来自转载：http://my.oschina.net/leejan97/blog/307491
摘要： 可以直接使用十六进制设置控件的颜色，而不必通过除以255.0进行转换
新建一个Category，命名为UIColor+Hex，表示UIColor支持十六进制Hex颜色设置。
UIColor+Hex.h文件
#import <UIKit/UIKit.h>
//RGB颜色设置 #define RGBA_COLOR(R, G, B, A) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:A] #define RGB_COLOR(R, G, B) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:1.0f] @interface UIColor (Hex) + (UIColor *)colorWithHexString:(NSString *)color; //从十六进制字符串获取颜色， //color:支持@“#123456”、 @“0X123456”、 @“123456”三种格式 + (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha; @end
上面的代码在开头是两个宏定义，就是对[UIColor colorWithRed:green:blue:alpha]方法的简化，在UIColor(Hex)中声明两个方法-colorWithHexString和-colorWithHexString:alpha，这个很好理解。
UIColor+Hex.m文件
#import "UIColor+Hex.h" @implementation UIColor (Hex) + (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha { //删除字符串中的空格 NSString *cString = [[color stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString]; // String should be 6 or 8 characters if ([cString length] < 6) { return [UIColor clearColor]; } // strip 0X if it appears //如果是0x开头的，那么截取字符串，字符串从索引为2的位置开始，一直到末尾 if ([cString hasPrefix:@"0X"]) { cString = [cString substringFromIndex:2]; } //如果是#开头的，那么截取字符串，字符串从索引为1的位置开始，一直到末尾 if ([cString hasPrefix:@"#"]) { cString = [cString substringFromIndex:1]; } if ([cString length] != 6) { return [UIColor clearColor]; } // Separate into r, g, b substrings NSRange range; range.location = 0; range.length = 2; //r NSString *rString = [cString substringWithRange:range]; //g range.location = 2; NSString *gString = [cString substringWithRange:range]; //b range.location = 4; NSString *bString = [cString 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:alpha]; } //默认alpha值为1 + (UIColor *)colorWithHexString:(NSString *)color { return [self colorWithHexString:color alpha:1.0f]; } @end
这样就扩展了UIColor，支持十六进制颜色设置。下面举个栗子，设置UIButton一些颜色特征，来说明该扩展的使用，
#import "UIColor+Hex.h" //省略多余的代码 //设置导航栏右侧的BarButtonItem为Button - (void)setupNavigationItem { UIView *rightView = [[UIView alloc] init]; rightView.bounds = CGRectMake(0, 0, 52, 44); UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeCustom]; rightButton.frame = CGRectMake(-6, 0, 52, 44); rightButton.backgroundImageEdgeInsets = UIEdgeInsetsMake(7, 0, 7, 0); //kSetting是国际化的字符串"设置" [rightButton setTitle:NVSLocalizedString(@"kSetting", nil) forState:UIControlStateNormal]; //使用宏定义的RGB_COLOR // [rightButton setTitleColor:RGB_COLOR(160, 170, 150) forState:UIControlStateHighlighted]; //使用UIColor+Hex扩展 [rightButton setTitleColor:[UIColor colorWithHexString:@"#708c3b"] forState:UIControlStateNormal]; rightButton.titleLabel.font = [UIFont fontWithName:@"Heiti SC" size:12.f]; [rightButton setBackgroundImage:[UIImage imageNamed:@"device_setting_bg"] forState:UIControlStateNormal]; [rightButton setBackgroundImage:[UIImage imageNamed:@"device_setting_bg_press"] forState:UIControlStateHighlighted]; [rightButton addTarget:self action:@selector(settingBtnPresss:) forControlEvents:UIControlEventTouchUpInside]; [rightView addSubview:rightButton]; UIBarButtonItem *rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:rightView]; [self.navigationItem setRightBarButtonItem:rightBarButtonItem animated:YES]; [rightBarButtonItem release]; [rightView release]; }
使用差不多就这么简单，总结一下，本篇博客主要有以下几个细节或者说知识点，
（1）宏定义RGB_COLOR和RGBA_COLOR可以设置颜色
（2）UIColor+Hex扩展可以设置颜色
（3）导航栏上面的BarButtonItem怎么设置为Button
（4）Button一些常用和不常用的属性设置
