Cocos2d-x 3.2 学习笔记（九）EventDispatcher事件分发机制

EventDispatcher事件分发机制先创建事件，注册到事件管理中心_eventDispatcher，通过发布事件得到响应进行回调，完成事件流。

有五种不同的事件机制：
EventListenerTouch 响应触控事件
EventListenerKeyboard 响应键盘事件
EventListenerAcceleration 响应加速器事件
EventListenMouse 响应鼠标事件
EventListenerCustom 响应自定义的事件

优先权：

　　1.优先级越低，越先响应事件

　　2.如果优先级相同，则上层的（z轴）先接收触摸事件。

事件监听器的优先级：

　　1.addEventListenerWithSceneGraphPriority 的事件监听器优先级是0，而且在 addEventListenerWithFixedPriority 中的事件监听器的优先级不可以设置为 0，因为这个是保留给 SceneGraphPriority 使用的。

　　2.另外，有一点非常重要，FixedPriority listener添加完之后需要手动remove，而SceneGraphPriority listener是跟node绑定的，在node的析构函数中会被移除。移除方法：dispatcher->removeEventListener(listener);

事件管理单例获取：
　　_eventDispatcher是Node的属性，通过它管理当前节点（场景、层、精灵等）的所有事件的分发。但它本身是一个单例模式值的引用，在Node的构造函数中，通过Director::getInstance()->getEventDispatcher(); 获取，有了这个属性，就能方便的处理事件。

触摸事件：

　　

void EventDispatcherTest::funEventTouch(Sprite* sprite)
{
    this->_eventDispatcher->removeAllEventListeners();
    
    auto listener = EventListenerTouchOneByOne::create();
    listener->onTouchBegan = CC_CALLBACK_2(EventDispatcherTest::onTouchBeganss,this);
    listener->onTouchMoved = CC_CALLBACK_2(EventDispatcherTest::onTouchMovedss,this);
    listener->onTouchEnded = CC_CALLBACK_2(EventDispatcherTest::onTouchEndedss,this);
    listener->onTouchCancelled = CC_CALLBACK_2(EventDispatcherTest::onTouchCancelledss,this);
    listener->setSwallowTouches(true);//是否向下传递
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,sprite);
}

bool EventDispatcherTest::onTouchBeganss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());

    Vec2 locationInNode = target->convertToNodeSpace(touch->getLocation());
    Size s = target->getContentSize();
    Rect rect = Rect(0, 0, s.width, s.height);
　　//判断触摸区域是否在目标上
    if (rect.containsPoint(locationInNode))
    {
        label->setString("onTouchBegan......");
        target->setOpacity(180);
        return true;
    }
    return false;
}
void EventDispatcherTest::onTouchMovedss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());
    target->setPosition(target->getPosition() + touch->getDelta());
    label->setString("onTouchMoved......");
}
void EventDispatcherTest::onTouchEndedss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());
    target->setOpacity(255);
    label->setString("onTouchEnded......");
}
void EventDispatcherTest::onTouchCancelledss(Touch* touch,Event* ev)
{
    label->setString("onTouchCancelled......");
}

键盘事件

void EventDispatcherTest::funEventKeyboard()
{
    this->_eventDispatcher->removeAllEventListeners();

    auto listener = EventListenerKeyboard::create();
    listener->onKeyPressed = CC_CALLBACK_2(EventDispatcherTest::onKeyPressedss,this);
    listener->onKeyReleased = CC_CALLBACK_2(EventDispatcherTest::onKeyReleasedss,this);
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,this);
}

void EventDispatcherTest::onKeyPressedss(EventKeyboard::KeyCode keycode,Event* ev)
{
    char txt[100] = {};
    sprintf_s(txt,"key %d is Pressed!",(int)keycode);
    label->setString(txt);
}

void EventDispatcherTest::onKeyReleasedss(EventKeyboard::KeyCode keycode,Event* ev)
{
    label->setString("key is Released!");
}

鼠标事件

void EventDispatcherTest::funEventMouse(Sprite* sprite)
{
    this->_eventDispatcher->removeAllEventListeners();

    auto listener = EventListenerMouse::create();
    listener->onMouseDown = CC_CALLBACK_1(EventDispatcherTest::onMouseDownss,this);
    listener->onMouseMove = CC_CALLBACK_1(EventDispatcherTest::onMouseMovess,this);
    listener->onMouseUp = CC_CALLBACK_1(EventDispatcherTest::onMouseUpss,this);
    listener->onMouseScroll = CC_CALLBACK_1(EventDispatcherTest::onMouseScrollss,this);
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,sprite);
}

void EventDispatcherTest::onMouseDownss(Event* ev)
{
    label->setString("onMouseDown!");
}
void EventDispatcherTest::onMouseMovess(Event* ev)
{
    label->setString("onMouseMove!");
}
void EventDispatcherTest::onMouseUpss(Event* ev)
{
    label->setString("onMouseUp!");
}
void EventDispatcherTest::onMouseScrollss(Event* ev)
{
    label->setString("onMouseScroll!");
}

自定义事件

　　

//自定義事件
     funEventCustom();
     //2秒後派發一次自定義事件，測試
     scheduleOnce(schedule_selector(EventDispatcherTest::dispatcherCustomEvents),2.0f);

void EventDispatcherTest::funEventCustom()
{
    auto listener = EventListenerCustom::create("custom_event_1",CC_CALLBACK_1(EventDispatcherTest::onEventCustom,this));
    this->_eventDispatcher->addEventListenerWithFixedPriority(listener,1);//添加到事件分發器
}

void EventDispatcherTest::dispatcherCustomEvents(float at)
{
    //派發事件custom_event_1  事件內容為字符串custom event test!
    this->_eventDispatcher->dispatchCustomEvent("custom_event_1","custom event test!");
}

void EventDispatcherTest::onEventCustom(EventCustom* event)
{
    auto data = static_cast<char*>(event->getUserData());
    label->setString(data);
}

加速器事件

　　除了触摸，移动设备上一个很重要的输入源是设备的方向，因此大多数设备都配备了加速计，用于测量设备静止或匀速运动时所受到的重力方向。

重力感应来自移动设备的加速计，通常支持X,Y和Z三个方向的加速度感应，所以又称为三向加速计。在实际应用中，可以根据3个方向的力度大小来计算手机倾斜的角度或方向。

加速计监听器EventListenerAcceleration，其静态create方法中有个Acceleration的参数。Acceleration是一个类，包含了加速计获得的3个方向的加速度。

void EventDispatcherTest::funEventAcceleration()
{
    //啟動硬件設備
    Device::setAccelerometerEnabled(true); 

    auto listener = EventListenerAcceleration::create(CC_CALLBACK_2(EventDispatcherTest::onAcceleration,this));
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,this);
}

void EventDispatcherTest::onAcceleration(Acceleration* acc,Event* event)
{
    char str[100]={};
    sprintf_s(str,"x:%2d,y:%2d,z:%2d,timestamp:%2d",acc->x,acc->y,acc->z,acc->timestamp);
    log(str);
}

示例代码

#ifndef __EventDispatcherTest__
#define __EventDispatcherTest__

#include "cocos2d.h"

USING_NS_CC;

class EventDispatcherTest : public Layer
{
public:
    CREATE_FUNC(EventDispatcherTest);
    virtual bool init();
    static Scene* createScene();
    LabelTTF* label;
    void funEventTouch(Sprite* sprite);
    void funEventKeyboard();
    void funEventMouse(Sprite* sprite);
    void funEventCustom();
    void funEventAcceleration();

    bool onTouchBeganss(Touch* touch,Event* ev);
    void onTouchMovedss(Touch* touch,Event* ev);
    void onTouchEndedss(Touch* touch,Event* ev);
    void onTouchCancelledss(Touch* touch,Event* ev);

    void onKeyPressedss(EventKeyboard::KeyCode keycode,Event* ev);
    void onKeyReleasedss(EventKeyboard::KeyCode keycode,Event* ev);

    void onMouseDownss(Event* ev);
    void onMouseMovess(Event* ev);
    void onMouseUpss(Event* ev);
    void onMouseScrollss(Event* ev);

    void dispatcherCustomEvents(float at);
    void onEventCustom(EventCustom* event);


    void onAcceleration(Acceleration* acc,Event* event);
};

#endif

#include "EventDispatcherTest.h"
Scene* EventDispatcherTest::createScene()
{
    auto scene = Scene::create();
    auto layer = EventDispatcherTest::create();
    scene->addChild(layer);
    return scene;
}

bool EventDispatcherTest::init()
{

    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();
    label = LabelTTF::create("Hello World", "Arial", 24);
    label->setPosition(Vec2(origin.x + visibleSize.width/2,
        origin.y + visibleSize.height - label->getContentSize().height));
    this->addChild(label, 100);

    auto sprite = Sprite::create("MagentaSquare.png",Rect(0,0,100,100));
    sprite->setPosition(visibleSize/2);
    this->addChild(sprite);

    //funEventTouch(sprite); //觸摸事件
    //funEventKeyboard();    //鍵盤事件
    //funEventMouse(sprite);//鼠標事件
    //funEventAcceleration();//加速器事件

    //自定義事件
     funEventCustom();
     //2秒後派發一次自定義事件，測試
     scheduleOnce(schedule_selector(EventDispatcherTest::dispatcherCustomEvents),2.0f);
    return true;
}

void EventDispatcherTest::funEventTouch(Sprite* sprite)
{
    this->_eventDispatcher->removeAllEventListeners();
    
    auto listener = EventListenerTouchOneByOne::create();
    listener->onTouchBegan = CC_CALLBACK_2(EventDispatcherTest::onTouchBeganss,this);
    listener->onTouchMoved = CC_CALLBACK_2(EventDispatcherTest::onTouchMovedss,this);
    listener->onTouchEnded = CC_CALLBACK_2(EventDispatcherTest::onTouchEndedss,this);
    listener->onTouchCancelled = CC_CALLBACK_2(EventDispatcherTest::onTouchCancelledss,this);
    listener->setSwallowTouches(true);//是否向下传递
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,sprite);
}

bool EventDispatcherTest::onTouchBeganss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());

    Vec2 locationInNode = target->convertToNodeSpace(touch->getLocation());
    Size s = target->getContentSize();
    Rect rect = Rect(0, 0, s.width, s.height);

    if (rect.containsPoint(locationInNode))
    {
        label->setString("onTouchBegan......");
        target->setOpacity(180);
        return true;
    }
    return false;
}
void EventDispatcherTest::onTouchMovedss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());
    target->setPosition(target->getPosition() + touch->getDelta());
    label->setString("onTouchMoved......");
}
void EventDispatcherTest::onTouchEndedss(Touch* touch,Event* ev)
{
    auto target = static_cast<Sprite*>(ev->getCurrentTarget());
    target->setOpacity(255);
    label->setString("onTouchEnded......");
}
void EventDispatcherTest::onTouchCancelledss(Touch* touch,Event* ev)
{
    label->setString("onTouchCancelled......");
}


void EventDispatcherTest::funEventKeyboard()
{
    this->_eventDispatcher->removeAllEventListeners();

    auto listener = EventListenerKeyboard::create();
    listener->onKeyPressed = CC_CALLBACK_2(EventDispatcherTest::onKeyPressedss,this);
    listener->onKeyReleased = CC_CALLBACK_2(EventDispatcherTest::onKeyReleasedss,this);
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,this);
}

void EventDispatcherTest::onKeyPressedss(EventKeyboard::KeyCode keycode,Event* ev)
{
    char txt[100] = {};
    sprintf_s(txt,"key %d is Pressed!",(int)keycode);
    label->setString(txt);
}

void EventDispatcherTest::onKeyReleasedss(EventKeyboard::KeyCode keycode,Event* ev)
{
    label->setString("key is Released!");
}

void EventDispatcherTest::funEventMouse(Sprite* sprite)
{
    this->_eventDispatcher->removeAllEventListeners();

    auto listener = EventListenerMouse::create();
    listener->onMouseDown = CC_CALLBACK_1(EventDispatcherTest::onMouseDownss,this);
    listener->onMouseMove = CC_CALLBACK_1(EventDispatcherTest::onMouseMovess,this);
    listener->onMouseUp = CC_CALLBACK_1(EventDispatcherTest::onMouseUpss,this);
    listener->onMouseScroll = CC_CALLBACK_1(EventDispatcherTest::onMouseScrollss,this);
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,sprite);
}

void EventDispatcherTest::onMouseDownss(Event* ev)
{
    label->setString("onMouseDown!");
}
void EventDispatcherTest::onMouseMovess(Event* ev)
{
    label->setString("onMouseMove!");
}
void EventDispatcherTest::onMouseUpss(Event* ev)
{
    label->setString("onMouseUp!");
}
void EventDispatcherTest::onMouseScrollss(Event* ev)
{
    label->setString("onMouseScroll!");
}

void EventDispatcherTest::funEventCustom()
{
    auto listener = EventListenerCustom::create("custom_event_1",CC_CALLBACK_1(EventDispatcherTest::onEventCustom,this));
    this->_eventDispatcher->addEventListenerWithFixedPriority(listener,1);//添加到事件分發器
}

void EventDispatcherTest::dispatcherCustomEvents(float at)
{
    //派發事件custom_event_1  事件內容為字符串custom event test!
    this->_eventDispatcher->dispatchCustomEvent("custom_event_1","custom event test!");
}

void EventDispatcherTest::onEventCustom(EventCustom* event)
{
    auto data = static_cast<char*>(event->getUserData());
    label->setString(data);
}

void EventDispatcherTest::funEventAcceleration()
{
    //啟動硬件設備
    Device::setAccelerometerEnabled(true); 

    auto listener = EventListenerAcceleration::create(CC_CALLBACK_2(EventDispatcherTest::onAcceleration,this));
    this->_eventDispatcher->addEventListenerWithSceneGraphPriority(listener,this);
}

void EventDispatcherTest::onAcceleration(Acceleration* acc,Event* event)
{
    char str[100]={};
    sprintf_s(str,"x:%2d,y:%2d,z:%2d,timestamp:%2d",acc->x,acc->y,acc->z,acc->timestamp);
    log(str);
}