iOS 常用RGB十六进制颜色转换方法
2018-12-26 本文已影响0人
Levi段玉磊
iOS 常用RGB十六进制颜色转换方法
需求
正常美术出图都是给你十六进制编码,然后让我们在Xcode中,对颜色进行赋值,由于iOS的UIColor并未提供方法直接使用十六进制编码对设置颜色的场景进行赋值,所以我们需要造个小轮子。
实现方式
通过分类的方法实现:
UIColor+Addition.h
@interface UIColor (Addition)
//设置RGB颜色
+ (UIColor *)red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue alpha:(CGFloat)alpha;
//将颜色转换成RGB
+ (NSArray *)convertColorToRGB:(UIColor *)color;
//设置十六进制颜色
+ (UIColor *)colorWithHex:(NSInteger)hex;
+ (UIColor *)colorWithHexString:(NSString *)hexString;
+ (UIColor *)colorWithHexString:(NSString *)hexString alpha:(CGFloat)alpha
@end
UIColor+Addition.m
#import "UIColor+Addition.h"
@implementation UIColor (Addition)
+ (UIColor *)red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue alpha:(CGFloat)alpha {
return [UIColor colorWithRed:red/255.0 green:green/255.0 blue:blue/255.0 alpha:alpha];
}
+ (NSArray *)convertColorToRGB:(UIColor *)color {
NSInteger numComponents = CGColorGetNumberOfComponents(color.CGColor);
NSArray *array = nil;
if (numComponents == 4) {
const CGFloat *components = CGColorGetComponents(color.CGColor);
array = @[@((int)(components[0] * 255)),
@((int)(components[1] * 255)),
@((int)(components[2] * 255))];
}
return array;
}
+ (UIColor *)colorWithHex:(NSInteger)hex {
return [UIColor colorWithRed:((float)((hex & 0xff0000) >> 16))/255.0 green:((float)((hex & 0x00ff00) >> 8))/255.0 blue:((float)(hex & 0x0000ff))/255.0 alpha:1.0];
}
+ (UIColor *)colorWithHexString:(NSString *)hexString
{
NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];
CGFloat alpha, red, blue, green;
switch ([colorString length]) {
case 3: // #RGB
alpha = 1.0f;
red = [self colorComponentFrom: colorString start: 0 length: 1];
green = [self colorComponentFrom: colorString start: 1 length: 1];
blue = [self colorComponentFrom: colorString start: 2 length: 1];
break;
case 4: // #ARGB
alpha = [self colorComponentFrom: colorString start: 0 length: 1];
red = [self colorComponentFrom: colorString start: 1 length: 1];
green = [self colorComponentFrom: colorString start: 2 length: 1];
blue = [self colorComponentFrom: colorString start: 3 length: 1];
break;
case 6: // #RRGGBB
alpha = 1.0f;
red = [self colorComponentFrom: colorString start: 0 length: 2];
green = [self colorComponentFrom: colorString start: 2 length: 2];
blue = [self colorComponentFrom: colorString start: 4 length: 2];
break;
case 8: // #AARRGGBB
alpha = [self colorComponentFrom: colorString start: 0 length: 2];
red = [self colorComponentFrom: colorString start: 2 length: 2];
green = [self colorComponentFrom: colorString start: 4 length: 2];
blue = [self colorComponentFrom: colorString start: 6 length: 2];
break;
default:
blue=0;
green=0;
red=0;
alpha=0;
break;
}
return [UIColor colorWithRed: red green: green blue: blue alpha: alpha];
}
+ (CGFloat)colorComponentFrom:(NSString *)string start:(NSUInteger)start length:(NSUInteger) length
{
NSString *substring = [string substringWithRange: NSMakeRange(start, length)];
NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];
unsigned hexComponent;
[[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];
return hexComponent / 255.0;
}
+ (UIColor *)colorWithHexString:(NSString *)hexString alpha:(CGFloat)alpha
{
NSString *cString = [[hexString stringByTrimmingCharactersInSet:
[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
if ([cString length] < 6) {
return [UIColor whiteColor];
}
if ([cString hasPrefix:@"#"]) {
cString = [cString substringFromIndex:1];
}
if ([cString length] != 6) {
return [UIColor whiteColor];
}
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];
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:alpha];
}
思考与总结:
需要记住的是:
纯黑是 #000000
纯白是 #FFFFFF