如何将UIColor转换为十六进制字符串？

I have a project where I need to store the RGBA values of a UIColor in a database as an 8-character hexadecimal string. For example, [UIColor blueColor] would be @"0000FFFF". I know I can get the component values like so:

我有一个项目，我需要将UIColor的RGBA值作为8个字符的十六进制字符串存储在数据库中。例如，[UIColor blueColor]将是@“0000FFFF”。我知道我可以像这样得到组件值：

CGFloat r,g,b,a;
[color getRed:&r green:&g blue: &b alpha: &a];

but I don't know how to go from those values to the hex string. I've seen a lot of posts on how to go the other way, but nothing functional for this conversion.

但我不知道如何从这些值转到十六进制字符串。我已经看过很多关于如何走另一条路的帖子，但这个转换没有任何功能。

2 个解决方案

#1

Get your floats converted to int values first, then format with stringWithFormat:

首先将浮点数转换为int值，然后使用stringWithFormat格式化：

    int r,g,b,a;

    r = (int)(255.0 * rFloat);
    g = (int)(255.0 * gFloat);
    b = (int)(255.0 * bFloat);
    a = (int)(255.0 * aFloat);

    [NSString stringWithFormat:@"%02x%02x%02x%02x", r, g, b, a];

#2

Here it goes. Returns a NSString (e.g. ffa5678) with a hexadecimal value of the color.

在这里。返回具有颜色的十六进制值的NSString（例如ffa5678）。

- (NSString *)hexStringFromColor:(UIColor *)color
{
    const CGFloat *components = CGColorGetComponents(color.CGColor);

    CGFloat r = components[0];
    CGFloat g = components[1];
    CGFloat b = components[2];

    return [NSString stringWithFormat:@"%02lX%02lX%02lX",
            lroundf(r * 255),
            lroundf(g * 255),
            lroundf(b * 255)];
}

#1