iphone - 使用 cocos2d 处理 CCSprite 触摸的最佳实践

Question

大家好。我刚刚开始研究 cocos2d 库。我听说，如果您习惯使用 ActionScript 进行编程，那么这是一个很容易上手的库，并且我发现很多概念确实相似。

我开始查看示例项目(链接的示例游戏here特别有帮助)，我发现触摸处理通常不是在CCSprite中完成的。相反，实例化 CCSprite 的 CCLayer 对触摸事件使用react，并迭代它创建的 Sprite 以检测哪个 CCSprite 被触摸(如果有)。

我希望 CCSprite 能够处理它们自己是否被触摸，并调用 up 来通知它已被触摸(如果需要)。/tests/TouchesTest 下的 Paddle 类就是这样做的 - 它自己处理触摸。

所以，我的问题是:什么是最佳实践？在中心位置处理触摸并遍历子级以查看触摸的内容是否更好？或者每个 child 应该处理自己的触摸事件？还是说没关系？

我希望每个 child 处理自己的触摸事件，但我想遵循这方面的最佳实践(如果存在)。谢谢!

Answer 1

我认为这是一个偏好问题，但我喜欢让 Sprite 检测它是否被子类化 CCSprite 所触及。我在 CCSprite 子类中创建了一个 getter 方法，用于从子类中检索状态变量，然后主程序可以采取相应的操作。

这是我的 CCSprite 子类“spuButton”的示例头文件:

    #import "cocos2d.h"

    typedef enum tagButtonState {
        kButtonStatePressed,
        kButtonStateNotPressed
    } ButtonState;

    typedef enum tagButtonStatus {
        kButtonStatusEnabled,
        kButtonStatusDisabled
    } ButtonStatus;

    @interface spuButton : CCSprite <CCTargetedTouchDelegate> {
    @private
        ButtonState state;
        CCTexture2D *buttonNormal;
        CCTexture2D *buttonLit;
        ButtonStatus buttonStatus;

    }

    @property(nonatomic, readonly) CGRect rect;

    + (id)spuButtonWithTexture:(CCTexture2D *)normalTexture;

    - (void)setNormalTexture:(CCTexture2D *)normalTexture;
    - (void)setLitTexture:(CCTexture2D *)litTexture;
    - (BOOL)isPressed;
    - (BOOL)isNotPressed;

    @end

这是 .m 文件的示例:

    #import "spuButton.h"
    #import "cocos2d.h"

    @implementation spuButton

    - (CGRect)rect
    {
        CGSize s = [self.texture contentSize];
        return CGRectMake(-s.width / 2, -s.height / 2, s.width, s.height);
    }

    + (id)spuButtonWithTexture:(CCTexture2D *)normalTexture
    {
        return [[[self alloc] initWithTexture:normalTexture] autorelease];
    }

    - (void)setNormalTexture:(CCTexture2D *)normalTexture {
        buttonNormal = normalTexture;
    }
    - (void)setLitTexture:(CCTexture2D *)litTexture {
        buttonLit = litTexture;
    }

    - (BOOL)isPressed {
        if (state == kButtonStateNotPressed) return NO;
        if (state == kButtonStatePressed) return YES;
        return NO;
    }

    - (BOOL)isNotPressed {
        if (state == kButtonStateNotPressed) return YES;
        if (state == kButtonStatePressed) return NO;
        return YES;
    }

    - (id)initWithTexture:(CCTexture2D *)aTexture
    {
        if ((self = [super initWithTexture:aTexture]) ) {

            state = kButtonStateNotPressed;
        }

        return self;
    }

    - (void)onEnter
    {
        [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES];
        [super onEnter];
    }

    - (void)onExit
    {
        [[CCTouchDispatcher sharedDispatcher] removeDelegate:self];
        [super onExit];
    }   

    - (BOOL)containsTouchLocation:(UITouch *)touch
    {
        return CGRectContainsPoint(self.rect, [self convertTouchToNodeSpaceAR:touch]);
    }

    - (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event
    {
        if (state == kButtonStatePressed) return NO;
        if ( ![self containsTouchLocation:touch] ) return NO;
        if (buttonStatus == kButtonStatusDisabled) return NO;

        state = kButtonStatePressed;
        [self setTexture:buttonLit];

        return YES;
    }

    - (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event
    {
        // If it weren't for the TouchDispatcher, you would need to keep a reference
        // to the touch from touchBegan and check that the current touch is the same
        // as that one.
        // Actually, it would be even more complicated since in the Cocos dispatcher
        // you get NSSets instead of 1 UITouch, so you'd need to loop through the set
        // in each touchXXX method.

        if ([self containsTouchLocation:touch]) return;
        //if (buttonStatus == kButtonStatusDisabled) return NO;

        state = kButtonStateNotPressed;
        [self setTexture:buttonNormal];

    }

    - (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event
    {

        state = kButtonStateNotPressed;
        [self setTexture:buttonNormal];


    }

@end

希望这对您有所帮助，祝您编码愉快!

添加勾选方法和解释(针对下面斯蒂芬的问题):

为了检查按钮的状态，我有一个 tick: 方法，它基本上会触发每一帧并检查所有按钮的状态。

    -(void)tick:(ccTime)dt {

do my button checks here....

}

我通过调用 spuButton 类中的 isPressed 或 isNotPressed 函数来检查按钮的状态。

for (spuButton *aButton in _fourButtonsArray) {
     if ([aButton isNotPressed]) continue; //this button is not pressed
     .....otherwise record that it is pressed.....
}

然后我进行同样的检查，看看它是否已发布并做出相应的响应。我这样做是因为我希望能够对多个按钮按下组合使用react，而且我想在按下按钮时执行某些操作，然后在释放按钮时执行其他操作。我使用 ccTouchBegan 和 ccTouchEnded 来更改纹理( Sprite 图像)并相应地更改状态变量。