iOS开发之从UIColo到十六进制

今天开发中需要将UIColor转为十六进制字符串，记录下修改代码

        UIColor *color = [UIColor blueColor];
        const CGFloat* components = CGColorGetComponents(color.CGColor);
        NSString *alpha = [self getHexByDecimal:CGColorGetAlpha(color.CGColor)*255.0];
        NSString *red = [self getHexByDecimal:components[0]*255.0];
        NSString *green = [self getHexByDecimal:components[1]*255.0];
        NSString *blue = [self getHexByDecimal:components[2]*255.0];
        NSSTring colorStr = [NSString stringWithFormat:@"#%@%@%@%@", alpha, red, green, blue];

/** 十进制转十六进制*/
+ (NSString *)getHexByDecimal:(NSInteger)decimal
{
    NSString *hex =@"";
    NSString *letter;
    NSInteger number;
    for (int i = 0; i<9; i++) {
        number = decimal % 16;
        decimal = decimal / 16;
        switch (number) {
            case 10:
                letter =@"A"; break;
            case 11:
                letter =@"B"; break;
            case 12:
                letter =@"C"; break;
            case 13:
                letter =@"D"; break;
            case 14:
                letter =@"E"; break;
            case 15:
                letter =@"F"; break;
            default:
                letter = [NSString stringWithFormat:@"%ld", number];
        }
        hex = [letter stringByAppendingString:hex];
        if (decimal == 0) {
            
            break;
        }
    }
    return hex;
}