How to show up iOS UI dialog with cocos2d-x ?

I have a question on how to do UI based stuff with c++ (of course, cocos2d-x).

Is that UI part needed to be programmed with objective-c or we can do it via cocos2d-x methods ?

I need some suggestions, thanks so much !

Cocos2d is a graphic render framework, with only few UI components.
Of course you can combine iOS UIKit and cocos2d-x in iOS games, but considering the multi-platform design, most developers rewrote their UI components based on cocos2d-x, exactly inherited from CCLayer.
Another way is to integrate with other OpenGL ES based UI libraries, such as GUIChain and CEGUI.