convert a hexadecimal color (e.g. #FFCC88)

The following is a simple method that will convert a hexadecimal color (e.g. #FFCC88) into an equivalent UIColor object.
- (UIColor *) colorForHex:(NSString *)hexColor {
hexColor = [[hexColor stringByTrimmingCharactersInSet:
[NSCharacterSet whitespaceAndNewlineCharacterSet]
] uppercaseString];
// String should be 6 or 7 characters if it includes '#'
if ([hexColor length] < 6)
return [UIColor blackColor];
// strip # if it appears
if ([hexColor hasPrefix:@"#"])
hexColor = [cString substringFromIndex:1];
// if the value isn't 6 characters at this point return
// the color black
if ([hexColor length] != 6)
return [UIColor blackColor];
// Separate into r, g, b substrings
NSRange range;
range.location = 0;
range.length = 2;
NSString *rString = [hexColor substringWithRange:range];
range.location = 2;
NSString *gString = [hexColor substringWithRange:range];
range.location = 4;
NSString *bString = [hexColor substringWithRange:range];
// Scan values
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:1.0f];
}

Notice that we had to first separate our the hex values for the red, green, and blue components first as substrings and then apply the NSScanner to those substrings.

原文地址:https://www.cnblogs.com/cnsoft/p/1409040.html