Cocos2d-x 3.2 學習筆記（九）EventDispatcher事件分發機制

EventDispatcher事件分發機制先建立事件，註冊到事件管理中心_eventDispatcher，經過發佈事件獲得響應進行回調，完成事件流。

有五種不一樣的事件機制：
EventListenerTouch 響應觸控事件
EventListenerKeyboard 響應鍵盤事件
EventListenerAcceleration 響應加速器事件
EventListenMouse 響應鼠標事件
EventListenerCustom 響應自定義的事件

優先權：

　　1.優先級越低，越先響應事件

　　2.若是優先級相同，則上層的（z軸）先接收觸摸事件。

事件監聽器的優先級：

　　1.addEventListenerWithSceneGraphPriority 的事件監聽器優先級是0，並且在 addEventListenerWithFixedPriority 中的事件監聽器的優先級不能夠設置爲 0，由於這個是保留給 SceneGraphPriority 使用的。

　　2.另外，有一點很是重要，FixedPriority listener添加完以後須要手動remove，而SceneGraphPriority listener是跟node綁定的，在node的析構函數中會被移除。移除方法：dispatcher->removeEventListener(listener);

事件管理單例獲取：
　　_eventDispatcher是Node的屬性，經過它管理當前節點（場景、層、精靈等）的全部事件的分發。但它自己是一個單例模式值的引用，在Node的構造函數中，經過Director::getInstance()->getEventDispatcher(); 獲取，有了這個屬性，就能方便的處理事件。

 

觸摸事件：

　　

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);//是否向下傳遞
    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); 　　//判斷觸摸區域是否在目標上 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......"); }

鍵盤事件

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!"); }

鼠標事件

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!"); }

自定義事件

　　

//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

　　除了觸摸，移動設備上一個很重要的輸入源是設備的方向，所以大多數設備都配備了加速計，用於測量設備靜止或勻速運動時所受到的重力方向。

重力感應來自移動設備的加速計，一般支持X,Y和Z三個方向的加速度感應，因此又稱爲三向加速計。在實際應用中，能夠根據3個方向的力度大小來計算手機傾斜的角度或方向。

加速計監聽器EventListenerAcceleration，其靜態create方法中有個Acceleration的參數。Acceleration是一個類，包含了加速計得到的3個方向的加速度。

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); }

 

 

示例代碼

#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

EventDispatcherTest.h

#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);//是否向下傳遞
    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);
}

EventDispatcherTest.cpp