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cocos2d中CCCallFuncND传参数的注意事项

2013-03-21 16:05 369 查看




A.用CCFuncBlock可以不用传参数,代码简洁高效,函数内临时变量如果不retain,不存在跳出函数使用域后被回收情况(推荐)

//用CCCallBlock的block方式
CGPoint convertedLocation = [self convertTouchToNodeSpace:touch];
CCCallBlock *block = [CCCallBlock actionWithBlock:^{
            //回调方法在一个函数循环内3个好处:
          1.不用传递(void *)参数,所以convertedLocation不需要封装,
          2.传递指针类型变量(非alloc或copy)也不需要retain,
          3.alloc或copy方式产生的参数,函数内释放,省去函数外手动释放的麻烦。
            [self flightBezier:convertedLocation];
            }];
[flight runAction:[CCSequence actions:[CCMoveTo actionWithDuration:1 position:ccp(convertedLocation.x,convertedLocation.y)], block, nil]];


B.使用CCFuncND传递参数(void *)类型,若想传递CGPoint等非指针类型参数,,有两种方法:

1.传递参数地址,注意参数必须为静态变量,否则参数地址一出循环即被系统回收。

-(void) ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
  UITouch *touch = [touches anyObject];
static _startPos;
CGPoint convertedLocation = [self convertTouchToNodeSpace:touch];
  _startPos = converedLocation;
   //传递&_startPos
id call = [CCCallFuncND actionWithTarget:self selector:@selector(call:data:) data:(void *)&_startPos];
[flight runAction:[CCSequence actions:[CCMoveTo actionWithDuration:1 position:ccp(convertedLocation.x,convertedLocation.y)], call, nil]];
return;
}


回调:

- (void)call:(id)sender data:(void *)point
{
  //sender即为flight指针
//传递&_startPos;
CGPoint p = *(CGPoint *) point;
[self flightBezier:p];
}


2.如果想传递CGPoint等非指针类型变量, 可以封装成NSValue再传递

-(void) ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
  UITouch *touch = [touches anyObject];
static _startPos;
CGPoint convertedLocation = [self convertTouchToNodeSpace:touch];
  _startPos =converedLocation;

//传递nsvalue封装的cgpoint
NSValue *va = [[NSValuevalueWithCGPoint:convertedLocation]retain];//这里不能加autorease
id call1 = [CCCallFuncND actionWithTarget:self selector:@selector(call:data:) data:(void *)va];
[flight runAction:[CCSequence actions:[CCMoveTo actionWithDuration:1 position:ccp(convertedLocation.x,convertedLocation.y)], call1, nil]];
return;
}


回调:

- (void)call:(id)sender data:(void *)point
{
 //传递nsvalue
CGPoint p = [((NSValue *)point) CGPointValue];
  //父变量,子释放,比较忌讳,但是没找到好的解决办法先凑合用
[(NSValue *)point release];
point = nil;
[self flightBezier:p];
}


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