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iOS开发-16进制颜色转换

日期：2017-06-28点击：421收藏

项目中经常会用到颜色转换，有的是通过十六进制转成数字转颜色，想简单的点直接通过字符串转一下，简单扩展了一下分类UIColor，代码如下:

     +(UIColor *)colorWithHex:( NSString  *)hexColor{ 
      return  [ self  colorWithHex:hexColor alpha:1.0f]; 
 } 
 //http://www.cnblogs.com/xiaofeixiang  iOS技术交流:228407086 
 +(UIColor *)colorWithHex:( NSString  *)hexColor alpha:( float )alpha{ 
      //删除空格 
      NSString  *colorStr = [[hexColor stringByTrimmingCharactersInSet:[ NSCharacterSet  whitespaceAndNewlineCharacterSet]] uppercaseString]; 
      // String should be 6 or 8 characters 
      if  ([colorStr length] < 6||[colorStr length]>7) 
      { 
          return  [UIColor clearColor]; 
      } 
      // 
      if  ([colorStr hasPrefix:@ "#" ]) 
      { 
          colorStr = [colorStr substringFromIndex:1]; 
      } 
   
      NSRange  range; 
      range.location = 0; 
      range.length = 2; 
      //red 
      NSString  *redString = [colorStr substringWithRange:range]; 
      //green 
      range.location = 2; 
      NSString  *greenString = [colorStr substringWithRange:range]; 
      //blue 
      range.location = 4; 
      NSString  *blueString= [colorStr substringWithRange:range]; 
       
      // Scan values 
      unsigned  int  red, green, blue; 
      [[ NSScanner  scannerWithString:redString] scanHexInt:&red]; 
      [[ NSScanner  scannerWithString:greenString] scanHexInt:&green]; 
      [[ NSScanner  scannerWithString:blueString] scanHexInt:&blue]; 
      return  [UIColor colorWithRed:(( float )red/ 255.0f) green:(( float )green/ 255.0f) blue:(( float )blue/ 255.0f) alpha:alpha]; 
 } 
 
  