CCScrollView 和 CCLabelTTF 组成CCScrollLabel

//
//  XJScrollLabel.h
//
//  Created by jason on 13-1-30.
//

#ifndef __COG__XJScrollLabel__
#define __COG__XJScrollLabel__

#include <iostream>
#include "cocos2d.h"
#include "cocos-ext.h"

USING_NS_CC;
USING_NS_CC_EXT;


#define POINTER_OPERATION( pointer, operation ) \
do\
{\
if( pointer )\
{\
operation;\
}\
}while( 0 )

//the anchor point of XJScrollLabel is the left-bottom corner.
class XJScrollLabel : public CCNode, public CCScrollViewDelegate
{
public://static functions
	static XJScrollLabel* create( const char* pszText, const char *fontName, float fontSize, CCTextAlignment hAlignment, CCSize ScrollViewSize );
	
public:
	XJScrollLabel();
	~XJScrollLabel();
	bool init( const char* pszText, const char *fontName, float fontSize, CCTextAlignment hAlignment, CCSize& ScrollViewSize );
	
	void setTextColor(const ccColor3B& color3)
	{ POINTER_OPERATION( m_pLabel, m_pLabel->setColor( color3 ) ); }
	
public://scroll view delegate
	virtual void scrollViewDidScroll(CCScrollView* view){}
    virtual void scrollViewDidZoom(CCScrollView* view){}
	
private:
	CCScrollView* m_pScrollView;
	CCLabelTTF* m_pLabel;
};

#endif /* defined(__COG__CGScrollLabel__) */

//
//  XJScrollLabel.cpp
//
//  Created by jason on 13-1-30.
//

#include "XJScrollLabel.h"

XJScrollLabel* XJScrollLabel::create(const char *pszText, const char *fontName, float fontSize, CCTextAlignment hAlignment, cocos2d::CCSize ScrollViewSize)
{
	XJScrollLabel* pScrollLabel = new XJScrollLabel;
	if( pScrollLabel && pScrollLabel->init( pszText, fontName, fontSize, hAlignment, ScrollViewSize ) )
	{
		pScrollLabel->autorelease();
		return pScrollLabel;
	}
	else
	{
		CC_SAFE_DELETE( pScrollLabel );
		return NULL;
	}
}

XJScrollLabel::XJScrollLabel() :
m_pScrollView( NULL ),
m_pLabel( NULL )
{
	
}

XJScrollLabel::~XJScrollLabel()
{
	CC_SAFE_RELEASE_NULL( m_pLabel );
	CC_SAFE_RELEASE_NULL( m_pScrollView );
}

bool XJScrollLabel::init(const char *pszText, const char *fontName, float fontSize, CCTextAlignment hAlignment, cocos2d::CCSize& ScrollViewSize)
{
	//object has been initialized.
	if( m_pScrollView || m_pLabel )
	{
		return false;
	}
	
	//constraint the label's width, but not height.
	m_pLabel = CCLabelTTF::create( pszText, fontName, fontSize, CCSizeMake( ScrollViewSize.width, 0 ), hAlignment );
	m_pLabel->retain();
	
	//get the texture size
	CCSize TextSize = m_pLabel->getTexture()->getContentSize();
	
	//we have to invoke CCScrollView::create( ScrollViewSize ) instead of 
	//CCScrollView::create( ScrollViewSize, m_pLabel ) to let the CCScrollView
	//create a default container for you.
	
	//It's because that the label may smaller than the view of
	//CCScrollView. If that is the condition, the label will be positioned
	//at the bottom of the View by CCScrollView. 
	
	//Even though you can set the label at the top, but the behavior of
	//ScrollView always try to reposition it. So we must ensure the container
	//is larger than the View of CCScrollView.
	m_pScrollView = CCScrollView::create( ScrollViewSize );
	m_pScrollView->retain();
	m_pScrollView->setDelegate( this );
	m_pScrollView->setDirection( kCCScrollViewDirectionVertical );
	
	//set the container size.
	//So we must ensure the conainer is larger than the View of CCScrollView.
	if( TextSize.height > ScrollViewSize.height )
	{
		m_pScrollView->setContentSize( TextSize );
		//make the left-top corner of container coincide with View's
		m_pScrollView->setContentOffset( ccp( 0, ScrollViewSize.height - TextSize.height ) );
	}
	else
	{
		m_pScrollView->setContentSize( ScrollViewSize );
	}
	
	//put the label at the top of the container.
	m_pScrollView->addChild( m_pLabel );
	m_pLabel->ignoreAnchorPointForPosition( false );
	m_pLabel->setAnchorPoint( ccp( 0, 1 ) );
	m_pLabel->setPosition( ccp( 0, m_pScrollView->getContentSize().height ) );
	

	addChild( m_pScrollView );
	return true;
}