在开发中，UI给出的颜色值有时候是十六进制的，有时候给出的是RGB(255,255,255)这样的形式的，而iOS系统提供的方法中并没有直接传递这两种值返回UIColor对象的，这里自己封装了一个以便使用。

UIColor+LMColor.h

#import <UIKit/UIKit.h>@interface UIColor(LMColor)/***  获取透明度为1的随机颜色**  @return 随机获得的UIColor对象*/
+ (UIColor *)randColor;/***  将16进制的颜色值转换成UIColor对象**  @param colorStr 16进制表示的颜色（0xc36000,0Xc36000,#c36000或者c36000格式都支持）*  @param alpha    透明度**  @return 转换过后的UIColor对象*/
+ (UIColor *)colorWithHexString:(NSString *)colorStr alpha:(CGFloat)alpha;/***  返回(168，57,23)表示形式的UIColor**  @param r 红，0～255*  @param g 绿，0～255*  @param b 蓝，0～255*  @param a 透明度，0～100**  @return 转换过后UIColor对象*/
+(UIColor *)colorWithR:(CGFloat)r g:(CGFloat)g b:(CGFloat)b a:(CGFloat)a;
@end

UIColor+LMColor.m

#import "UIColor+LMColor.h"@implementation UIColor(LMColor)+ (UIColor *)randColor {CGFloat r = arc4random_uniform(256);CGFloat g = arc4random_uniform(256);CGFloat b = arc4random_uniform(256);return [UIColor colorWithRed:r / 255.0f green:g / 255.0f blue:b / 255.0f alpha:1];
}+(UIColor *)colorWithR:(CGFloat)r g:(CGFloat)g b:(CGFloat)b a:(CGFloat)a{return [UIColor colorWithRed:r/255.0f green:g/255.0f blue:b/255.0f alpha:a/100.0f];
}+ (UIColor *)colorWithHexString:(NSString *)colorStr alpha:(CGFloat)alpha {//移除前缀if ([colorStr hasPrefix:@"0X"] || [colorStr hasPrefix:@"0x"]) {colorStr = [colorStr substringFromIndex:2];}if ([colorStr hasPrefix:@"#"]) {colorStr = [colorStr substringFromIndex:1];}//判断长度if (colorStr.length != 6) {return [UIColor clearColor];}//提取值NSRange range;range.length = 2;//rrange.location = 0;NSString *rStr = [colorStr substringWithRange:range];//grange.location = 2;NSString *gStr = [colorStr substringWithRange:range];//brange.location = 4;NSString *bStr = [colorStr substringWithRange:range];//转换值unsigned int r, g, b;[[NSScanner scannerWithString:rStr] scanHexInt:&r];[[NSScanner scannerWithString:gStr] scanHexInt:&g];[[NSScanner scannerWithString:bStr] scanHexInt:&b];return [UIColor colorWithRed:(r/255.0f) green:(g/255.0f) blue:(b/255.0f) alpha:alpha];
}
@end