-- 全局缓存，会在退出时自动销毁
local UICache = cc.RefObjectCache:create();

-- 从缓存中加载ui
function loadUIFromCache(filename)
	local ui = UICache:pop(filename);
	if ui == nil then
		print("加载ui:" , filename);
		ui = loadUI(filename);
		local function onNodeEvent(node , eventType)
			if eventType == cc.NodeEvent.OnEnter then
			elseif eventType == cc.NodeEvent.OnExit then
				print("回收ui：" , filename);
				ui:removeAllChildrenTouchEvent()
				UICache:push(filename , ui);
			end
		end
		ui:addNodeEventListener(onNodeEvent)
	else
		print("从缓存中获取ui:" , filename);
	end
	return ui;
end