游戏启动画面设计
效果：
1) 游戏主画面加在完毕
2) 进程图片渐现、渐隐(Ready, Set, Go!)
3) 进入游戏
思路：
通过图片加载生成CCSprite实例后构造包含多个Action的CCSequence：
图片渐显(CCFadeIn)图片放大(CCScaleTo)图片淡出(CCFadeOut)执行回调(CCCallFuncN)【说实话，没太搞明白】
代码：
CCSprite * ready = [CCSprite spriteWithFile:@"ready.png"];[self addChild:ready z:3];[ready setPosition:ccp(240,160)];[ready setOpacity:0];CCSprite * set =[CCSprite spriteWithFile:@"set.png"];[self addChild:set z:3];[set setPosition:ccp(240,160)];[set setOpacity:0];CCSprite * go = [CCSprite spriteWithFile:@"go.png"];[self addChild:go z:3];[go setPosition:ccp(240,160)];[go setOpacity:0];[ready runAction:[CCSequence actions:[CCDelayTime actionWithDuration:0.5],[CCSpawn actions:[CCFadeIn actionWithDuration:0.4],[CCScaleTo actionWithDuration:0.4 scale:1.2],nil] ,[CCDelayTime actionWithDuration:0.2],[CCFadeOut actionWithDuration:0.4],[CCCallFuncN actionWithTarget:self selector:@selector(removeSprite:)],nil]];[set runAction:[CCSequence actions:[CCDelayTime actionWithDuration:1.5],[CCSpawn actions:[CCFadeIn actionWithDuration:0.4],[CCScaleTo actionWithDuration:0.4 scale:1.2],nil] ,[CCDelayTime actionWithDuration:0.2],[CCFadeOut actionWithDuration:0.4],[CCCallFuncN actionWithTarget:self selector:@selector(removeSprite:)],nil]];[go runAction:[CCSequence actions:[CCDelayTime actionWithDuration:2.5],[CCSpawn actions:[CCFadeIn actionWithDuration:0.4],[CCScaleTo actionWithDuration:0.4 scale:1.2],nil] ,[CCDelayTime actionWithDuration:0.2],[CCFadeOut actionWithDuration:0.4],[CCCallFuncN actionWithTarget:self selector:@selector(removeSpriteAndBegin:)],nil]];
