Swift-Extension.swift

extension Character {
    func isHanzi() -> Bool {
        if ("\u{4E00}" <= self  && self <= "\u{9FA5}") {
            return true
        }else {
            return false
        }
    }
}

extension String {
    
    func characterCount() -> Int{ // 字符数：一个汉字 为 两个字符
        if count == 0 {
            return 0
        }
        
        var cCount = 0
        for (_, c) in enumerated() {
            if c.isHanzi() {
                cCount += 2
            }else {
                cCount += 1
            }
        }
        
        return cCount
    }
    
    // 根据字符数 裁剪
    func subString(count: Int)-> String {
        var remainCount = count
        var cCount = 0
        for (_, c) in enumerated(){
            if c.isHanzi(){
                remainCount -= 2
            }else {
                remainCount -= 1
            }
            if remainCount >= 0 {
                cCount += 1
            }else {
                break
            }
        }
        
        return String(prefix(cCount))
    }
}

extension Dictionary{
    func getJSONString() -> String {
        guard let data = getJSONData() else { return "" }
        guard let jsonString = String.init(data: data, encoding: .utf8)  else { return ""}
        return jsonString
    }
    
    func getJSONData() -> Data? {
        if (!JSONSerialization.isValidJSONObject(self)) {
            print("无法解析出JSONString")
            return nil
        }
        let data = try? JSONSerialization.data(withJSONObject: self, options: []) as Data
        return data
    }
    
}

extension Array{
    func getJSONData() -> Data? {
        if (!JSONSerialization.isValidJSONObject(self)) {
            print("无法解析出JSONString")
            return nil
        }
        let data = try? JSONSerialization.data(withJSONObject: self, options: []) as Data
        return data
    }
    
    func getJSONString() -> String {
        guard let data = getJSONData() else { return ""}
        guard let jsonString = String.init(data: data, encoding: .utf8)  else { return ""}
        return jsonString
    }
}

extension Int{
    var yuan: String { // 将 分 转换 为 元
        if self % 100 == 0 {
            return String(self / 100)
        }
        
        if self % 10 == 0 {
            return String(self / 100) + "." + String(self/10 % 10)
        }
        
        return String(self / 100) + "." + String(self/10 % 10)  + String(self % 10)
    }
}

extension UIViewController{
    // 以下判断 只在 viewWillAppear 中有效
    func isSwipeBack() -> Bool { // 滑动返回
        guard let itemCount = navigationController?.navigationBar.items?.count else { return false }
        guard let vcCount = navigationController?.viewControllers.count else { return false }
        return vcCount < itemCount && navigationController?.navigationBar.items?.last == navigationItem
    }
    func isPopBack() -> Bool { // pop返回
        guard let itemCount = navigationController?.navigationBar.items?.count else { return false }
        guard let vcCount = navigationController?.viewControllers.count else { return false }
        return  vcCount == itemCount  && navigationController?.navigationBar.items?.last == navigationItem
    }
    
    func isPushin() -> Bool { // push
        guard let itemCount = navigationController?.navigationBar.items?.count else { return false }
        guard let vcCount = navigationController?.viewControllers.count else { return false }
        return vcCount > itemCount && navigationController?.navigationBar.items?.last != navigationItem
    }
    /**************************/
}

extension UITableView {
    func scrollToBottom(_ animated: Bool) {
        let roews = self.numberOfRows(inSection: 0)
        if roews == 0{
            return
        }
        self.scrollToRow(at: IndexPath.init(row: roews-1, section: 0), at: .bottom, animated: animated)
    }
}