[]分享个资源加载的方法，类似白鹭的加载方式

class RES extends Laya.EventDispatcher{

    // 资源组

    public static groups: any;

    // 资源

    public static resources: any;

    // 完成加载资源配置文件

    public static ONLOADEDRESJSON: string = "onLoadedResJson";

    // 资源配置文件加载出错

    public static ONLOADERRORRESJSON: string = "onLoadError";

    // 资源组加载完成

    public static ONLOADGROUPCOMPLETE: string = "onLoadGroupConplete";

    // 资源组加载出错

    public static ONLOADGROUPERROR: string = "onLoadGroupError";

    private static _res:RES;

    public static getInstance():RES{

        if(!RES._res){

            RES._res = new RES();

        }

        return RES._res;

    }

    /**

     * 加载资源配置文件

     */

    public static loadResJson(srcName: string,caller: any){

        Laya.loader.load("res/" + srcName,new Laya.Handler(caller,function(arg: any){

            if(arg){

                RES.groups = arg.groups;

                RES.resources = arg.resources;

                RES.getInstance().event(RES.ONLOADEDRESJSON,arg);

            }else{

                RES.getInstance().event(RES.ONLOADERRORRESJSON,arg);

            }

        }))

    }

    /**

     * groupName 资源组名称

     */

    public static loadGroup(groupName: string){

        if(!groupName){

            console.error("资源组名称不能为空");

            RES.getInstance().event(RES.ONLOADGROUPERROR,"资源组名称不能为空");

            return;

        }

        var group;

        for(var i in RES.groups){

            var name = RES.groups[i].name;

            if(name == groupName){

                group = RES.groups[i];

                break;

            }

        }

        if(!group){

            console.error("加载了不存在的资源组");

            RES.getInstance().event(RES.ONLOADGROUPERROR,"加载了不存在的资源组");

            return;

        }

        var keys: string = group.keys;

        if(!keys){

            console.error(group.name + "资源组资源为空");

            RES.getInstance().event(RES.ONLOADGROUPERROR,group.name + "资源组资源为空");

            return;

        }

        var allKey: string = keys.split(",");

        var assets: any = ;

        for(var k = 0;k<allKey.length;k++){

            var key = allKey[k];

            for(var j in RES.resources){

                if(RES.resources[j].name == key){

                    assets.push(RES.resources[j]);

                }

            }

        }

        Laya.loader.load(assets,new Laya.Handler(this,function(arg){

            RES.getInstance().event(RES.ONLOADGROUPCOMPLETE,arg);

        }))

        

    }



    /**

     * 获取资源 resName 资源名  isAtLas 是否是图集

     */

    public static getRes(resName:string, isAtLas: boolean = false): any{

        var url: string;

        if(!isAtLas){

            for(var j in RES.resources){

                if(RES.resources[j].name == resName){

                    url = RES.resources[j].url;

                    break;  

                }

            }

        }else{

            url = resName;

        }

        var src = Laya.Loader.getRes(url);

        return src;

    }

}[/i][/i]