Question

我想在某个视图中的随机位置创建一个按钮。我搜索并阅读了一些SO主题但是我找不到解决问题的方法。

这是我的代码：

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect buttonRect = button1.frame;
buttonRect.size = CGSizeMake(100, 100);
button1.frame = buttonRect;

[self.arr addObject:button1];

int r = ([button1 frame].size.width)/2;

int x = r + (arc4random() % (self.view.frame.size.width - button1.frame.size.width));
int y = r + (arc4random() % (self.view.frame.size.height - button1.frame.size.height));
//ERROR:Invalid operands to binary expression ('float' and 'float')

[button1 setCenter:CGPointMake(x, y)];

Answer 1

mod（％）对浮点数不起作用。

int x = r + (arc4random() % (int)(self.view.frame.size.width - button1.frame.size.width));
int y = r + (arc4random() % (int)(self.view.frame.size.height - button1.frame.size.height));

作为补充说明，arc4random() % …为not recommended。

以下是首选方法：

int x = r + arc4random_uniform(self.view.frame.size.width - button1.frame.size.width);
int y = r + arc4random_uniform(self.view.frame.size.height - button1.frame.size.height);

Answer 2

尝试更改

int x = r + (arc4random() % (self.view.frame.size.width - button1.frame.size.width));
int y = r + (arc4random() % (self.view.frame.size.height - button1.frame.size.height));

到

int x = r + (arc4random() % ((int)(self.view.frame.size.width - button1.frame.size.width)));
int y = r + (arc4random() % ((int)(self.view.frame.size.height - button1.frame.size.height)));

它可能会抛出该错误，因为您尝试使用float作为参数计算模数

Arc4random错误：“二进制表达式的操作数无效（'float'和'float'）”

2 个答案: