Cocos2dx中在场景中弹出模态层时按钮的处理方法

在Cocos2dx游戏开发中经常会遇到在场景中弹出模态层，并在弹出层中添加按钮的情况。通常做法是在弹出层中添加一个背景颜色遮罩，然后在弹出层将触摸事件吞噬掉，使得在弹出层里处理触摸事件，判断触摸点是否在Button上，以此处理按钮事件。但是这样会出现按钮的显示不正常的问题，即按钮在点击之后会显示禁用的效果，解决防范是创建按钮的时候传入三个图片参数，最后两个参数是按钮点击和禁用时的图片，将他们设置为一样就行了。下面贴出具体代码，并对代码测试。

PopupLayer.h

#ifndef __POPUP_LAYER_H__
#define __POPUP_LAYER_H__

#include "cocos2d.h"
#include "ui/UIButton.h"

typedef enum tagButtonResult
{
	ButtonResult_OK = 0
} ButtonResult;

typedef std::function<void(cocos2d::Ref*,ButtonResult)> ButtonTouchedCallback;

class PopupLayer : public cocos2d::Layer
{
public:	
    // Here's a difference. Method 'init' in cocos2d-x returns bool,instead of returning 'id' in cocos2d-iphone
    virtual bool init() override;

	// 触摸事件
	virtual bool onTouchBegan(cocos2d::Touch *touch,cocos2d::Event *unused_event);
	virtual void onTouchMoved(cocos2d::Touch *touch,cocos2d::Event *unused_event);
	virtual void onTouchEnded(cocos2d::Touch *touch,cocos2d::Event *unused_event);
	virtual void onTouchCancelled(cocos2d::Touch *touch,cocos2d::Event *unused_event);

	// implement the "static create()" method manually
	CREATE_FUNC(PopupLayer);

public:
	//设置按钮回调函数
	void SetCallBackFunc(ButtonTouchedCallback callfunc);

private:
	//销毁layer并调用回调函数
	void DestroySelf(cocos2d::Ref* sender,ButtonResult result);

	//按钮回调函数
	void buttonCallback(cocos2d::Ref* sender,cocos2d::ui::Widget::TouchEventType event);

protected:
	cocos2d::EventListenerTouchOneByOne*	m_touchListener;	//触屏事件监听器
	ButtonTouchedCallback					m_callback;			//按钮回调函数
};

#endif // __POPUP_LAYER_H__

#include "PopupLayer.h"

USING_NS_CC;
using namespace ui;

const int TAG_BUTTON = 1;

// on "init" you need to initialize your instance
bool PopupLayer::init()
{
	if ( !Layer::init() )
	{
		return false;
	}

	m_callback = nullptr;

	//获取游戏区域
	Size visibleSize = Director::getInstance()->getVisibleSize();
	Vec2 origin = Director::getInstance()->getVisibleOrigin();

	//添加透明遮罩
	auto mask = LayerColor::create(Color4B(0,128),visibleSize.width,visibleSize.height);
	this->addChild(mask);

	//由于PopupLayer将触摸事件吞噬了，导致在判断点击事件的时候
	//使用了触摸点坐标是否在按钮是区域内的方式，这样Button的
	//setBright方法会使得点击按钮的时候显示Disable状态的图片，
	//因此将按钮的点击和禁用图片设置为一样，来解决这个问题。
	auto button = Button::create("test.png","test_effect.png","test_effect.png");
	button->setScale9Enabled(true);
	button->setTitleText("test button");
	button->setTitleFontSize(40);
	button->setContentSize(Size(visibleSize.width / 2,visibleSize.width / 4));
	button->setPosition(Vec2(origin.x + visibleSize.width / 2,origin.y + visibleSize.height / 2));
	button->addTouchEventListener(CC_CALLBACK_2(PopupLayer::buttonCallback,this));
	this->addChild(button,TAG_BUTTON);

	//触摸屏事件监听
	m_touchListener = EventListenerTouchOneByOne::create();
	m_touchListener->onTouchBegan = CC_CALLBACK_2(PopupLayer::onTouchBegan,this);
	m_touchListener->onTouchMoved = CC_CALLBACK_2(PopupLayer::onTouchMoved,this);
	m_touchListener->onTouchEnded = CC_CALLBACK_2(PopupLayer::onTouchEnded,this);
	m_touchListener->onTouchCancelled = CC_CALLBACK_2(PopupLayer::onTouchCancelled,this);
	m_touchListener->setSwallowTouches(true);
	this->getEventDispatcher()->addEventListenerWithFixedPriority(m_touchListener,-128);

	return true;
}

void PopupLayer::SetCallBackFunc(ButtonTouchedCallback callfunc)
{
	this->m_callback = callfunc;
}

//销毁layer并调用回调函数
void PopupLayer::DestroySelf(cocos2d::Ref* sender,ButtonResult result)
{
	this->getEventDispatcher()->removeEventListener(m_touchListener);
	m_callback(sender,result);
	this->removeFromParentAndCleanup(true);
}

// 触摸开始事件
bool PopupLayer::onTouchBegan(cocos2d::Touch *touch,cocos2d::Event *unused_event)
{
	auto button = (Button*)this->getChildByTag(TAG_BUTTON);
	if (button != nullptr)
	{
		const Size& size = button->getContentSize();
		const Vec2& pos = button->getPosition();
		Rect rect = Rect(pos.x - size.width / 2,pos.y - size.height / 2,size.width,size.height);
		auto touchLocation = touch->getLocation();

		if (rect.containsPoint(touchLocation))
		{
			button->setBright(false);
			button->onTouchBegan(touch,unused_event);
		}
	}
	return true;
}

// 触摸滑动
void PopupLayer::onTouchMoved(cocos2d::Touch *touch,size.height);
		auto touchLocation = touch->getLocation();

		if (rect.containsPoint(touchLocation))
		{
			button->onTouchMoved(touch,unused_event);
		}
		else
		{
			button->setBright(true);
		}
	}
}

// 触摸结束事件
void PopupLayer::onTouchEnded(cocos2d::Touch *touch,size.height);
		auto touchLocation = touch->getLocation();

		button->setBright(true);
		if (rect.containsPoint(touchLocation))
		{
			button->onTouchEnded(touch,unused_event);
		}
	}
}

// 触摸取消事件
void PopupLayer::onTouchCancelled(cocos2d::Touch *touch,size.height);
		auto touchLocation = touch->getLocation();

		button->setBright(true);
		if (rect.containsPoint(touchLocation))
		{
			button->onTouchCancelled(touch,unused_event);
		}
	}
}

void PopupLayer::buttonCallback(cocos2d::Ref* sender,cocos2d::ui::Widget::TouchEventType event)
{
	if (Widget::TouchEventType::CANCELED == event)
	{
		auto button = (Button*)sender;
		if (button != nullptr)
		{
			if (TAG_BUTTON == button->getTag())
			{
				DestroySelf(sender,ButtonResult::ButtonResult_OK);
			}
		}
	}
}

HelloWorldScene.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"
#include "PopupLayer.h"

class HelloWorld : public cocos2d::Scene
{
public:
    static cocos2d::Scene* createScene();

    virtual bool init();
    
    // a selector callback
    void menuCloseCallback(cocos2d::Ref* pSender);
    
    // implement the "static create()" method manually
    CREATE_FUNC(HelloWorld);

public:
	//弹出框按钮事件
	void buttonPopupCallback(cocos2d::Ref* sender,ButtonResult result);
};

#endif // __HELLOWORLD_SCENE_H__

HelloWorldScene.cpp

#include "HelloWorldScene.h"

USING_NS_CC;

Scene* HelloWorld::createScene()
{
    return HelloWorld::create();
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !Scene::init() )
    {
        return false;
    }
    
    auto visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();

    /////////////////////////////
    // 2. add a menu item with "X" image,which is clicked to quit the program
    //    you may modify it.

    // add a "close" icon to exit the progress. it's an autorelease object
    auto closeItem = MenuItemImage::create(
                                           "CloseNormal.png","CloseSelected.png",CC_CALLBACK_1(HelloWorld::menuCloseCallback,this));
    
    closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2,origin.y + closeItem->getContentSize().height/2));

    // create menu,it's an autorelease object
    auto menu = Menu::create(closeItem,NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu,1);

    /////////////////////////////
    // 3. add your codes below...

    // add a label shows "Hello World"
    // create and initialize a label
    
    auto label = Label::createWithTTF("Hello World","fonts/Marker Felt.ttf",24);
    
    // position the label on the center of the screen
    label->setPosition(Vec2(origin.x + visibleSize.width/2,origin.y + visibleSize.height - label->getContentSize().height));

    // add the label as a child to this layer
    this->addChild(label,1);

    // add "HelloWorld" splash screen"
    auto sprite = Sprite::create("HelloWorld.png");

    // position the sprite on the center of the screen
    sprite->setPosition(Vec2(visibleSize.width/2 + origin.x,visibleSize.height/2 + origin.y));

    // add the sprite as a child to this layer
    this->addChild(sprite,0);

	//添加弹出模态层
	auto login = PopupLayer::create();
	login->SetCallBackFunc(CC_CALLBACK_2(HelloWorld::buttonPopupCallback,this));
	this->addChild(login,10);
    
    return true;
}


void HelloWorld::menuCloseCallback(Ref* pSender)
{
    //Close the cocos2d-x game scene and quit the application
    Director::getInstance()->end();

    #if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
    
    /*To navigate back to native iOS screen(if present) without quitting the application,do not use Director::getInstance()->end() and exit(0) as given above,instead trigger a custom event created in RootViewController.mm as below*/
    
    //EventCustom customEndEvent("game_scene_close_event");
    //_eventDispatcher->dispatchEvent(&customEndEvent);
}

void HelloWorld::buttonPopupCallback(cocos2d::Ref* sender,ButtonResult result)
{
	switch (result)
	{
	case ButtonResult::ButtonResult_OK:
		Director::getInstance()->end();
		break;
	default:
		break;
	}
}

（编辑：李大同）

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