怎么监听了键盘事件不触发？？

Cocos2d-x
#1

auto listenerKeyboard = EventListenerKeyboard::create ( );
listenerKeyboard->onKeyReleased = CC_CALLBACK_2 ( MainScene::onKeyReleased , this );
_eventDispatcher->addEventListenerWithSceneGraphPriority ( listenerKeyboard , this );

void MainScene::onKeyReleased ( EventKeyboard::KeyCode keycode , Event* event )
{
if ( keycode == EventKeyboard::KeyCode::KEY_BACKSPACE )
{
log(“onKeyReleased”);
}
}

#2

_eventDispatcher->addEventListenerWithSceneGraphPriority ( listenerKeyboard , this );
改成：
Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(listenerKeyboard ,this);
试试