xcode的CGPoint arc4random不工作

我有22张图片... 11（rightwall1，rightwall2，rightwall3等），其他11（leftwall1，leftwall2，leftwall3等）xcode的CGPoint arc4random不工作

我把每一个ontop的的另一种方法是将它们的y值设置为之前的墙壁y值加上墙壁的高度（所有墙壁都是相同的高度）。

这工作正常！现在

，我试图用arc4random设置x的值，这样他们就活蹦乱跳在一定范围内的地方......

右壁完美，但左侧墙壁，其中一些工作但其中大部分没有显示在屏幕上。

我手动将x值设置为-15，它出现在屏幕上，并且低于arc4random允许的值。

我能想到的唯一问题是我正在减去左墙的错误？

下面是设置墙位置的代码，我在整个项目中没有其他代码。

-(void)awakeFromNib { 

    rightWall1.center = CGPointMake(((arc4random()%75)+330), (460-((rightWall1.frame.size.height)/2)));//460 = bottom of screen 
    rightWall2.center = CGPointMake(((arc4random()%75)+330), ((rightWall1.center.y)-(rightWall2.frame.size.height))); 
    rightWall3.center = CGPointMake(((arc4random()%75)+330), ((rightWall2.center.y)-(rightWall3.frame.size.height))); 
    rightWall4.center = CGPointMake(((arc4random()%75)+330), ((rightWall3.center.y)-(rightWall4.frame.size.height))); 
    rightWall5.center = CGPointMake(((arc4random()%75)+330), ((rightWall4.center.y)-(rightWall5.frame.size.height))); 
    rightWall6.center = CGPointMake(((arc4random()%75)+330), ((rightWall5.center.y)-(rightWall6.frame.size.height))); 
    rightWall7.center = CGPointMake(((arc4random()%75)+330), ((rightWall6.center.y)-(rightWall7.frame.size.height))); 
    rightWall8.center = CGPointMake(((arc4random()%75)+330), ((rightWall7.center.y)-(rightWall8.frame.size.height))); 
    rightWall9.center = CGPointMake(((arc4random()%75)+330), ((rightWall8.center.y)-(rightWall9.frame.size.height))); 
    rightWall10.center = CGPointMake(((arc4random()%75)+330), ((rightWall9.center.y)-(rightWall10.frame.size.height))); 
    rightWall11.center = CGPointMake(((arc4random()%75)+330), ((rightWall10.center.y)-(rightWall11.frame.size.height))); 


    leftWall1.center = CGPointMake(((arc4random()%75)-60), (460-((leftWall1.frame.size.height)/2))); 
    leftWall2.center = CGPointMake(((arc4random()%75)-60), ((leftWall1.center.y)-(leftWall2.frame.size.height))); 
    leftWall3.center = CGPointMake(((arc4random()%75)-60), ((leftWall2.center.y)-(leftWall3.frame.size.height))); 
    leftWall4.center = CGPointMake(((arc4random()%75)-60), ((leftWall3.center.y)-(leftWall4.frame.size.height))); 
    leftWall5.center = CGPointMake(((arc4random()%75)-60), ((leftWall4.center.y)-(leftWall5.frame.size.height))); 
    leftWall6.center = CGPointMake(((arc4random()%75)-60), ((leftWall5.center.y)-(leftWall6.frame.size.height))); 
    leftWall7.center = CGPointMake(((arc4random()%75)-60), ((leftWall6.center.y)-(leftWall7.frame.size.height))); 
    leftWall8.center = CGPointMake(((arc4random()%75)-60), ((leftWall7.center.y)-(leftWall8.frame.size.height))); 
    leftWall9.center = CGPointMake(((arc4random()%75)-60), ((leftWall8.center.y)-(leftWall9.frame.size.height))); 
    leftWall10.center = CGPointMake(((arc4random()%75)-60), ((leftWall9.center.y)-(leftWall10.frame.size.height))); 
    leftWall11.center = CGPointMake(((arc4random()%75)-60), ((leftWall10.center.y)-(leftWall11.frame.size.height))); 

}

来源

2011-05-30 Albert Renshaw

手动设置一个以-15的x值，并在屏幕上出现了，那就是低于arc4random允许它去。 -60和14之间

((arc4random()%75)-60)收益数字，因为OHHHHHHHHHHHHHHHH介于0和74

来源

2011-05-30 15:43:26

(arc4random()%75)回报数字！ HAHAHHAHAHAHAHAHHAHAHAAH – 2011-05-30 17:39:54

尽管仍然没有工作，问题是当处理负arc4random值你不能使用整数你必须使用浮动..如果减去你不能只减去你必须添加arc4random乘以负1 float值。这是因为arc4random使用我假设的模... – 2011-05-31 04:52:57

arc4random返回无符号值。使用％限制范围。你不需要浮点数 - 只是在％之后的有符号整数。 – 2011-05-31 11:53:35

xcode的CGPoint arc4random不工作

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