iphone - xcode 工具查找内存问题，访问指向另一个变量 ecc 位置的指针

Question

我正在使用 cocos2d，但是这个问题很笼统。 我有课

CCNode *scaleLayer

在我设置的touchesMoved事件中

scaleLayer.scale=(some calculation)

如果我在设备中编译程序崩溃，在模拟器上运行良好。 如果我将 nslogs 放在前面的指令之前，即使在设备中也能很好地工作。 可能是一些内存，指针或者它可能是什么？ 但是，是否存在一个 xcode 工具可以让我找到或理解我的眼睛指向哪里？ 谢谢

代码如下:

- (void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSSet *allTouches = [event allTouches];
//NSLog(@"comincio");
switch ([allTouches count]) {
    case 2: { //Double Touch
        UITouch *t1 = [[allTouches allObjects] objectAtIndex:0];
        UITouch *t2 = [[allTouches allObjects] objectAtIndex:1];
        CGPoint p1=[self convertTouchToNodeSpace: t1];
        CGPoint p2=[self convertTouchToNodeSpace: t2];                  

        initialDistance = [self distanceBetweenTwoPoints:p1 B:p2];
        oldScale=scaleLayer.scale;
        NSLog(@"distanza iniz %f",initialDistance);
    } break;
            default:
        break;
}
}

-(void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    CGPoint location;   
    UITouch *t1,*t2;    
    CGPoint p1,p2;

    NSSet *allTouces=[event allTouches];
    switch ([allTouces count]) {
case 2:
            //NSLog(@"2 tocchi");
            t1=[[allTouces allObjects] objectAtIndex:0];
            t2=[[allTouces allObjects] objectAtIndex:1];
            p1=[self convertTouchToNodeSpace: t1];
            p2=[self convertTouchToNodeSpace: t2];
            CGFloat finalDistance=[self distanceBetweenTwoPoints:p1 B:p2];
//if i put here NSLog("%f %f %f",oldScale,finalDistance,initialDistance); all goes well
            scaleLayer.scale=oldScale*finalDistance/initialDistance;
            NSLog(@"scala %f",scaleLayer.scale);//finalDistance/initialDistance);
//this nslog give me error if i not put that nslog before
            break;

        default:
            break;
    }
}

-(CGFloat)distanceBetweenTwoPoints:(CGPoint)A B:(CGPoint)B{
    float x=B.x-A.x;
    float y=B.y-A.y;
    return sqrt(x*x+y*y);
}

Answer 1

尝试使用静态分析器 (Shift-Command-A) 构建

尝试观察内存地址。以下是一些帮助您入门的链接: scottmpeak.com和 SO discussion