iOS 16進位顏色轉換10進位顏色

+(UIColor *)colorWithHexString:(NSString *)coloStr{

//    檢索  去下空格和換行 轉成大寫

    NSString *cString = [[coloStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

    if (cString.length<6) {

        return [UIColor clearColor];

    }

//  看以什麼開頭

    if ([cString hasPrefix:@"0X"]) {

        cString = [cString substringFromIndex:2];

    }

    if ([cString hasPrefix:@"#"]) {

        cString = [cString substringFromIndex:1];

    }

    if ([cString length] != 6) {

        return [UIColor clearColor];

    }

//    截取字元串

    NSRange range;

    range.location = 0 ;

    range.length = 2 ;

    NSString *rString = [cString substringWithRange:range];

    range.location = 2;

    NSString *gString = [cString substringWithRange:range];

    range.location = 4;

    NSString *bString = [cString substringWithRange:range];

//    16進位轉化10進位

    unsigned int r , g , b ;

    [[NSScanner scannerWithString:rString] scanHexInt:&r];

    [[NSScanner scannerWithString:gString] scanHexInt:&g];

    [[NSScanner scannerWithString:bString] scanHexInt:&b];

    return [UIColor colorWithRed:((float)r/255.0f) green:((float)g/255.0f) blue:((float)b/255.0f) alpha:1.0];

}