【cocos2dx开发技巧8】自定义控件－使自定义控件具有RGBA特性

转发，请保持地址：http://blog.csdn.net/stalendp/article/details/9948545

虽然CCNodeRGBA，CCLayerRGBA，sprite等提供颜色和透明度的设置，但有时候要自定义控件，要自己去实现那些功能。比如，我要扩充一个CCSpriteBatchNode，同时要要具有颜色和透明度的设置，这个时候就需要自己动手了。

其实为自己的控件添加RGBA特性并不是很难，只要继承CCRGBAProtocol，然后把CCNodeRGBA的实现方案贴到新加的类中就可以了。不过这样不便于代码的重用，所以我在改造代码的过程中使用了“适配器设计模式”。 这也是这片文章要介绍的一点。

贴上我的设配器类：MyRGBAProtocolAdapter

class MyRGBAProtocolAdapter: public CCRGBAProtocol {protected:GLubyte_displayedOpacity, _realOpacity;ccColor3B_displayedColor, _realColor;bool_cascadeOpacityEnabled, _cascadeColorEnabled;protected:virtual CCArray* getRGBAChildren() = 0;virtual CCNode* getRGBAParent() = 0;public:MyRGBAProtocolAdapter() :_cascadeColorEnabled(true),_cascadeOpacityEnabled(true),_displayedOpacity(255),_realOpacity(255),_displayedColor(ccc3(255, 255, 255)),_realColor(ccc3(255, 255, 255)) {}virtual void setColor(const ccColor3B& color) {_displayedColor = _realColor = color;if (_cascadeColorEnabled){ccColor3B parentColor = ccWHITE;CCRGBAProtocol *parent = dynamic_cast<CCRGBAProtocol*>(getRGBAParent());if (parent && parent->isCascadeColorEnabled()){parentColor = parent->getDisplayedColor();}updateDisplayedColor(parentColor);}}    virtual const ccColor3B& getColor(void) {return _realColor;}    virtual const ccColor3B& getDisplayedColor(void) {return _displayedColor;}    virtual GLubyte getDisplayedOpacity(void) {return _displayedOpacity;}    virtual GLubyte getOpacity(void) {return _realOpacity;}        virtual void setOpacity(GLubyte opacity) {_displayedOpacity = _realOpacity = opacity;if (_cascadeOpacityEnabled){GLubyte parentOpacity = 255;CCRGBAProtocol* pParent = dynamic_cast<CCRGBAProtocol*>(getRGBAParent());if (pParent && pParent->isCascadeOpacityEnabled()){parentOpacity = pParent->getDisplayedOpacity();}this->updateDisplayedOpacity(parentOpacity);}}    virtual void setOpacityModifyRGB(bool bValue) {}    virtual bool isOpacityModifyRGB(void) {return false;}    virtual bool isCascadeColorEnabled(void) {return _cascadeColorEnabled;}    virtual void setCascadeColorEnabled(bool cascadeColorEnabled) {_cascadeColorEnabled = cascadeColorEnabled;}        virtual void updateDisplayedColor(const ccColor3B& parentColor) {_displayedColor.r = _realColor.r * parentColor.r/255.0;_displayedColor.g = _realColor.g * parentColor.g/255.0;_displayedColor.b = _realColor.b * parentColor.b/255.0;if (_cascadeColorEnabled){CCObject *obj = NULL;CCARRAY_FOREACH(getRGBAChildren(), obj){CCRGBAProtocol *item = dynamic_cast<CCRGBAProtocol*>(obj);if (item){item->updateDisplayedColor(_displayedColor);}}}}        virtual bool isCascadeOpacityEnabled(void) {return _cascadeOpacityEnabled;}    virtual void setCascadeOpacityEnabled(bool cascadeOpacityEnabled) {_cascadeOpacityEnabled = cascadeOpacityEnabled;}    virtual void updateDisplayedOpacity(GLubyte parentOpacity) {_displayedOpacity = _realOpacity * parentOpacity/255.0;if (_cascadeOpacityEnabled){CCObject* pObj;CCARRAY_FOREACH(getRGBAChildren(), pObj){CCRGBAProtocol* item = dynamic_cast<CCRGBAProtocol*>(pObj);if (item){item->updateDisplayedOpacity(_displayedOpacity);}}}}};

注意到，其实MyRGBAProtocolAdapter类是一个抽象类，下面的两个方法是要被子类实现的：

virtual CCArray* getRGBAChildren() = 0;virtual CCNode* getRGBAParent() = 0;

虽然多继承不好，不过我这里还是使用了，下面是我的实现类：

/** 可以改变颜色和透明度的 Sprite batch Node **/#define BBB_AIM_DU 0.3 class BBBatch : public CCSpriteBatchNode, public MyRGBAProtocolAdapter { // 1)继承MyRGBAProtocolAdapterpublic:static BBBatch* create(const char* fileImage, unsigned int capacity) {BBBatch *batchNode = new BBBatch();if (batchNode && batchNode->initWithFile(fileImage, capacity)) {batchNode->autorelease();return batchNode;}CC_SAFE_DELETE(batchNode);return NULL;}void dark() {runAction(CCTintTo::create(BBB_AIM_DU, 150, 150, 150));runAction(CCFadeTo::create(BBB_AIM_DU, 255*0.6));}void normal() {runAction(CCTintTo::create(BBB_AIM_DU, 255, 255, 255));runAction(CCFadeTo::create(BBB_AIM_DU, 255));}//2）下面将实现两个抽象类// ========= MyRGBAProtocolAdapter begin ============ CCArray* getRGBAChildren() {return getChildren();}CCNode* getRGBAParent() {return getParent();}// ========= MyRGBAProtocolAdapter end ============};

这样就可以简单方便地把RGBA特性添加到自定义类中了。