Arc4随机错误："Invalid operands to binary expression ('float' and 'float')"

Question

我想在特定视图中的任意位置创建一个按钮。我搜索并阅读了一些SO主题，但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（%）不适用于浮点运算。

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));

---

另请注意，不建议使用arc4random() % …。

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));

至

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)));

它可能会抛出这个错误，因为您正试图使用浮点作为参数来计算模量