使用 cocos2d 处理对 CCSprite 的触摸的最佳实践

Question

大家好。我刚开始研究 cocos2d 库。我听说如果您习惯使用 ActionScript 进行编程，它是一个很容易进入的库，而且我发现很多概念确实相似。

我开始浏览示例项目（链接here 的示例游戏特别有用），我发现通常不会在 CCSprite 中处理触摸。相反，实例化 CCSprites 的 CCLayer 对触摸事件做出反应，并遍历它创建的 sprite 以检测哪个 CCSprite 被触摸（如果有的话）。

我希望 CCSprites 自己处理它们是否已被触摸，并调用 up 以通知它已被触摸（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项以查看触摸了什么会更好吗？还是每个孩子都应该处理自己的触摸事件？还是没关系？

我希望每个孩子都处理自己的触摸事件，但我想遵循这方面的最佳做法（如果存在）。谢谢！

Answer 1

我认为这是一个偏好问题，但我喜欢让精灵检测它是否被子类化 CCSprite 触及。我在我的 CCSprite 子类中创建了一个 getter 方法，该方法从子类中检索状态变量，然后主程序可以相应地采取行动。

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

以下是 .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！

增加打勾方法和解释（针对Stephan的问题如下）：

要检查按钮的状态，我有一个勾号：基本上触发每一帧并检查所有按钮状态的方法。

    -(void)tick:(ccTime)dt {

do my button checks here....

}

我通过调用我的 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.....
}

然后我做同样的检查，看看它是否已经被释放并做出相应的回应。我这样做是因为我希望能够对多个按钮按下组合做出反应，而且我想在它被按下时做一些事情，然后在它被释放时做其他事情。我使用 ccTouchBegan 和 ccTouchEnded 来更改纹理（精灵图像）并相应地更改状态变量。

Answer 2

只是添加到这个线程。 Mark 还提供了一个如何实例化 spuButton 的示例，这很有帮助：

Problem with cocos2d and orientation changes, textures are deformed

您还可以修改此示例以传递正常和亮起的按钮图像，如下所示：

+ (id)spuButtonWithTexture:(CCTexture2D *)normalTexture lit:(CCTexture2D *)litTexture

然后做同样的事情：

- (id)initWithTexture:(CCTexture2D *)normalTexture lit:(CCTexture2D *)litTexture

在此方法中，您可以设置两种纹理：

[self setNormalTexture:normalTexture];
[self setLitTexture:litTexture];

Answer 3

这是我的解决方案，基于 CCSprite 希望它对某人有用

这是受控对象（如播放器或其他东西）的协议：

@class AGSensitiveButton;

@protocol AGSensitiveButtonControlledObjectProtocol <NSObject>
@required
- (void)sensitiveButtonTouchDown:(AGSensitiveButton *)sButton;
- (void)sensitiveButtonTouchUp:(AGSensitiveButton *)sButton;
@optional
- (void)sensitiveTouchButtonKeepPressed:(AGSensitiveButton *)sButton forTime:(ccTime)pressTime;
@end

.h 文件：

#import "CCSprite.h"
#import "cocos2d.h"
#import "AGSensitiveButtonControlledObjectProtocol.h"

typedef enum {
    AGSensitiveButtonStateNormal = 0,
    AGSensitiveButtonStateHighlighted,
    AGSensitiveButtonStateDisabled
} AGSensitiveButtonState;

@interface AGSensitiveButton : CCSprite <CCTargetedTouchDelegate>

@property (nonatomic, assign, getter = isEnabled) BOOL enabled;
@property (nonatomic, assign) ccTime maximumTouchDuration;
@property (nonatomic, weak) id <AGSensitiveButtonControlledObjectProtocol> controlledObject;
@property (nonatomic, copy) void (^touchDownHandler)();
@property (nonatomic, copy) void (^touchUpHandler)();

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture;

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture;

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
             controllerObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject;

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture
             controlledObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject;

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture
             controlledObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject
             touchDownHandler:(void(^)(void))touchDownHandler
               touchUpHandler:(void(^)(void))touchUpHandler;

- (void)setTexture:(CCTexture2D *)texture forState:(AGSensitiveButtonState)state;

- (BOOL)isHighlighted;

@end

实现.m文件：

#import "AGSensitiveButton.h"

@interface AGSensitiveButton ()
@property (nonatomic, assign) AGSensitiveButtonState state;
@property (nonatomic, strong) NSDictionary *stateTextures;
@property (nonatomic, assign) ccTime currentTouchTime;
@end

@implementation AGSensitiveButton

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture {
    return [self buttonWithNormalTexture:normalTexture
                      highlightedTexture:highTexture
                        controllerObject:nil];
}

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture {
    return [self buttonWithNormalTexture:normalTexture
                      highlightedTexture:highTexture
                         disabledtexture:disabledTexture
                        controlledObject:nil];
}

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
             controllerObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject {
    return [self buttonWithNormalTexture:normalTexture
                      highlightedTexture:highTexture
                         disabledtexture:nil
                        controlledObject:controlledObject];
}

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture
             controlledObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject {
    return [self buttonWithNormalTexture:normalTexture
                      highlightedTexture:highTexture
                         disabledtexture:disabledTexture
                        controlledObject:controlledObject
                        touchDownHandler:NULL
                          touchUpHandler:NULL];
}

+ (id)buttonWithNormalTexture:(CCTexture2D *)normalTexture
           highlightedTexture:(CCTexture2D *)highTexture
              disabledtexture:(CCTexture2D *)disabledTexture
             controlledObject:(id <AGSensitiveButtonControlledObjectProtocol>)controlledObject
             touchDownHandler:(void(^)(void))touchDownHandler
               touchUpHandler:(void(^)(void))touchUpHandler {
    AGSensitiveButton *button = [[self alloc] initWithTexture:normalTexture
                                                         rect:CGRectMake(0.0, 0.0, normalTexture.contentSize.width, normalTexture.contentSize.height)];
    [button setTexture:normalTexture forState:AGSensitiveButtonStateNormal];
    [button setTexture:highTexture forState:AGSensitiveButtonStateHighlighted];
    [button setTexture:disabledTexture forState:AGSensitiveButtonStateDisabled];
    button.controlledObject = controlledObject;
    button.touchDownHandler = touchDownHandler;
    button.touchUpHandler = touchUpHandler;
    return button;
}

- (void)setEnabled:(BOOL)enabled {
    [self setupNewState:enabled ? AGSensitiveButtonStateNormal : AGSensitiveButtonStateDisabled];
}

- (BOOL)isEnabled {
    return (self.state != AGSensitiveButtonStateDisabled);
}

- (BOOL)isHighlighted {
    return (self.state == AGSensitiveButtonStateHighlighted);
}

- (void)toggleTextureForCurrentState {
    CCTexture2D *textureToSet = [self.stateTextures objectForKey:[NSNumber numberWithInteger:self.state]];
    if (textureToSet) {
        self.texture = textureToSet;
        self.textureRect = CGRectMake(0.0, 0.0, textureToSet.contentSize.width, textureToSet.contentSize.height);
    }
}

- (void)setTexture:(CCTexture2D *)texture forState:(AGSensitiveButtonState)state {
    NSMutableDictionary *newStates = self.stateTextures.mutableCopy;
    if (texture) {
        [newStates setObject:texture forKey:[NSNumber numberWithInteger:state]];
    } else {
        [newStates removeObjectForKey:[NSNumber numberWithInteger:state]];
    }
    self.stateTextures = newStates.copy;
}

- (NSDictionary *)stateTextures {
    if (!_stateTextures) {
        _stateTextures = [[NSDictionary alloc] init];
    }
    return _stateTextures;
}

- (void)onEnter {
    [super onEnter];
    [self toggleTextureForCurrentState];
    [[[CCDirector sharedDirector] touchDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES];
    [self scheduleUpdate];
}

- (void)onExit {
    [super onExit];
    [self unscheduleUpdate];
    [[[CCDirector sharedDirector] touchDispatcher] removeDelegate:self];
}

- (void)update:(ccTime)dt {
    if ((self.state == AGSensitiveButtonStateHighlighted) && (self.maximumTouchDuration)) {
        self.currentTouchTime+=dt;
        if (self.currentTouchTime >= self.maximumTouchDuration) {
            [self ccTouchEnded:nil withEvent:nil];
    } else {
        if ([self.controlledObject respondsToSelector:@selector(sensitiveTouchButtonKeepPressed:forTime:)]) {
            [self.controlledObject sensitiveTouchButtonKeepPressed:self forTime:self.currentTouchTime];
        }
    }
    }
}

- (CGRect)rectForTouches {
    return CGRectMake(-self.contentSize.width/2, -self.contentSize.height/2,
                      self.contentSize.width, self.contentSize.height);
}

- (void)forwardTouchDownEventIntoHandlers {
    if ([self.controlledObject respondsToSelector:@selector(sensitiveButtonTouchDown:)]) {
        [self.controlledObject sensitiveButtonTouchDown:self];
    }
    if (self.touchDownHandler) {
        self.touchDownHandler();
    }
}

- (void)forwardTouchUpEventIntoHandlers {
    if ([self.controlledObject respondsToSelector:@selector(sensitiveButtonTouchUp:)]) {
        [self.controlledObject sensitiveButtonTouchUp:self];
    }
    if (self.touchUpHandler) {
        self.touchUpHandler();
    }
}

- (void)setupNewState:(AGSensitiveButtonState)state {
    if (self.state != state) {
        switch (state) {
            case AGSensitiveButtonStateHighlighted: {
                [self forwardTouchDownEventIntoHandlers];
                break;
            }
            default: {
                if (self.state == AGSensitiveButtonStateHighlighted) {
                    [self forwardTouchUpEventIntoHandlers];
                }
                break;
            }
        }
        self.state = state;
        [self toggleTextureForCurrentState];
    }
}

#pragma mark - CCTargetedTouchDelegate

- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    if ((self.state != AGSensitiveButtonStateNormal) || (!CGRectContainsPoint([self rectForTouches], [self convertTouchToNodeSpaceAR:touch]))) {
        return NO;
    }
    self.currentTouchTime = 0.0;
    [self setupNewState:AGSensitiveButtonStateHighlighted];
    return YES;
}

- (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event {
    if (self.state == AGSensitiveButtonStateHighlighted) {
        if (!CGRectContainsPoint([self rectForTouches], [self convertTouchToNodeSpaceAR:touch])) {
            [self ccTouchEnded:touch withEvent:event];
        }
    }
}

- (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event {
    if (self.state == AGSensitiveButtonStateHighlighted) {
        [self setupNewState:AGSensitiveButtonStateNormal];
    }
}

@end