在一个继承自cocos2d Sprite类的pawn类中，我在它的update函数中使用了this-＆gt; getBoundingBox（）。这导致“读取位置的访问冲突”错误。然后，我将“this”与“GAME :: PLAYER”交换，这是一个引用播放器的命名空间中的变量，并且它起作用。当GAME :: PLAYER-＆gt; getBoundingBox（）完美运行时，为什么this-＆gt; getBoundingBox（）会导致错误？它们不应该是同一个东西吗？请注意，“这 - ＆gt;”适用于任何其他函数但getBoundingBox。这是我做错的事吗？我对C ++不太好。
这是pawn.h
#include <cocos2d.h>
#ifndef PLAYER_CONTROLLER
#define PLAYER_CONTROLLER GAME::PLAYER
class pawn : public cocos2d::Sprite {
public:
pawn();
~pawn();
static pawn* create();
static pawn* create(bool default_moving);
bool moving;
bool right;
int speed;
cocos2d::Rect getBounds();
void step();
void initOptions();
void update(float dt) override;
void move(cocos2d::Vec2 vec);
void moveX(int x);
void moveY(int y);
virtual bool touchBegan(cocos2d::Touch*, cocos2d::Event*);
virtual void touchEnded(cocos2d::Touch*, cocos2d::Event*);
};
namespace GAME {
static pawn* PLAYER;
};
#endif
这是pawn.cpp
#include "player.h"
#include <cocos2d.h>
pawn::pawn() {
}
pawn::~pawn() {
}
bool pawn::touchBegan(cocos2d::Touch* touch, cocos2d::Event* event) {
this->move(cocos2d::Vec2(5, 0));
this->moving = false;
return true;
}
void pawn::touchEnded(cocos2d::Touch* touch, cocos2d::Event* event) {
this->moving = true;
}
void pawn::step() {
if (this->moving) {
if (this->right) {
this->move(cocos2d::Vec2(this->speed, 0));
}
else {
this->move(cocos2d::Vec2(-this->speed, 0));
}
if (this->getPositionX() < 0) {
this->right = true;
CCLOG("Going right V4");
}
else {
if (this->getPositionX() + this->getContentSize().width > cocos2d::Director::getInstance()->getWinSizeInPixels().width + cocos2d::Director::getInstance()->getVisibleOrigin().x){
this->right = false;
CCLOG("Going left V4");
}
}
}
}
void pawn::move(cocos2d::Vec2 vec) {
PLAYER_CONTROLLER->setPosition(cocos2d::Vec2(PLAYER_CONTROLLER->getPositionX() + vec.x, PLAYER_CONTROLLER->getPositionY() + vec.y));
}
void pawn::moveX(int x) {
}
void pawn::moveY(int y) {
}
void pawn::update(float dt) {
//cocos2d::Rect act = this->getBoundingBox();
this->getPosition();
this->step();
}
cocos2d::Rect pawn::getBounds() {
if (!PLAYER_CONTROLLER) {
CCLOG("Is this the problem?");
}
return PLAYER_CONTROLLER->getBoundingBox();
}
pawn* pawn::create() {
auto character = new pawn();
character->moving = true;
character->right = false;
character->speed = 5;
character->setPositionY(50);
if (PLAYER_CONTROLLER == NULL) {
CCLOG("There is no player, yet.");
CCLOG("Adding player");
PLAYER_CONTROLLER = character;
}
else {
CCLOG("There's already a player");
return NULL;
}
//character->setPositionX(40);
if (character->initWithFile("Base.jpg")){
return character;
}
CC_SAFE_DELETE(character);
return NULL;
}
pawn* pawn::create(bool default_moving) {
pawn* character = new pawn();
character->moving = default_moving;
character->setPositionX(40);
if (character->initWithFile("Base.jpg")){
return character;
}
CC_SAFE_DELETE(character);
return NULL;
}
是否因为我从另一个类调用pawn方法？我使用Collider类来调用pawn中的函数
Collider.cpp
#include "Collider.h"
#include "player.h"
Collider::Collider() : CollideMode(OVERLAP) {
}
Collider::~Collider() {
}
Collider* Collider::create() {
Collider* col = new Collider;
if (col->initWithFile("Base.jpg")){
col->setAnchorPoint(cocos2d::Vec2(0, 0));
col->setContentSize(cocos2d::Size(100, 100));
return col;
}
CC_SAFE_DELETE(col);
return NULL;
}
void Collider::collision(cocos2d::Vec2 intersect) {
CCLOG("IT IS COLLIDING");
if (intersect.x < intersect.y) {
PLAYER_CONTROLLER->move(cocos2d::Vec2(-intersect.x, 0));
CCLOG("X");
}
else if (intersect.x > intersect.y) {
PLAYER_CONTROLLER->move(cocos2d::Vec2(0, -intersect.y));
CCLOG("Y");
}
}
void Collider::update(float dt) {
//cocos2d::Rect col = this->getBoundingBox();
auto act = PLAYER_CONTROLLER->getBounds();
if (PLAYER_CONTROLLER) {
if (!PLAYER_CONTROLLER) {
CCLOG("There is no player?");
}
}
else {
CCLOG("Not colliding");
}
}
答案 0 :(得分：0)
我this->getBoundingBox()函数内update(float dt)似乎没有任何问题。
我创建了小测试：
在.h文件中的声明
class MySprite: public Sprite {
public:
bool init() override;
void update(float) override;
CREATE_FUNC(MySprite);
};
现在.cpp文件
bool MySprite::init(){
if(!Sprite::init())
return false;
scheduleUpdate();
return true;
}
void MySprite::update(float dt){
auto rect=this->getBoundingBox();
CCLOG("Inside Update method of MySprite Bounding rect Width %f & Height %f",rect.size.width,rect.size.height);
}
然后我创建了一个MySprite的自动释放对象并添加到父级。
auto mysprite=MySprite::create();
mysprite->setContentSize(Size(10,10));
addChild(mysprite);
在输出控制台上运行，预期结果。
答案 1 :(得分：0)
我看到了我的错误。事实上我每次都包含pawn.h时重新定义名称空间“GAME”和它的变量“GAME :: PLAYER”，我调用pawn函数的其他源文件不知道GAME :: PLAYER或者PLAYER_CONTROLLER（只是GAME :: PLAYER的一个宏），因为我只在pawn.cpp中定义了PLAYER_CONTROLLER。这就是为什么当你在另一个文件中调用PLAYER_CONTROLLER-＆gt; method（）时，它将NULL作为“this”传递，以及为什么PLAYER_CONTROLLER指的是另一个PLAYER_CONTROLLER而不是传入的“this”。
我通过使用extern关键字解决了这个问题，该关键字使变量在所有文件之间全局化，这是我的初衷。
pawn.h
#include <cocos2d.h>
#ifndef PLAYER_CONTROLLER
#define PLAYER_CONTROLLER GAME::PLAYER
#define INITIALIZE_PLAYER pawn* GAME::PLAYER = NULL
class pawn : public cocos2d::Sprite {
public:
pawn();
~pawn();
static pawn* create();
static pawn* getController();
static pawn* create(bool default_moving);
bool moving;
bool right;
int speed;
cocos2d::Rect getBounds();
void step();
void initOptions();
void update(float dt) override;
void move(cocos2d::Vec2 vec);
void moveX(int x);
void moveY(int y);
virtual bool touchBegan(cocos2d::Touch*, cocos2d::Event*);
virtual void touchEnded(cocos2d::Touch*, cocos2d::Event*);
};
namespace GAME {
extern pawn* PLAYER;
};
#endif
这就是为什么我说我不擅长C ++。