onEnterTransitionDidFinish()的用途

void BackgroundMove::onEnterTransitionDidFinish()//进入之后自动滑动，所以在调用时直接添加，不用调用方法。
{
	Layer::onEnterTransitionDidFinish();
	this->schedule(SEL_SCHEDULE(&BackgroundMove::move), 0.01f);
}

void BackgroundMove::move(float dt)
{
	Vec2 origin = Director::getInstance()->getVisibleOrigin();

	m_background1->setPositionY(m_background1->getPositionY() - OFFSET);
	m_background2->setPositionY(m_background1->getPositionY() + m_background1->getContentSize().height);
	if (m_background2->getPositionY() <= origin.y)
		m_background1->setPositionY(0);

	m_background3->setPositionY(m_background3->getPositionY() + OFFSET);
	m_background4->setPositionY(m_background3->getPositionY() - m_background3->getContentSize().height);
	if (m_background4->getPositionY() >= origin.y)
		m_background3->setPositionY(0);

}