How do I create a message box that fires a callback on button press?

I need too often to show popup message in my games. so I've created a base class and I derived new popup message class from it and override SetupUI() in derived class to show my desired message. in fact you need to put a MenuItem in SetupUI() of new class to implement "ok" button simply.

Note: CreateInvisibleBackgroundButton() works for cocos2dx v2.x and BlockPassingTouch() is its equivalent for cocos2dx v3.x .

Note2: If you want to call different callback for same popup message, you can pass a callback std::function<void(void)> _callbackFunc (cocos2dx v3) as parameter to your dialog and call that when "ok" pressed.

If you need more description just tell me.

PopupNode.h

#ifndef __POPUP_NODE_H__
#define __POPUP_NODE_H__

#include "cocos2d.h"

class PopupNode : public cocos2d::Node
{
public:
    CREATE_FUNC(PopupNode);
    virtual bool init();    // subclass should have access to call it
    void ClosePopup();
private:
    void BlockPassingTouch();
    void SetupUI();
    void CreateInvisibleBackgroundButton(); //THIS FUNCTION IS OUTDATED. KEEP FOR COMPARING COCOS2D 2.X AND 3.X
};

#endif // __POPUP_NODE_H__

PopupNode.cpp

#include "PopupNode.h"
#include "Const/constants_z_order.h"

USING_NS_CC;


bool PopupNode::init()
{
    if ( !Node::init() )
    {
        return false;
    }
    //////////////////////////////////////////////////////////////////////////
    BlockPassingTouch(); //CreateInvisibleBackgroundButton();
    SetupUI();
    //////////////////////////////////////////////////////////////////////////
    return true;
}

void PopupNode::CreateInvisibleBackgroundButton()
{
    // Code below works with cocos2dx 2.x
    //////////////////////////////////////////////////////////////////////////
    ///////// THIS FUNCTION IS OUTDATED. KEEP FOR COMPARING COCOS2D 2.X AND 3.X
    //////////////////////////////////////////////////////////////////////////
    //////////////////////////////////////////////////////////////////////////
//  Size visibleSize = Director::getInstance()->getVisibleSize();
//  Vec2 origin = Director::getInstance()->getVisibleOrigin();
//  //////////////////////////////////////////////////////////////////////////
//  auto lock_menu = Menu::create();
//  //lock_menu->setTouchPriority(-1000); // get touch first
//  lock_menu->setPosition(origin);
//  this->addChild(lock_menu);
//  //////////////////////////////////////////////////////////////////////////
//  auto invisibleClose = MenuItemSprite::create(NULL, NULL, nullptr);
//  invisibleClose->setAnchorPoint(Vec2::ANCHOR_BOTTOM_LEFT);
//  invisibleClose->setContentSize( visibleSize );
//  invisibleClose->setPosition(origin);
//  lock_menu->addChild(invisibleClose ); 
}

void PopupNode::SetupUI()
{
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();
    //////////////////////////////////////////////////////////////////////////
    auto cover = Sprite::create("Scene/PopUp/LoadingBackground.png");
    cover->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));
    this->addChild(cover, Z_BACKGROUND);
}

void PopupNode::BlockPassingTouch()
{
    auto listener = EventListenerTouchOneByOne::create();
    listener->setSwallowTouches(true);
    listener->onTouchBegan = [](Touch* touch, Event* event){
        if(event->getCurrentTarget()->isVisible() == false )
            return false;
        return true;
    };
    _eventDispatcher->addEventListenerWithSceneGraphPriority(listener, this);
}

void PopupNode::ClosePopup()
{
    this->removeFromParentAndCleanup(false);
}

You can create a new Layer with an box and an CCMenu with one CCMenuItem. The CCMenuItem will be your OK Button where you will set your callback method.

Something like...

CCSprite *box = [CCSprite spriteWithFile:@"box.png"];

box.position = ccp(screen.width/2,screen.height/2);

[self addChild:box];

CCMenuItemImage *okButton = [CCMenuItemImage itemFromNormalImage:@"yes.png" selectedImage:@"ok_button.png" target:self selector:@selector(okMethod)];

CCMenu *menu = [CCMenu menuWithItems:okButton,nil];

menu.position = ccp(box.boundingBox.size.width/2,box.boundingBox.size.height/2);

[box addChild:menu];

Hope it helps, :)