1.建立一個UIColor的category,命名為UIColor+Helper

然后在UIColor+Helper.h中:

//16進制字符串轉換成UIColor,返回UIColor

+ (UIColor *)colorWithHexStr:(NSString *)colorStr;

在UIColor+Helper.m中:

//16進制字符串轉換成UIColor

+ (UIColor *)colorWithHexStr:(NSString *)colorStr{

    NSString * redStr = [colorStr substringWithRange:NSMakeRange(0, 2)];

    NSScanner * redScanner = [NSScanner scannerWithString:redStr];

    unsigned int redIntValue;

    [redScanner scanHexInt:&redIntValue];

    NSString * greenStr = [colorStr substringWithRange:NSMakeRange(2, 2)];

    NSScanner * greenScanner = [NSScanner scannerWithString:greenStr];

    unsigned int greenIntValue;

    [greenScanner scanHexInt:&greenIntValue];

    NSString * blueStr = [colorStr substringWithRange:NSMakeRange(4, 2)];

    NSScanner * blueScanner = [NSScanner scannerWithString:blueStr];

    unsigned int blueIntValue;

    [blueScanner scanHexInt:&blueIntValue];

    return [UIColor colorWithRed:redIntValue/255.0 green:greenIntValue/255.0 blue:blueIntValue/255.0 alpha:1];

}

 多數用于服務器后端傳值,然后前端將16進制的色值展示出來