多平台响应键盘事件！（适用于Cocos2dx 3.0 alpha以上版本号）

Hello everyone! For a week I’ve been looking on how to make a keyboard work!

I managed to figure it out and I want to share my knowledge with you!

So, before we get started - this tutorial only works on Cocos2d-x 3.0alpha and later.

We will start by making two functions in the scene we want keyboard on.

They will be:

首先在须要键盘处理事件的场景中文件里加入例如以下两个函数。

OurScene.h:
void keyPressed(cocos2d::EventKeyboard::KeyCode keyCode, cocos2d::Event *event);
void keyReleased(cocos2d::EventKeyboard::KeyCode keyCode, cocos2d::Event *event);

OurScene.cpp:
void OurScene::keyPressed(cocos2d::EventKeyboard::KeyCode keyCode, cocos2d::Event *event)
{

}
void OurScene::keyReleased(cocos2d::EventKeyboard::KeyCode keyCode, cocos2d::Event *event)
{

}

These functions will be called when we press/release a key on the keyboard.

Next we need a listener to look for the keyboard we will create it like so (I did it in the init function)

当键盘按下时会调用上面这两的函数。

接下来在init()方法中加入例如以下代码来监听键盘事件。

auto keyboardListener = EventListenerKeyboard::create();
keyboardListener->onKeyPressed = CC_CALLBACK_2(OurScene::keyPressed, this);
keyboardListener->onKeyReleased = CC_CALLBACK_2(OurScene::keyReleased, this);
EventDispatcher::getInstance()->addEventListenerWithSceneGraphPriority(listener, this); // use if your version is below cocos2d-x 3.0alpha.1
// use this: Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(listener, this); if you are using cocos2d-x 3.0alpha.1 and later!

This code creates a keyboard listener and then setting what functions will be called when the key is pressed or released.

Now Our program can detect keyboard! Wait… How do I know what key is pressed? It is simple! Let me show you:

然后就能够在最上面的两个方法中加入keyCode的判定了。

//put this inside keyPressed or keyReleased
if (keyCode == EventKeyboard::KeyCode::KEY_W)
{
    CCLog("W key was pressed");
}

This piece of code will check what is the key-code of the key that was pressed. The list of key-codes is inside the EventKeyboard class. To use a keycode you just type:

EventKeyboard::KeyCode::KEY_**whatever key** - you will usually get a list of available keys to chose from.

Well, I think that’s it! Enjoy!

參考：http://www.cocos2d-x.org/forums/6/topics/39145