export default class LayerManager
{
    /**
     * 添加内容到层
     * @param layerIndex 
     * @param node 
     */
    AddToLayer(layerIndex:number,node:fgui.GComponent):void{
        let layer:fgui.GComponent=this.GetLayer(layerIndex);
        if(layer==null){
            throw new Error("找不到："+layerIndex+"层！");
        }
        layer.addChild(node);
    }

    /**
     * 从层上删除内容
     * @param layerIndex 
     * @param node
     */
    RemoveFormeLayer(layerIndex:number,node:fgui.GComponent):void{
        let layer:fgui.GComponent=this.GetLayer(layerIndex);
        if(layer==null){
            throw new Error("找不到："+layerIndex+"层！");
        }
        layer.removeChild(node);
    }

    /**
     * 通过层索引获取层
     * @param layerIndex 
     */
    GetLayer(layerIndex:number):fgui.GComponent{
        let layer:fgui.GComponent=fgui.GRoot.inst.getChildAt(layerIndex).asCom;
        if(layer==null){
            throw new Error("找不到："+layerIndex+"层！");
        }
        return layer;
    }
    
    /**
     * 单例
     */
    private static instance:LayerManager;
    public static get single():LayerManager{
        if(this.instance==null){
            this.instance=new LayerManager();
        }
        return this.instance;
    }
}