目标C中的颜色变量 [英] Color Variables in Objective C

问题描述

如何在Obj C中设置和重用颜色变量？我正在尝试设置一个可重复使用的颜色值，例如：

How do I set and reuse a color variable in Obj C? I am trying to set a reusable color value as in this question:

使用变量iOS更改背景颜色

但不成功。

 UIColor *lightGrayHeader = [UIColor colorWithRed:246/255.f green:239/255.f blue:239/255.f alpha:1.0];

 self.view.backgroundColor = [UIColor lightGrayHeader];

返回错误： Initializer元素不是编译时常量。

Returns an error: "Initializer element is not a compile-time constant."

感谢您的想法！

推荐答案

您定义的是局部变量。它的用法如下：

What you have defined is a local variable. It is used like this:

UIColor *lightGrayHeader = [UIColor colorWithRed:246/255.f green:239/255.f blue:239/255.f alpha:1.0];
self.view.backgroundColor = lightGrayHeader;

如果要在 UIColor 获取颜色，您可以执行以下操作：

If you want to use a static method on UIColor to fetch a colour, you could do this:

@interface UIColor (MyColours)
+ (instancetype)lightGrayHeader;
@end

@implementation UIColor (MyColours)
+ (instancetype)lightGrayHeader {
  return [self  colorWithRed:246/255.f green:239/255.f blue:239/255.f alpha:1.0];
}
@end

然后只要导入 UIColor（MyColours）头，您可以使用：

And then as long as you import the UIColor (MyColours) header, you could use:

self.view.backgroundColor = [UIColor lightGrayHeader];

这篇关于目标C中的颜色变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！