1.扩展图片

// 通过颜色生成图片
extension UIImage{
    
    class func createImage(with color: UIColor, size:CGSize) -> UIImage{
        let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()
        context!.setFillColor(color.cgColor)
        context!.fill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return image!
    }
}

2.扩展颜色

// 通过16进制生成颜色
extension UIColor {
   
    convenience init(hexColor: String,alpha:CGFloat) {  
        // 存储转换后的数值
        var red:UInt32 = 0, green:UInt32 = 0, blue:UInt32 = 0      
        // 分别转换进行转换 // 这个地方需要使用到扩展字符串的下标截取
        Scanner(string: hexColor[0..<2]).scanHexInt32(&red)    
        Scanner(string: hexColor[2..<4]).scanHexInt32(&green)   
        Scanner(string: hexColor[4..<6]).scanHexInt32(&blue)
        
        self.init(red: CGFloat(red)/255.0, green: CGFloat(green)/255.0, blue: CGFloat(blue)/255.0, alpha: alpha)
    } 
}

3.扩展字符串

extension String {
    
    /// String使用下标截取字符串
    /// 例: "示例字符串"[0..<2] 结果是 "示例"
    subscript (r: Range<Int>) -> String {
        get {
            let startIndex = self.index(self.startIndex, offsetBy: r.lowerBound)
            let endIndex = self.index(self.startIndex, offsetBy: r.upperBound)
            
            return self[startIndex..<endIndex]
        }
    }
    // md5校验
    func md5() -> String {
        let str = self.cString(using: String.Encoding.utf8)
        let strLen = CUnsignedInt(self.lengthOfBytes(using: String.Encoding.utf8))
        let digestLen = Int(CC_MD5_DIGEST_LENGTH)
        let result = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: digestLen)
        CC_MD5(str!, strLen, result)
        let hash = NSMutableString()
        for i in 0 ..< digestLen {
            hash.appendFormat("%02x", result[i])
        }
        result.deinitialize()
        
        return String(format: hash as String)
    }
    
    
    // 对象方法 (获取文件大小)
    func getFileSize() -> UInt64  {
        var size: UInt64 = 0
        let fileManager = FileManager.default
        var isDir: ObjCBool = false
        let isExists = fileManager.fileExists(atPath: self, isDirectory: &isDir)
        // 判断文件存在
        if isExists {
            // 是否为文件夹
            if isDir.boolValue {
                // 迭代器 存放文件夹下的所有文件名
                let enumerator = fileManager.enumerator(atPath: self)
                for subPath in enumerator! {
                    // 获得全路径
                    let fullPath = self.appending("/\(subPath)")
                    do {
                        let attr = try fileManager.attributesOfItem(atPath: fullPath)
                        size += attr[FileAttributeKey.size] as! UInt64
                    } catch  {
                        print("error :\(error)")
                    }
                }
            } else {    // 单文件
                do {
                    let attr = try fileManager.attributesOfItem(atPath: self)
                    size += attr[FileAttributeKey.size] as! UInt64
                    
                } catch  {
                    print("error :\(error)")
                }
            }
        }
        return size
    }
}

4.计算字符串高度

    // 计算Label高度
    static func textHeight(_ text : String , fontSize: CGFloat , maxWidth : CGFloat) -> CGFloat {
        
        return text.boundingRect(with: CGSize.init(width: maxWidth, height: CGFloat(MAXFLOAT)), options: [.usesLineFragmentOrigin], attributes: [NSFontAttributeName : UIFont.systemFont(ofSize: fontSize)], context: nil).size.height
    }

5.时间转换星期

    /// 时间转换星期
    static func getWeekDayFormDate(_ time: Int) -> String {
        
        let weekday: NSArray = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"] as NSArray
        
        let date = Date.init(timeIntervalSince1970: TimeInterval(time))
        
        let calendar = Calendar(identifier: .republicOfChina)
        
        let components = calendar.component(.weekday, from: date)
        let weekStr = weekday.object(at: components-1)
        
        
        return weekStr as! String
        
    }

5.金额单位转换

    static func calculatePriceUnit(_ price: Double) -> NSString{
        let array = ["元","万元","亿元","万亿元"]
        var tempPrice = 0.0
        
        for i in 0..<array.count{
            if 0 < price && price < pow(10000, Double(i + 1)) {
                tempPrice = i > 0 ? price / pow(10000, Double(i)) : price
                var str = NSString(format: "%.0f", tempPrice)
                str = "\(str) \(array[i])" as NSString
                return str
            }
        }
        return "错误"
        
    }

6.字节单位转换

    // 将字节(byte单位转换)
    static func transformSize(_ size: Double) -> String {
        var newSize: Double = 0

        // 小于1024byte
        if 0 < size && size < 1024 {
            
            return "\(size)B"
        }
        // 1B - 1M
        else if size < 1024 * 1024 {
            newSize = size / 1024.0
            let str = String(format: "%.1f", newSize)
            return str+"KB"
        }
        // 1M - 1G
        else if size < 1024 * 1024 * 1024 {
            newSize = size / (1024.0 * 1024.0)
            let str = String(format: "%.1f", newSize)
            return str+"M"
        }

        return "模型错误"
    
    }