = null):void {
    _dealDragArea();
    _param=param;
    manager.open(this, closeOther, isShowEffect);
    manager.lock(false);
}

//DialogManager:
public class DialogManager extends Sprite

public function DialogManager() {
    this.mouseEnabled = maskLayer.mouseEnabled = true;
    this.zOrder = 1000;
    
    Laya.stage.addChild(this);
    Laya.stage.on(Event.RESIZE, this, _onResize);
    if (UIConfig.closeDialogOnSide) maskLayer.on("click", this, _closeOnSide);
    _onResize(null);
}

public function open(dialog:Dialog, closeOther:Boolean = false, showEffect:Boolean=false):void {
    if (closeOther) _closeAll();
    if (dialog.isPopupCenter) _centerDialog(dialog);
    addChild(dialog);
    if (dialog.isModal || this._getBit(Const.HAS_ZORDER)) Laya.timer.callLater(this, _checkMask);
    if (showEffect && dialog.popupEffect != null) dialog.popupEffect.runWith(dialog);
    else doOpen(dialog);
    event(Event.OPEN);
}

总结：可以把Scene看做是官方提供的一个场景管理器，像closeOther,closeAll,onOpened,onClosed都是很实用的。

实例：添加按钮切换场景

LayaAir2.x开发思路为组件化，脚本化，场景管理开发，项目采用scene管理方式，来管理场景，LayaAir已经对scene做了一系列方案，使得开发者无需考虑场景，关卡，页面的资源，内存管理，只需要单纯的调用接口，管理场景，其它的交给引擎去做，只需要专注游戏逻辑开发即可。

1.先新建一个脚本

2.在Start.scene中放一个按钮，就可以添加组件了，这样运行时，点击按钮，就会触发onClick方法打开box2d.scene场景。

3.按F9设置启动场景为Start.scene,现在运行后就能看到场景切换效果了。

4.在GameConfig的init方法中就可以看到

static init(){
    var reg: Function = Laya.ClassUtils.regClass;
    reg("script/Start.ts",Start);
}
//ClassUtils:
public static function regClass(className:String, classDef:*):void {
    _classMap[className] = classDef;
}

注：参考文章https://www.jianshu.com/p/5701f9f854fa